The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Zander on 22.01. 2017 09:47

Title: Oil leaks.
Post by: Zander on 22.01. 2017 09:47
My Gold Flash, which I got last Monday has been marking it's territory, with oil appearing on the floor in three places.
First one I looked at was oil from the flow and return pipe area. Nipping up the connections appear to have solved that one.
The second one is oil running from the top of the timing cover, at the front, which seems to be coming from the joint between
the dynamo and casing. I'm a bit puzzled by this, as I was under the impression that the dynamo chain was greased and not lubricated by an oil feed.  From other posts on here, it looks like I'll have to make sure its not coming from the inner casing joint.
The third leak is from the area of the rear of the primary drive cover, although it may be from the gear box, as there is oil in the centre stand spindle area.
The dynamo isn't charging, so having tested it in situ, it was necessary to remove it from the bike which suited me, as I could inspect the cork seal which is where I think / thought the oil was coming from.  The seal is in good condition, although it appears to be compressed to the extent that it's debatable whether it stands proud of the dynamo flange. A PO had put a smear of silicone sealant on it.  Any clues / guidance gratefully received!  Thank you.
Title: Re: Oil leaks.
Post by: bikerbob on 22.01. 2017 10:58
First the oil leak from dynamo area while you have the dynamo off you should  look at where the oil is coming from as well as possible failure of the inner case gasket there is also the possibility of oil coming in behind the large chain sprocket that sprocket is bolted to the idler pinion behind the inner case  there should be a cork seal behind that sprocket, now it is debateable wether this seal is required as the bush in the inner timing has a reverse scroll machined into it so any oil would be sent back into the inner case but if the scroll is blocked with gunge then the oil can run into the dynamo compartment. When I had my Gold Flash some years ago it never had a seal behind the sprocket and oil did not get into the dynamo casing my presnt A7 does have the seal however it also has a toothed belt drive and the seal came as part of the kit. The problem with leak behind the primary could be caused by a few things too much oil in the primary case, the felt washer could have failed this is fitted behind the sliding plate behind the clutch. Also it could gearbox oil in which case it could be the gearbox oil seal or the bushes in the constant mesh gear oil can also sometimes leak past these bushes if the bike is on the side stand.
Title: Re: Oil leaks.
Post by: Klaus on 22.01. 2017 11:20
Hi Zander,
welcome to this helpfull forum.
First lokation, please check the oilpipes also at the oilttank. Sometimes they get losen by vibrations and leck some little oil runing down the pipe on the backside. It also can happen that oil coming from the magnetofixing, and dripping down where the oilfeed is.

I think there a bad news with the oil coming out from the dyno. So I gues the idler pinionbush is heavy worn out, so oil is coming from the crankcase and filled up the the casing.

I assume the oildrops from at the end of the primaricover is from the enginebreather. You can find the end of the breather line left hand under the the cambush the little round casing next to the magnetocap. Blow by will spread some oil at the backside to the gearbox sprocket and than dripped down.
You can sort out if its gearbox oil or engineoil by smelling and color.

cheers Klaus
Title: Re: Oil leaks.
Post by: Zander on 22.01. 2017 20:07
Thanks for your comments bb and Klaus.  Sounds like the bike needs a bit more than a tickle here and there!  I had a look at the large dynamo sprocket and found it moves in and out by about 1 mm (endfloat), but there's not much movement clearance- wise.
The PO had also used silicone on the case gasket and I found a fair dollop of it in one of the chamber corners. Not good.  Re the dynamo, the comm seems ok,  but the field coil is not showing any resistance.  I've run it als a motor ok, but the "spin" test gave no readings, and the bulb failed to light on that test.  Overall condition of the dynamo internals and exterior is like new.  I also flashed it, to no effect. Unless I've missed something, looks like I'll be ordering a new coil, and if that works, I'll be chuffed.


Title: Re: Oil leaks.
Post by: trevinoz on 22.01. 2017 20:22
I wouldn't think that the dynamo would motor too well if the field coil is open circuit.
Title: Re: Oil leaks.
Post by: Zander on 23.01. 2017 07:18
I wouldn't think that the dynamo would motor too well if the field coil is open circuit.

I must  admit, the fact that it motored, albeit fairly slowly, was a surprise, but then, electrics to me represent the Dark Arts! 
Title: Re: Oil leaks.
Post by: bikerbob on 23.01. 2017 10:15
Before you go to expense of buying new parts go the subject on this website Lucas electrical ignition and look at my problems under the post Dynamo confused. I overhauled my Dynamo fitting new field coils armature bushes and bearings and connected the wires up as before the strip down but it would not charge even after flashing when the dynamo was running under test as a motor it was running clockwise it needs to run anti clockwisethis was solved by reversing the brush terminals now charges OK.
Title: Re: Oil leaks.
Post by: Zander on 23.01. 2017 10:31
I'll certainly do as you suggest, be. Thank you. *wink2*
Title: Re: Oil leaks.
Post by: Scott and Jay on 24.01. 2017 01:26
Hi Zander and welcome,

If it's the later A10 with the drive-side engine oil seal behind the cush drive - you might like to check this is still in place. Otherwise engine oil will fill up the primary. Forcing out of this oil seal, in turn, would be caused by excessive crankcase pressure - which I went through...
Title: Re: Oil leaks.
Post by: Zander on 24.01. 2017 10:13
Hi Zander and welcome,

If it's the later A10 with the drive-side engine oil seal behind the cush drive - you might like to check this is still in place. Otherwise engine oil will fill up the primary. Forcing out of this oil seal, in turn, would be caused by excessive crankcase pressure - which I went through...

I've yet to tackle the primary chaincase as I've been concentrating on the dynamo.
Today I'll have the inner timing case off to see what's going on there re the idler bushes.
I think the engine is 1960 but not sure, so will bear in mind your advice. Thank you👍
Title: Re: Oil leaks.
Post by: Zander on 24.01. 2017 14:17
Update:   It's a fact that when I got the bike, after running the engine for a few minutes, oil started running from the area of the dynamo seal down the front of the timing cover.  it's got to be coming from somewhere, so I've removed the inner timing cover and checked the idler bush and gear, neither of which seem to be badly worn.  The grooves on the idler bush are clear and there is, apart from 1mm end float, normal running clearance between shaft and bush. As far as I can make out, there shouldn't be any oil in the area of the dynamo drive chamber, so I suppose perhaps the idler bush should be a tighter fit than mine.  Sadly, it's not as clear cut as I would have liked, but I don't think I've any option than to buy a new one and try it.

Title: Re: Oil leaks.
Post by: TT John on 24.01. 2017 16:02
Zander.

Your quite correct in saying there should not be any oil in the dynamo compartment, so check your gasket that side also inspect the condition of the web inside the cover to make sure that it is sealing okay, the one that runs from the top down to just above the oil pump housing and make sure the web is complete. Sorry if I'm teaching you to suck eggs but there are some things which are so simple you can miss.

TTJohn
Title: Re: Oil leaks.
Post by: bikerbob on 24.01. 2017 16:14
Before you go to the bother and expense of a new bush which may not solve your problem, you say you have 1mm end float that is too much. Some 20 odd years ago when I did my first restoration on a Gold Flash I was concerned at the time that I could not buy the cork oil seal from any dealers at that time . I wrote to the tech consultant for the A10 at the BSA owners club who has now sadly passed away he was very helpful to me a number of times, he said that the seal was not really needed but if you did away with it you should put a shim between the idler gear and the inner case to take up the end float that would be present without the seal he did say how much the end float should be but I cannot remember but it was only a few thou. Why don't you try fitting a seal they are only made of cork the one on my A7 which came with the belt drive kit proved to be too thick so I reduced it's thickness down to around 1/16" thick it takes up the end play and also acts as a seal. The funny thing about these old bikes is what works on one bike is no guarantee that it will work on all.
Title: Re: Oil leaks.
Post by: Zander on 24.01. 2017 17:27
I tried a crude experiment to see if oil leaks from the end of the bush and the idler gear and it does, so a new bush may be needed.  I've also been thinking of ways to fit an oil seal, and I like the idea of the cork one, as I don't think it's possible to fit a lipped seal.
I'll also be having a close look at the faces and webs.  Have sourced most of the items needed from SRM, so may place an order tomorrow.
Thanks for your help BBC and TT John👍

Title: Re: Oil leaks.
Post by: Zander on 24.01. 2017 17:30
BBC?  Predictive text strikes again! Sorry, bikerbob🏍
Title: Re: Oil leaks.
Post by: chaterlea25 on 25.01. 2017 00:39
Hi Zander,
There is an oil scroll cut in the bush,
It has happened that inner and outer bushes have been fitted wrong way round leading to the scroll pumping oil into the dynamo case
If you are removing the inner timing case (before you do) check the rotating breather sleeve for looseness
Read the manual about fitting the cork washer to the breather sleeve,
If the sleeve is /was loose,  excess crankcase pressure will force oil out everywhere *sad2*

HTH
John

Title: Re: Oil leaks.
Post by: Zander on 25.01. 2017 08:27
Am sincerely grateful for all the constructive and helpful advice on here *thanks*
The investigation will continue today.
Title: Re: Oil leaks.
Post by: Zander on 25.01. 2017 18:10
Update2.  The scroll in the outer case bush is machined in such a way that  allows oil through instead of returning it to the crank case, so a new one is on the way.
I've also ordered the appropriate gaskets a set of tab washers and a full set of cork seals, so hopefully, I'll get it back on the road soon.
Title: Re: Oil leaks.
Post by: Zander on 27.01. 2017 15:41
Update 3.  Not a good day in the workshop today.  A plus point was the arrival of the parts I ordered yesterday.  Excellent service from SRM.   The new idler bush is tighter than the old, so that's good.  The machining of the scroll is pretty much same as the old one, so oil can pass through into the dynamo drive chamber - not so good.  The oil hole in the new bush is half the size of that in the original one, so it begs the question whether to leave it as is, thereby reducing the flow of oil into the bush ( and into the dynamo chamber,) or to drill it out after installing it in the housing. To reduce the end float on the idler gear to about 0.010" ( too tight)?, I intend making a bronze bush.  I'm also tempted to fit an oil seal in the boss, but it will mean loosing 3mm of support for the end of the idler shaft. I think it would be ok, as there doesn't seem to be much load exerted by the dynamo chain.
Offering up the new gaskets, the timing case outer is fine but the inner one seems way out.  Are there different casings for certain engines I wonder.  I'll be asking SRM that question. On the dynamo front, I've read bikerbob's posts, and also everybody else's, tested the armature/ commutator, field coils, connections and brushes, and flashed it. Dynamo motors in the correct direction as on the casing, but still no charge *sad2*
Title: Re: Oil leaks.
Post by: duTch on 27.01. 2017 22:15
 I suggest send the bush back  for the correct one.

I have no felt/cork/other seal in my idler setup, and it doesn't appear to leak any (and I run my belt dry), and I've had the cover off for various reasons a few times, so get the right bush and go from there.

 As TTJohn noted;
Quote
Your quite correct in saying there should not be any oil in the dynamo compartment, so check your gasket that side also inspect the condition of the web inside the cover to make sure that it is sealing okay, the one that runs from the top down to just above the oil pump housing and make sure the web is complete......................TTJohn
,

 The interface web on my outer cover was only in contact with the inner one by about half, and being only about 3-4mm wide was not much contact.
To rectify this, I widened the webs by having the main casing (or maybe the cover-or both) professionally built up with weld on the oil pump side and dressed it to suit- this was also necessary because the belt drive pulley was interfering with the web on its side, and needed fettling down with the Dremel.
 
Title: Re: Oil leaks.
Post by: Zander on 28.01. 2017 09:52
I think the bush is correct - it has the spiral grooves (scroll).  I'm also aware that this design must work, or there would be a proper "fix", so I accept that I'm probably looking to fix a problem that doesn't exist on the majority of A10's.  Regarding the idler gear end play, neither the crank case or inner cover bush heads show any sign of damage or excessive wear, but I'll fit a new gasket on the inner case and get an accurate measurement of end float, which I reckon will be over 1mm.  I'll also take into account the relationship of the idler and other gears in determining the size of spacer I'll make.
Needless to say, the gasket which was destroyed upon removal (inner case) is that which I have the problem with regarding the fit of the new one, so I'm reluctant to press ahead at the moment.  It will "sort of" fit, but it's not right.  Looks as though it's stretched about 4mm across the width.  I've emailed SRM to see if  my machine needs a different gasket.  It may, of course, be me just being a tart, but I want to get this job done properly, first time cos I want to ride it *smiley4*
The webs will come under scrutiny today - thanks for the pointers in that direction *wink2*
 

Title: Re: Oil leaks.
Post by: chaterlea25 on 29.01. 2017 21:54
Hi Zander,
The early and late A models had different cases and gaskets
The gaskets I have had from SRM for late models have been OK
The scroll should be in the direction so as when the shaft rotates it will bring the oil back into the inner side..
As to fitting a shim?
I would not fit a shim between moving parts, If a shim is needed remove the bush from the case and fit a shim between the case and bush shoulder

John
Title: Re: Oil leaks.
Post by: Zander on 30.01. 2017 08:37
Hi John
Thanks for info re the cases.  The one I got from SRM is too far out to use.  I emailed them but have yet to get a reply, so I've ordered another one from a different supplier hoping that I'll get a better fitting item.  Agree with your comment regarding the shim - I've placed it under the head of the bush.  While faffing about in the area of the timing chest, I noticed that the A/R bob weights were stuck wide open, so I've ordered new springs for that. The mechanism seems a bit stiff, so if the new springs don't sort it, it's off with the unit and something else to sort.  The dynamo continues to present a severe challenge.  I've not previously had a problem in this area and have always considered dynamo refurb to be a relatively simple job. Not this bugger, though *conf*
All good fun, ain't it?
Title: Re: Oil leaks.
Post by: KiwiGF on 30.01. 2017 09:14
It sounds like it might be time for you to invest in a set of "wadd" punches and some gasket material, once you've got the technique of making your own gaskets, you will hardly ever buy another gasket (or fibre washer)  *work* *bright idea*
Title: Re: Oil leaks.
Post by: bikerbob on 30.01. 2017 09:51
Agree I make all my own Gaskets except for the head gasket whenever I have any casing off I always make up 2 gaskets one as a spare. You can get gasket material quite cheaply on ebay. As regards the fitting of the shim this was advised at the time by the the then BSA tech consultant, I take the point about  moving surfaces if they were dry but that shim is well lubricated and when fitted to my then A10 it caused no problems in the 16 years that I had it and when I spoke to the present owner he has had no problems so that shim has been in place now for 20 years. You have factory fitted shims next to moving surfaces in the rocker box and the gearbox but as long as they are lubricated will not cause a problem.
Title: Re: Oil leaks.
Post by: Zander on 30.01. 2017 13:16
Yup, I made a few hole punches by turning  a chamfer on the end of a bolt and drilling the appropriate size hole in the end.  I had a stock of gasket material of various thicknesses but I've run out of a sheet big enough to make the one that I want.  SRM have replied saying that sometimes you have to trim them, but on the one I have, several of the holes are "hanging in the wind".  More gasket material on the way!
One of the reasons I put the shim under the head of the bush is that I don't have suitable sized materials in stock to make a washer type shim,  but was able to make one in two halves, which, as its encapsulated tightly between bush and inner cover, it won't be going anywhere.  I'd have been content to do it your way, bb. Thanks for the input, which is much appreciated.👍




Title: Re: Oil leaks.
Post by: chaterlea25 on 30.01. 2017 17:40
Hi Bob,
Rocker and gearbox shim washers are hardened so they work between moving parts
If you cut a shim from steel or brass shimming material they are not suitable for moving parts

John
Title: Re: Oil leaks.
Post by: Zander on 30.01. 2017 18:35
Stewart from SRM emailed me this afternoon offering to send another gasket, which I consider to be excellent service.  👍
Title: Re: Oil leaks.
Post by: ellis on 30.01. 2017 21:57
Nice Bloke Stuart. He is very helpful.
Title: Re: Oil leaks.
Post by: bikerbob on 31.01. 2017 09:26
Chaterlea I see now where you are coming from and I agree with what you say but the shim I used all those years ago was at least 1mm thick possibly thicker which will account for it lasting so long and if I ever have to fit a similar shim in the future I will harden and temper it just to be on the safe side cheers Bob.