The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: bikerboy on 09.03. 2015 01:54

Title: Engine done about 1800 miles since rebuild
Post by: bikerboy on 09.03. 2015 01:54
I mentioned this damned bike a year or so back and it is still giving me grief.

Its a 650 SR with 357 cam and it has twin carbs. When I built it I had everything done. Crank ground new big ends new mains new bush new guides new valves new rings the list is endless. It was resleeved and had new rings but the pistons (genuine hepolite) were reusable so I used them. Gapped the rings etc it has plenty of compression, to be honest its hard work to kick over.

It pours smoke out mainly on the left side but some from the right and you can smell the oil a mile away. It goes fine never misses pulls well etc just this damned smoke. Could it be something stupid before I pull the damned thing apart again?

I am using straight 40 oil.
Title: Re: Engine done about 1800 miles since rebuild
Post by: duTch on 09.03. 2015 02:09

 When I did mine, my mate said to wash the bores with soapy water and wipe it clean until no more black came off on a white rag, otherwise it'll smoke like buggery...so I did and it's not too bad- just a puff of smoke occasionally, but I think that's mixture issue...did you do that?
Title: Re: Engine done about 1800 miles since rebuild
Post by: kiwipom on 09.03. 2015 03:41
hi guys, it sounds like `rings 'or `valve guides` to me, if it has plenty of compression i would attack the guides first maybe some valve stem rubber caps, cheers 
Title: Re: Engine done about 1800 miles since rebuild
Post by: wilko on 09.03. 2015 05:48
 Valve guides? Fair crack o the whip! They hardly get any oil as it is. They aren't OHC engines with cams flooded with oil.Wet sumping, glazed bores, stuck rings, or broken rings.
Title: Re: Engine done about 1800 miles since rebuild
Post by: KiwiGF on 09.03. 2015 06:31
before stripping I suggest you check the oil seal is still in place on the drive side crankshaft, it can pop out if you get excess crankcase pressure, also better check that the timed crankcase breather is workjng as it should. A mates bike had similar symptoms due to a non functioning bunn breather, which went away after he reverted to the standard breather.
Title: Re: Engine done about 1800 miles since rebuild
Post by: bsa-bill on 09.03. 2015 08:50
Quote
Valve guides? Fair crack o the whip! They hardly get any oil as it is.

well not a lot but enough obviously.
what oil gets up there has to get out again, so drain holes  need to be clear, mine were certainly not, really needs barrels off though - sorry
Title: Re: Engine done about 1800 miles since rebuild
Post by: Triton Thrasher on 09.03. 2015 17:31
How long does a pint of oil last?
Title: Re: Engine done about 1800 miles since rebuild
Post by: muskrat on 09.03. 2015 19:07
G'day bikerboy. Do a compression test, hold throttle wide open and at least 10 kicks per side. I'd guess you broke a ring on assembly. Get a hold of a video endoscope and check the bore for scores. https://www.youtube.com/watch?v=LgbhePnUHiI
Cheers
Title: Re: Engine done about 1800 miles since rebuild
Post by: bikerboy on 10.03. 2015 23:44
Sorry to disappoint but 4 new valve guides when building new valves fitted new springs and the valves were cut by an engineering company not ground in. Parts from TMS in Nottingham so a renouned dealer not ebay specials.

Have had bores off to check rings and checked the ring gaps YET AGAIN :(

As I said there was no expense spared when I put this damned thing together about the only thing that was not stripped and totally rebuilt was the gearbox.

As for oil use lets just say I have to put a pint in every time I use it.

Compression test fine and repeated 3 times and I have already stuck an endescope down the bore no signs of any scores or marks. :(

I am totally baffled by it I have had the top end off once since the rebuild to check rings etc.

Mind you the good news is that it goes like shit off a shovel and not much overtakes me because they dont want to plough their way thru the smoke :)
Title: Re: Engine done about 1800 miles since rebuild
Post by: kiwipom on 11.03. 2015 07:20
hi guys, bikerboy oil can only get into the combustion chamber via the valve guides or up past the rings unless you have a cracked head, cheers
Title: Re: Engine done about 1800 miles since rebuild
Post by: beezermacc on 11.03. 2015 08:22
A couple of things, and these are only long shots so don't get your hopes up...... maybe the sump has too much oil in so, no matter how good everything is, oil is getting forced up past the bores. Normally you would also get oil passing the timing breather I know. In fact, is the timing breather aligned properly and is the escape airway clear? Is the pump scavenging properly? If you stop the bike how much oil is in the sump? (do you have a drain plug on your sump plate - makes life easier). Have you got the correct banjo bolts on the rocker feed pipes? A10 banjo bolts have very small holes whereas goldie ones have big holes so too much oil could be getting into the top end and pouring into the valve guides (unlikely but I said it was a long shot).
Title: Re: Engine done about 1800 miles since rebuild
Post by: trevinoz on 11.03. 2015 20:44
You say the pistons were OK but did you check that the ring clearances in the grooves were right? Apparently too much back clearance can cause the rings to flutter and act like pumps forcing oil past them.
You've done everything else so the pistons are looking like the last resort.
Title: Re: Engine done about 1800 miles since rebuild
Post by: KiwiGF on 12.03. 2015 01:08
As per my earlier post on whether crankcase pressure is the cause....this can be checked without too much work, if there is pressure in the primary drive case due to a failed crankshaft seal loosening the case filler cap should show gases escaping, some caps have small holes in them to release pressure which would also show gases escaping. If you have a leaky seal around the gearbox shaft as most bikes seem to then it may be that not much pressure will build up in the case though.

A failed crankshaft seal will prevent the timed breather from doing its job.

The timed breather should have a small puffing of gas coming out, from the hole in the crankcase provided for this, more so after the first few seconds after starting, on my mates bike it would start smoking out the pipes, mainly the left, at higher speeds, at tickover it was ok, he had a special bunn breather set up which did not work. It burnt oil at an incredibly high rate like yours, but did not run well and would barely exceed 60mph.
Title: Re: Engine done about 1800 miles since rebuild
Post by: bikerboy on 12.03. 2015 01:54
Thanks for all your replies and help this is my guesswork so far.

Possibly pistons as the rings fitted in them fine but they were pistons I had used before and never gave me a problem

Possibly the breather which I notice has been spoken about already. The guy who done the engineering work for me also botled the bottom end together and I am wondering if the crankcase breather is blocked. The oil seems to circulate fine but I have had it wet sump once and when I started it unusually it did not cover the garage floor which is suspicious. That to me would indicate a breathing problem, the bike not mine :)

The only other option is a cracked cylinder head (this head I did buy off ebay :() But as I had new valve seats made and fitted I would have expected any crack to become evident during that work or when I heated it up to fit the valve guides. I have not had the primary case off but it did have a new oil seal fitted on that side so I dont expect that to be the problem.

Looks like there is no easy fix then its take the damned thing apart again :(

The only other thing that occured to me was if the pressure relief valve was not working correctly that maybe crankcase pressure would build up then and force oil past the rings as it has nowhere else it really can go but I would have expected more signs of that and oil leaks galore which I dont have.

Thanks for all your suggestions as soon as I finish a Trident I have on the bench I will strip the damned thing down again :(
Title: Re: Engine done about 1800 miles since rebuild
Post by: KiwiGF on 12.03. 2015 04:22
the pressure relief valve will not cause excess crankcase pressure as it in the oil circuit and on most engines it only operates when the oil is cold and the pump can get to say 50 psi the rest of time it does not relieve any oil pressure as the oil pressure is always lower than say 50psi.

it is the timed breather that creates a partial vacuum in the crank case and if not working correctly can cause oil mist to get forced by the rings, I agree you would normally get gaskets leaking in this situation but if have a really good job on them and it sounds like you probably have ....they will hold up.....my mate had also fitted a new crankshaft seal but that did stop it being forced out of position after about the same miles as yours due to the excess crankcase pressure, in fact a new seal might be more prone to popping out of the case than one that been able to get well stuck in for a few years *conf*

As you can see I think it is worth eliminating as a possible cause before stripping the top end down again, unfortunately taking the primary apart can take a while as well  *conf*
Title: Re: Engine done about 1800 miles since rebuild
Post by: duTch on 12.03. 2015 08:05

 Why not pull both timing covers so you can blow air through the gallery to the exit hole....? You should be able to do it with a small lungful, and if any resistance poke some wire through, and also up the exit hole and blow again until it clears- maybe a mudwasp or similar has made a refuge in there while you weren't looking.

 This'll enable you to check the rest of the breather dynamics also.
 
 When you say
 
Quote
but I have had it wet sump once and when I started it unusually it did not cover the garage floor which is suspicious.
, how much oil was missing from the tank...? I'd say unless it's missing more than a significant amount, it's reasonably 'normal', and not a real 'wet-sump' situation
Title: Re: Engine done about 1800 miles since rebuild
Post by: trevinoz on 12.03. 2015 20:53
Kiwi,
           Are you forgetting that prior to 1953 there was no crankshaft seal and that the breather system obviously worked OK?
Title: Re: Engine done about 1800 miles since rebuild
Post by: KiwiGF on 12.03. 2015 21:21
Hi Trev, I don't know how the breather system works on a 53, but the question was asked about a super rocket which should have the later design, and a rubber seal?

Out of interest though..... is the drive side crankshaft seal on a 53 non existent (which would beg the question how a partial vacuum could be achieved) or does it have a close fitting metal bush on the crank, like my b31 has?
Title: Re: Engine done about 1800 miles since rebuild
Post by: wardleybob on 12.03. 2015 21:27
Hy just a idea I once had similar symptoms and it turned out to be the return pipe slack in the crankcase. It was returning oil whitch seemed fine but not enough. I clued it in and it was fine.
But you have to strip the engine down.
Title: Re: Engine done about 1800 miles since rebuild
Post by: duTch on 13.03. 2015 00:05

 Kiwi,I'd also considered that but let it ride- from memory, mine had a kind of oil slinger outboard of the bearing, so the pressure would be constant-ish, or just 'oscillate' between the two as need be..I guess,
 My engine originally had no seal (stamped 23.12.52), but I had it (cases and the cush-bush) machined to accommodate one
Title: Re: Engine done about 1800 miles since rebuild
Post by: bikerboy on 13.03. 2015 00:30
Again thanks for all the replies and my first option is to do exactly as Dutch suggested which taking the timing covers off and checking that the breather gallery is clear, by rights I should be able to poke a welding rod down there.

The oil pickup pipe from the sump is also a good idea altho I did have this out during the rebuild and I am fairly certain it is well in there.

The more i think about it the more I think its got to be crankcase pressure because I do have a slight oil leak from the sump despite trying to reseal it two or 3 times and to be honest they dont normally leak particularly as i faced it all up (like I did most of the surfaces) during the rebuild.

Dutch, when it wet sumped after about 8 weeks without being started it virtually emptied the oil tank. This has not been a problem since because I start it at least every 3 days now but at least a strip down would allow me to cure that problem while i was at it. Yes I know I should have worked harder at that when I built it :(
Title: Re: Engine done about 1800 miles since rebuild
Post by: trevinoz on 15.03. 2015 02:23
Biker,
           When you get the barrel off, have a good look at whether the rings are bedded or not.
Probably a nice coarse hone will solve your problem.
Title: Re: Engine done about 1800 miles since rebuild
Post by: Dean on 15.03. 2015 21:44
When I first got my bitsa A10 on the road its leaked oil everywhere. No I don't mind the odd leak but this was getting real messy so I decided to have a look into it. I can't remember what made me decide to look at the timed breather but when I got it off I thought I'd poke around the breather hole behind it in the crankcase and succeeded in extracting a chrysalis *eek*. Sorted

Moral: even thoroughly cleaned cases can get messed up if you leave them lying around for long enough  *smiley4*
Title: Re: Engine done about 1800 miles since rebuild
Post by: bikerboy on 25.05. 2015 00:12
Well I got around to stripping the damned thing and still cant find anything wrong with it.

Rings fine, pistons fine, rechecked gaps on rings maybe a tad big but nothing to mention.

Breather 100% clear.

Have not split the cases yet because I cant get the damned crank pinion off but I cannot see anything that might cause it even tho there is obviously clear sign on oil burn mainly on the left hand cylinder.

Any decent tips for getting the pinnion off or should I make something?
Title: Re: Engine done about 1800 miles since rebuild
Post by: RichardL on 25.05. 2015 02:06
Sorry about referring you to one of my own posts, but this is what I used, with the tips of the puller ground for a close fit in the pinion.

http://www.a7a10.net/forum/index.php?topic=8738.msg62472#msg62472

Richard L.
Title: Re: Engine done about 1800 miles since rebuild
Post by: Triton Thrasher on 25.05. 2015 09:12
You had it sleeved, but are using the previous pistons?  That's unusual, because sleeving is done when a barrel is worn out, after having already been rebored to take oversized pistons.  Sleeving takes the bore back to standard, so your oversized pistons can't be used. 

Otherwise:

Upside down ring?

Too-smooth hone? Should be 150 grit or even rougher. I think mine (Triumph) was 130.

Running in with oil that is too "good?" Rings bed in better with running-in oil or cheap low spec oil.

Failing to make the engine pull hard in midrange rpm when running in, especially on its first run.

Using silly thin modern oil, like 10W/40.

With a magnifying glass, it's supposed to be possible to see if the rings' edges have been wearing against the bore. If there are areas of no contact, the rings can't work. I've never tried looking, because I haven't had the problem.

If oil is going down the guides, there should be visual evidence.
Title: Re: Engine done about 1800 miles since rebuild
Post by: edboy on 25.05. 2015 11:17
hi bikerboy. have you given the valve guides a sharp tap with an ally drift? if any move when cold they bypass oil when hot.another possibility is a crack somewhere in the head or barrel area.just suggestions from similar experiences.
Title: Re: Engine done about 1800 miles since rebuild
Post by: bikerboy on 26.05. 2015 23:41
You had it sleeved, but are using the previous pistons?  That's unusual, because sleeving is done when a barrel is worn out, after having already been rebored to take oversized pistons.  Sleeving takes the bore back to standard, so your oversized pistons can't be used
----------------------------------------------------------------------------------------------------------------

The sleeve at the bottom of the barrel was cracked thats why I had them sleeved they were not worn out and it was cheaper to have them bored out to +20 and keep the pistons (which appear fine) than what it was to buy new pistons

The rings are new but original hepolite and there is no indication of a top or bottom they only have a tiny chamfer both sides

The sleeve bore hone was done by a real BSA engineering expert so I doubt its that.

Oil straight 40 Morris cheap and cheerful

Unfortunately I dont take it that easy running in or not lol

Guides new 2 of the 4 oversize and reamed out and valve seats replaced in engineering shop.

The only thing left to suspect is that its not scavenging well enough so it looks like another £300 on an SRM oil pump :(

I have gone over head and barrels with a fine toothcomb looking for any sign whatsoever of crack and cant see any sign plus the fact I doubt that would cause it to smoke on both cylinders even if the left hand one is a bit worse than the right
Title: Re: Engine done about 1800 miles since rebuild
Post by: jachenbach on 27.05. 2015 02:56
You may want to run a leakdown test before taking the top end apart. If it can pass leakdown, I'd look at the other items mentioned above and not disturb the top end.
Title: Re: Engine done about 1800 miles since rebuild
Post by: Triton Thrasher on 27.05. 2015 06:45
How much oil is in the crankcase, when you stop the engine?
Title: Re: Engine done about 1800 miles since rebuild
Post by: bikerboy on 08.06. 2015 00:35
Forgive my ignorance but what do you call a leakdown test?

I have not measured what is left in the sump to be honest. One I cant stop it leaking, which leads me to believe there is to much in there.

I seriously believe the only thing that can be causing it is to much oil in the sump forcing its way past the rings. I cannot for the life of me think of another possibility.

I aim to check the scavenge pipe, make sure (yet again) that all the oilways and breather pipes are clear, change the check valve and probably replace the oil pump (draganfly has recon ones with a different body for about £90, exchange of course) If all that does not stop it smoking I think I will set alight to the damned thing lol
Title: Re: Engine done about 1800 miles since rebuild
Post by: duTch on 08.06. 2015 01:50


 I'd call a leakdown test a "leakdown test"  *smile*....but my understanding of what it is, is pumping a certain amount of compressed air into the cylinder under control, and with a pressure gauge in place, measure how much the pressure changes in a given time....or something like that?
 Someone posted a fairly detailed 'how to' on here a while ago...do a search.... *conf*

 But before you go berserk, go for a spin, and then drop the oil from the sump...I measured about 160ml, recently with a standard old oil pump, without doing everything suggested you're pushing the proverbial.....*whistle*... *dunno*
   If there's a healthy return, I can't see how it's a problem, I'm interested how much other people measure too...??

 The check valve as I see it does nothing other than attempt to stop oil bleeding down from the oil tank when dormant(not running), when running, it does nothing.

  I suggested this on the first page, did you try it...works for me, but I 'didn't not' try it...

 
Quote
When I did mine, my mate said to wash the bores with soapy water and wipe it clean until no more black came off on a white rag, otherwise it'll smoke like buggery...so I did and it's not too bad- just a puff of smoke occasionally, but I think that's mixture issue...did you do that?
Modify message

Title: Re: Engine done about 1800 miles since rebuild
Post by: jachenbach on 08.06. 2015 13:30
Leakdown testing is, as said above, done by pressurizing the cylinder with engine locked at tdc. A compressor is connected to a pressure regulator, air then goes through a gauge and on to the cylinder by way of the spark plug hole. A valve after the gauge is closed with compressor on and the gauge (which reads percent leakdown) is zero'd. The valve is then opened and percent leakdown is read. A nice tight engine will imo be under 5%. If there is a serious problem (like 20%) you can hear the air. The nice thing about leakdown is by seeing/hearing where the air is escaping you can often pinpoint the source of the problem. For instance, air coming from the oil filler will be getting by the rings. From the carburetor is getting by the intake valve, from the exhaust pipe it's getting by the exhaust valve, etc.
Leakdown testers can be bought for under $100 US.
Title: Re: Engine done about 1800 miles since rebuild
Post by: bikerboy on 28.06. 2015 00:47
Thanks for explaining a leakdown test to me I have to admit I have never heard of it before but it does sound damned useful.

Dutch the reason I am doing the check valve again is it still has a tendency to wet sump despite the recent rebuild.

Anyway I still cant find anything wrong with it I have even gone as far as taking the sludge trap end caps off in case the guy who reground the crank and fitted it done something wrong in there. Yes I know there is nothing to go wrong in there really but I am really grasping at straws now :(
Title: Re: Engine done about 1800 miles since rebuild
Post by: jjbsa on 28.07. 2015 18:20
Hi,
Many years ago I had a home built RGS lookalike, which after a rebuild oiled up on the LH pot really really badly.  After looking at other possibilities, it turned out that the return side of the oil pump was sucking in air past the pump gasket, which isn't very wide at that point.  This was caused by me attempting to enlarge the hole in the crankcase from the sump oil pickup. I reshaped the hole and the problem went away.
HTH,
Jon
Title: Re: Engine done about 1800 miles since rebuild
Post by: bikerboy on 21.09. 2015 20:41
Jon

Thanks for that tip, I have stripped the engine and rechecked everything which still appears ok. I have yet to test it yet but if it still smokes and burns oil like there is no tomorrow my next move is a reconditioned oil pump, I see Draganfly are doing one which is a lot cheaper than the SRM one
Title: Re: Engine done about 1800 miles since rebuild
Post by: bikerboy on 03.06. 2016 01:45
Well I am a right happy bunny :)

After two years I have eventually found the problem

The only thing left for me was the pistons. I replaced them and hey presto. Smoke gone :) Plugs a lovely biscuit brown colour with a black ring around the outside.

The baffling thing is the compression is still the same? Odd but I dont care at least I can ride now without leaving a trail of gassed bodies behind me :)
Title: Re: Engine done about 1800 miles since rebuild
Post by: muskrat on 03.06. 2016 07:21
Good news. So what breed of pistons were they and what breed now? Could it have been the infamous JP rings? Or a slow run in?
Cheers
Title: Re: Engine done about 1800 miles since rebuild
Post by: bsa-bill on 03.06. 2016 08:24
traditionally Italian pistons needed a bit more clearance, maybe it had been re bored for them then other smaller pistons put in
Title: Re: Engine done about 1800 miles since rebuild
Post by: KiwiGF on 03.06. 2016 12:06
Well done biker boy, persistence is needed often with these bikes!

Edit: and many thanks for "completing" your thread and telling us all about how you solved it he problem.
Title: Re: Engine done about 1800 miles since rebuild
Post by: jjbsa on 04.06. 2016 00:07
If a change of pistons cured the oiling, and the oiling was on just one piston (the LH one) then I might suspect the up and down clearance in one or more of the piston rings in their grooves.  Excessive clearance there can allow the piston rings to move up and down and act like a very short stroke pump, letting oil past the rings round the back. Clearances generally should be 0.7 to 2 thou max.
Back in the 60s I once had a Hepolite piston where the oil holes drilled in the back of the oil ring groves were all over the place and drilled at an angle so that when the piston was descending they filled with oil and then released it back into the ring groove on the upstroke.  This caused oiling which was cured by using a needle file to open the hole out to remove its downward angling.  The original holes looked like they were drilled with a hand drill!  What a total difference from today's best pistons such as Wiseco and JE.

Re leakdown tests.  I have found these VERY useful in pinpointing where leaks are and they really do show that its possible to grind in valves and still have poor sealing if the seats weren't cut pretty damn accurately beforehand.  In fact the tests show that if the seats are cut accurately then subsequent grinding often doesn't improve anything.  I'm a convert to leakdown tests.  I clamp the cyl head with valves in to a metal plate with a thick rubber ring to seal it and put the compressor pressure through a blow gun to an old spark plug in the plug hole.  You don't have to have valve springs fitted, if I do then I generally use little weak checking springs.  If the valves seal well then there is no hissing and the head, once pressurised, will hold pressure for 20 or 30 secs before a valve (without a spring) drops down.  If it leaks you hear a hiss when the pressure is applied and a little strip of paper moved around in the port will flutter and quickly show just where it comes from.  It's embarrassed me a few times!
Title: Re: Engine done about 1800 miles since rebuild
Post by: mugwump on 04.06. 2016 09:28
Bikerboy, I'd be interested to know what the old pistons were and what you replaced them with.
Title: Re: Engine done about 1800 miles since rebuild
Post by: cableguide on 05.06. 2016 20:11
Hi there,
Glad to hear new pistons have sorted the problem, though it does make me think this....Imagine the bores were done a bit over and the old pistons where a bit under, might explain the problem to some extent..how do the bores measure up?. and how do the new pistons measure up against the old ones. Anyway great result.
Title: Re: Engine done about 1800 miles since rebuild
Post by: bikerboy on 09.06. 2016 23:17
Firstly I may be celebrating to early :(

Tonight after riding about 25 miles at about 65 mph I lost most of my oil out of the engine breather. But at least it never smoked lol.

These are the pistons I used and they are from TMS Nottingham

http://www.tms-motorcycles.co.uk/store/products/popup/?imgversionid=3&itemid=1685

Just to answer a few other questions in the last couple of posts.

I had the bores resleeved and bored to +20 imperial purely because I had a set of pistons that size.

The new pistons were metric which meant the bores needed to be 70.5 (I think).

What I did was take the barrels, the old pistons and the new pistons to the guy who done the rebore. He measured it in front of me and everything was great. He tried the rings, gapped perfectly as I already knew and told me there did not seem to be any reason for it to smoke.

He honed the bores for the new pistons while I stood there as the difference apparently is miniscule.

I put it together, smoking stopped, oil stopped pumping out of the breather and my world was complete for about 2 days. I deliberately put a pipe on the breather and threaded it thru to the top of the gearbox my side so that I could monitor it easily temporarily of course.

Drove to work this morning about 15 miles, no smoke, no oil loss and averaged about 65 mph as its all motorway.

Drove home via a friends house so it was about 40 miles (same average speed about 65 ish) and got home to an extremely oil covered right leg and an empty oil tank :(

I so hate motorbikes at this moment in time :(
Title: Re: Engine done about 1800 miles since rebuild
Post by: mugwump on 09.06. 2016 23:50
I don't think the problem is piston/bore related. Without reading back over the whole thread, has it been suggested that either-the feed /return oil pipes could be reversed or a leak on the feed side either the pump body or the anti sumping ball valve.
Title: Re: Engine done about 1800 miles since rebuild
Post by: bikerboy on 10.06. 2016 03:14
The oil pipes are not reversed they are labelled and it has been circulating perfectly.

At the moment I have an external anti sumping valve fitted for test purposes in case it was the check valve
Title: Re: Engine done about 1800 miles since rebuild
Post by: Ted_Flash on 10.06. 2016 06:47
Similar happened to me with an A65, the previous owner had used lots of silicone in the engine and bits had collected on the sump filter, so oil was slow in getting through to the pump pickup.  Is your gauze clear?
Title: Re: Engine done about 1800 miles since rebuild
Post by: Triton Thrasher on 10.06. 2016 08:57
As above, piston and bore condition does not fill the crankcase with oil.

Wet sumping (after starting a ride with an empty sump) is a failure to pump oil out of the sump.
Title: Re: Engine done about 1800 miles since rebuild
Post by: jjbsa on 10.06. 2016 09:20
Bikerboy, I know it looks like you've cured the oil-use problem and that you've now got an oil slinging problem (all part of the fun of Brit bike custodianship  *smiley4*), but as it looks like the TMS pistons were involved in the first problem, have you had a close look at them to try and find a cause.  I'd be interested to know what the up and down play on the rings is, and what the oil holes behind the oil rings look like - how do they compare with other pistons that you have?
Title: Re: Engine done about 1800 miles since rebuild
Post by: Topdad on 10.06. 2016 10:19
His there a visible return at the oil tank after its warmed up and is the any pressure in the oil talk when you take off the oil filler cap ,just wondering if the oil tank breather is blocked ?
Then the pump, I think you've checked the pump ,do you have a spare? why not  try it ,if not could you borrow one ,I seem to remember you said the pump was new but even new can be broken . sorry grasping at straws but I agree with TT , keep trying Bob
Title: Re: Engine done about 1800 miles since rebuild
Post by: mugwump on 10.06. 2016 10:42
Friend of mine acquired a Huntmaster that had allegedly been re-built, soon blew up throwing conrods etc. On inspection found no trace of the anti sumping ball valve/spring or retaining screw inside the crank case, ( Bikerboy, I'm was not refering to anti sumping tap fitted externally). If, I know its a long shot, the valve has been left out or come undone this will fill the sump and starve the essentials of oil. 
Title: Re: Engine done about 1800 miles since rebuild
Post by: edboy on 10.06. 2016 18:27
bikerboys problem sounds  like a crankcase strip to me. i would look for a loose pick up pipe, or cracked as air is being returned to the oil tank and the oil is being pumped out the breather. it couild be a blocked oil line or oil pump fault but you have checked this with an air line? yes? a loose pick up is a common problem on triumphs.
Title: Re: Engine done about 1800 miles since rebuild
Post by: muskrat on 10.06. 2016 21:01
Do you have an inline spin on oil filter fitted? Fitting the pipes the wrong way might cause problems.
It does sound like scavenge problems. Pull the pump off, drop the sump plate, fit hose to scavenge pipe connected to compressed air, finger over the hole and listen for leaks.
Cheers
Title: Re: Engine done about 1800 miles since rebuild
Post by: chaterlea25 on 10.06. 2016 21:55
Hi,
By any chance do you have a sump plate with a magnetic  drain plug fitted?
It happened to a bike I rebuilt that the magnet was preventing the ball in the pickup pipe from being sucked open *ex* *ex*
Fit the sump plate with the magnet furthest away from the pickup pipe, or remove the magnet and fit a weaker one
If the sump filter is incorrectly fitted and the hole not lined up to the pickup pipe similar problems can occur

John
Title: Re: Engine done about 1800 miles since rebuild
Post by: KiwiGF on 10.06. 2016 22:35
Another clutch at straws but is the oil supply to the head set up correctly? I think the system relies on holes in the bolts having the correct diameter etc, although I suspect the narrow bore copper pipe feeding the head also provides a significant restriction that prevents too much oil going to the head. I'm not sure exactly what would happen if the drain hole in the head gasket was blocked and preventing oil dropping from the rocker back to the sump but I'm pretty sure the engine would burn lots more oil......

I'm not sure how one could test not too much oil is going to the rockers but on mine I would describe the feed as a little more than a fast drip.

On the other theory of oil building up in the crankcase before blowing out of the breather, I've not experienced (wet sumping) myself this but the oil level would have to get pretty high in the cases to get flung around do that some reaches the breather? And if so there would be a significant drop in the oil in the tank and a noticeable drop in the amount of oil returning to the tank when the oil build up is occurring? Both those things should be pretty evident, and the return system is pretty simple, and once oil has reached the return side of the pump it would take pretty complete blockage to prevent the oil getting back to the tank as the pump can pressurise the return system the same as the supply side if necessary (it shouldn't be necessary mind).

On the anti wet sumping screw being missing, I cannot remember for sure, but isn't that in the supply side not return? (apologies if I have that wrong.......).

I've always thought that if the scavenge pipe was not present or cracked the oil level would not rise that much before oil reached the the hole in the crankcase where it is fitted anyway, so a good safe design by BSA, but obviously I've never tested that theory!
Title: Re: Engine done about 1800 miles since rebuild
Post by: Beeza on 10.06. 2016 23:56
Hi, I have seen this situation where oil at some point just pumps out the breather and was caused by a sticking ball in the sump pick up. The only thing this fellow had done was to use a different oil, when he popped the sump off and tapped the ball we discovered it was stuck down. He went back to the caravan park changed the oil back to his original type and rode the rest of the weekend. I don't know what either oil was.
Hope this helps a bit in this saga.
Also take care with oil pump gasket hole alignment, I just fitted an SRM pump (yep I'm rich), left the timing cover off and the next day oil pool. The gasket oil hole had aligned slightly with the stud hole and leaked out past the stud, when I pulled the gasket out I could see the impression in the SRM supplied gasket where both holes had crossed over, I then made my own gasket.
Good luck
Thomas
Title: Re: Engine done about 1800 miles since rebuild
Post by: muskrat on 11.06. 2016 10:45
While the engine is going there shouldn't be much more than a cup full (250ml) of oil in the motor. After a minute or so from start up you should see bubbles coming out of the return stand pipe in the oil tank.
The incorrect banjos with the larger hole will make a difference but the scavenge pump should still be able to clear it, just not as quickly.
Cheers
Title: Re: Engine done about 1800 miles since rebuild
Post by: shuswapkev on 12.06. 2016 13:02
installing the compression rings upside down will do exactly as you have described....
  I have bought 4 bikes over the years...owners have given up on...Suzuki Hondas and BSA ...
comp rings were upside down...engines ran great but smoked like buggery
 
  on some rings there is a chamfer on the inside....that has to be installed as manufacturers instruction..

    hope this is your problem  its a cheap fix
Title: Re: Engine done about 1800 miles since rebuild
Post by: bikerboy on 15.06. 2016 03:07
Right let me try to answer as many questions as I can and btw thanks for all your advice.

Since it was rebuilt I have had it totally apart twice trying to cure this problem. Both times I have replaced the check valve behind the oil pump just in case. The TMS pistons cured the smoking problem not caused it the old pistons caused it.

I do not have an external oil filter fitted.

The oil has never failed to circulate that I know of and I check it every time before I ride it (yes I am paranoid about this bike lol)

I do not have a magntic sump fitted I took the cheap option and welded a nut inside the sump cover to give me a drain valve and no it is not hitting the gauze.

The gauze is perfectly clean. The pickup in the sump checks out completely no leaks or cracks.

Now for the latest developments. After throwing all its oil out and virtually draining the tank I took the seat off (yes it was full of oil under there as well) covered the bike in foam gunk and attacked it with the pressure washer. At least that got rid of the oil :)

I topped up the tank with my normal Morris straight 40w and waited for it to do it all again. 200 miles later (140 0f them in the same day) it has shown no sign whatsoever of pumping any oil out???????? The only difference being that I never went above 55 mph.

Now IMO the only thing that causes oil out of the breather like that is excess oil in the sump. Faulty scavenge has to be the problem IMO. If its speed related (when it happened I had been cruising at 65/70) then again IMO all it can be is the oil pump. Thats my theory anyway so if it happens again I will change the oil pump and see where that takes me.

On the plus side barring a slightly dragging clutch (yes the whole thing is new including the bearings, 4 spring type) the bike is a pure pleasure to ride and it does not smoke :):):)

Today, after my 140 miles I fully realised exactly why I fell in love with A10's 45 years ago whether I will feel the same the next time it covers me in oil I dont know ;)
Title: Re: Engine done about 1800 miles since rebuild
Post by: bikerboy on 15.06. 2016 03:19
beeza

Agree with you on the oil pump gasket as they are very loose fitting but I was extra careful with it.

I have wondered if its all the same problem but repalcing the pistons has diverted it so to speak.

What if the sump has been pressurising all the time and with the old pistons and rings oil could force its way into the combustion chamber? Now with the new pistons it cant get by so easily so is blowing out of the breather instead?

Just a thought I had which I am not taking that seriously but I assume it might be possible.

The oil lines is a good shout as well if the return is collapsing under pressure the oil would have nowhere else to go but out of the engine breather. I might change them as a matter of course anyway just in case.

For those that mentioned it I have never checked the oil for circualtion hot or cold and seen a problem it appears to pump away quite happily but I never checked it the night it all blew out. It was dark and as I had rerouted the breather pipe on to my side of the bike (near my foot) to keep a close eye on it. Needless to my leg was covered in oil and I just wheeled it into the garage.

On a plus side my dodgy ankle moves a lot easier now and my knee has stopped creaking ;)
Title: Re: Engine done about 1800 miles since rebuild
Post by: Topdad on 15.06. 2016 10:47
I can see it now , Daily Mail headline .... wonder cure for arthritis ...use straight 40 motor oil as recommended by the BSAA7 and A10 forum  members *dunno2* *doh*
Title: Re: Engine done about 1800 miles since rebuild
Post by: chaterlea25 on 15.06. 2016 20:34
Hi Bikerboy,
If the rotating breather cork washer is not "compressed" enough it may be possible that crankcase pressure is building at higher speeds ???
I have found that the corks can compress and loosen over time,
If you remove the outer timing cover see if you can rotate the breather sleeve (a little within the confines of the fit of the driving peg) with your fingers
If you can its too loose  *ex*

John

Title: Re: Engine done about 1800 miles since rebuild
Post by: trevinoz on 15.06. 2016 22:20
I would be inclined towards the ball in the pick-up having stuck closed.
Another possibility is the oil draining from the scavenge pipe and the pump losing its priming.
Title: Re: Engine done about 1800 miles since rebuild
Post by: bikerboy on 16.06. 2016 00:17
Charterlee

Its not the cork for sure if anything I would suspect that of being marginally tight.

I have got an external anti sump valve on it temporarily just for test purposes and whenever I check it I take the lid off kick it over and as soon as it starts the oil is returning. I have also checked it virtually every time I have got home (barring that night as I said) and there has been a healthy return every time.

There is a guy in havant thats rebuilding oil pumps at a reasonable price includign using an alloy body so I am going to get one of them anyway as a matter of course and I am definitely changing the oil pipes. Once thats done I will try to hold it at a higher soeed for 25 or 30 miles to see if I have a repeat of the problem.

Its a bit bizarre cos in my foolish youth when we had no money and parts were cheap I bodged many an A10 engine, one I remember I left a compression ring out cos I could not get one and was going away, yet I never got anywhere near the trouble I have had with this one and I have lavished £1000's on it lol

Somewhere there is a lesson to be learned there no doubt ;)
Title: Re: Engine done about 1800 miles since rebuild
Post by: bikerboy on 01.07. 2016 01:27
Well for those interested so far this bike has behaved immaculately. Starts fine, runs great, smoking problems gone and still no oil blown out again.

Baffles me
Title: Re: Engine done about 1800 miles since rebuild
Post by: Klaus on 01.07. 2016 06:50
Well for those interested so far this bike has behaved immaculately. Starts fine, runs great, smoking problems gone and still no oil blown out again.

Baffles me

Sometimes bike will be baffling, the same way as woman. ;)

Everything with wheels and tits can cause problems *conf*

cheers Klaus
Title: Re: Engine done about 1800 miles since rebuild
Post by: muskrat on 01.07. 2016 21:01
Fingers crossed for you bikerboy.
Klaus, good to see that expression is universal. Down here it's " if it's got wheels or tits it'll give you trouble and cost you money).
Cheers
Title: Re: Engine done about 1800 miles since rebuild
Post by: bikerboy on 25.09. 2017 02:20
Just to totally end this thread I can safely say now that all problems are cured.

Its been well over a year since the last comment on here and the bike has done 8000 miles since without any problems as such.

Yes a few nuts and bolts have vibrated off but it runs like a dream.

Thanks everybody for your suggestions on the problems and without a doubt the problem was the pistons. The oil problems after were of my own making. It had wet sumped and I never realised it. I topped the oil up and of course when the oil was dragged out of the sump it was over filled and all flew out of the turret in the oil tank.

The bike is a total joy and goes like the clappers  *smile*

Just one thing, anybody that suggested I was running in too slow really does not know me at all  *smile*

Had you have said "ease up you idiot you are running in" you might have got it right  ;)
Title: Re: Engine done about 1800 miles since rebuild
Post by: cableguide on 01.01. 2018 18:28
Hi Bikerboy,

Just wondering what ur final thghts are re the oil. Does it now look like it was the oil pump after all..or is it still to difficult a problem to put ur finger on.
My A7SS still puffs a bit after new guides, valves, a resleeve and NOS Hepolites...so frustrating.