Author Topic: Well what a disastrous rebuild this has been  (Read 12630 times)

Offline bikerboy

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Well what a disastrous rebuild this has been
« on: 17.04. 2013 02:26 »
Rolled the Super Rocket out today after a total rebuild from head to toe. What a disaster.

Firstly when I put fuel in the tank one of the brand new taps leaked like a sieve when I turned it on.

Next on kicking it I found that it had wet sumped and I only put the oil in 2 weeks ago. I also cleaned out the spring and ball bearing etc when I had the crankcases apart.

After emptying the sump and blanking off the faulty fuel tap I was ready to start. Not a peep, nothing whatsoever. I had a spark, I had fuel but I could get no reaction from it whatsoever not even a kickback or a backfire.

Swapped the leads around even tho I knew the timing was not 180 degrees out, swapped them back again. Checked the plugs not particularly wet and they were sparking. After an hour I gave up but I am pretty down about it. The engine has had just about anything that can be done done to it. Regrind, new shells, new bush, new bearings, new camshaft, relined bores and for once I am totally stumped. The only thing I will say is it feels odd to kick over but it felt odd before I put fuel in it. Its hard to describe but its just odd. When I kick it over with no plugs in it feels fine but as soon as i put plugs in its like it has about 12:1 compressions ratio its so hard to kick. The whole bottom end was put together by a place called the rebore shop, which is highly rated by classic bikers. It all turns wonderfully but it almost sounds like the exhausts are blocked or something. They are not they are brand new and it sounded like this when I kicked it over with no damned exhausts on. Any brainwaves from anybody ?

I will say I did rebuild the mag with new bearings and brand new points but the spark is nothing special. Yes it sparks but its not some wonderful zap or anything. Even if the mag is not perfect I would expect some sort of response. Its also twin carbed so the chances of both carbs being faulty are pretty damned low.


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Re: Well what a disastrous rebuild this has been
« Reply #1 on: 17.04. 2013 08:21 »
Bugga, don't you hate that. I know that sinking feeling.
You know for the cost of a cup of hot chips a new ball and spring should have gone in *problem*.
Is the cam timing right?
My cafe feels like that to kick after a new set of rings, but it is 9.5:1. Once warm it's a lot easier. Yet to work out why.
If the mag only gives a so so spark with the plug out it might not have enough berries when the plug is in and under compression. It is a lot harder for the spark to jump. Can you borrow a good mag of a friend to try?
Cheers
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Online KiwiGF

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Re: Well what a disastrous rebuild this has been
« Reply #2 on: 17.04. 2013 08:37 »
cThis is one of those count to ten moments  *smile*

Its not uncommon the rotters wont go, theres a lot of things that need to be right...

Youve checked the " obvious" but its the less obvious with sods and murphys laws thrown in for good measure that tends to apply to new builds ....

Yr plugs should probably be quiet wet if youve been kicking it over for a while, and this would stop it sparking, so I reckon its worth checking the carbs e.g cleaning jets and checking all filters are not blocked, maybe try different fuel. The fuel as i once had a bitter experiençe where i had accidentally mixed some diesel in with my petrol....

On my rebuilt bike I .....eventually....found out the carbs idle circuit was blocked, then once that was sorted the tickler which doubles as an air vent was found to be blocked, so mine started wll but died shortly after unless the tickler was held down. It took me ages to get it running ok.

Ref the funny feeling when kicking it over, is it stiff to kick over with plugs out?
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Online Billybream

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Re: Well what a disastrous rebuild this has been
« Reply #3 on: 17.04. 2013 09:00 »
Happen,s to my lawn mower every spring start up, last year is was stale fuel, this year once the plug was warmed started fine.
1960 Super Rocket, owned since 1966, back on the road 2012 after being laid up for 29yrs.

Offline Duncan R

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Re: Well what a disastrous rebuild this has been
« Reply #4 on: 17.04. 2013 09:32 »
Worth checking your pushrods are in the right place. After I rebuilt my motor I somehow managed to get the pushrods located in the wrong rockers (ex into inlet and inlet to ex) spent days retiming,checking carb and the rest of the checks. After relocating the pushrods it started 3rd kick.

Just a thought - your wet sumping maybe due to the prolonged attempts to start the motor which would pump oil through but not enough go to return it back to the tank. When mine eventually started it smoked like a wet bonfire then returned to normal once the excess sump oil was returned to the tank.

Good luck
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Offline JulianM

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Re: Well what a disastrous rebuild this has been
« Reply #5 on: 17.04. 2013 09:50 »
P***er and we have all been there so don't let it get to you.

What I do.

1. Check spark,
2. Check rough timing of spark, do the points open somewhere approaching TDC,
3. Are the valves on the rock at TDC (just to check roughly the cam timing is close enough)
4. Is the spark on the correct stroke, ie the other cylinder than the one in 3. above
5. Do you have compression, (if it blows past your finger in the plug hole it's enough to run)
6. Do you have fuel in the carburettors,
7. Are the plugs getting wet?  If not then you have no fuel in the cylinders.
7a. If not wet plugs try some easy start, if it runs you have found your problem. Carbs dirty etc.
8. If all is correct, spark is reasonable and at close to correct, compression good, cam timing close to good, fuel wetting the plug.
Give it a push with some mates and see what happens.

I had this when I first got my commando home after I bought it.  Would not start on the kick no matter what you did although 1 to 7 above were perfect.  Pushed it for 15 minutes until it was firing, then it started, ran perfectly and has been a dream ever since!

Good luck.
Julian
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Online bsa-bill

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Re: Well what a disastrous rebuild this has been
« Reply #6 on: 17.04. 2013 11:04 »
Hi bikerboy

My rocket gold flash was similar, it's a big disappointment for sure

A few thoughts to add to Julian's

1. check for spark - a spark at the plug out of the bike is not the same as a spark in the cylinder
2. rough timing of the spark - this is a bit obvious but we've all been caught out with it at sometime - was the timing done with the maggie at full advance?
3. check roughly the cam timing - easy to move from the timing marks when working on the engine," I'll just remove the idler for a minute, then the engine gets turned, then the idler goes back on - doh" (again we've all done it)

reckon the plugs should have been wet if you'd been kicking it over for a while.
the odd feeling is most probably it's just tight, mine was / is the same

Think I might plump for the maggie, only swayed by my own experience as I fitted electronic ignition (Pazon) and itnow  starts just fine, although I have yet to find out what is wrong with the maggie it is going to a member here to get tested when I get time/funds as I do prefer the independence of a maggie

PS I found that my spark was disappearing with the aid of a Sparktune, good bit of kit allows you to see it fire when in the cylinder
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline bikerboy

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Re: Well what a disastrous rebuild this has been
« Reply #7 on: 17.04. 2013 11:49 »
Thanks for all your ideas and just to answer a few questions.

The fuel, brand new went over the local garage filled a jerry can (which was clean) with a gallon of petrol, came back and poured it into the tank which I know is totally clean inside. The carbs have been stripped, float levels checked and all jets and holes blown out with an air line. The slides and needles are both going up and down and even if one carb was a bit dodgy I would expect at least some response on the other cylinder.

The valve timing is accurate, I actually removed the idle gear and retimed it minutes before putting the inner timing case on.

Its got to be something to do with the spark in my eyes and thats a good call on the sparktune idea I think a colour tune is the same thing and I can get my hands on one of those. I do aim to start at step one. Remove the tappet covers and check the valve opening sequence first of all. Check tappet clearances and then I have a bit of a wild idea which might check the mag out.

Its got a 12 volt conversion on it so if I wire up two coils and use the cutout wire as the low tension lead surely that will just make it a coil ignition system ? I can wire both coils together so that I have a wasted spark and if its the mag surely this will prove that one way or another.

Thoughts on that idea ?

I might also nick the kick start of my trident temporarily as its a lot longer and might make it a bit easier to bloody well kick over.

The wet sumping definitely worries me because I filled it with oil probably 10/12 days ago and before I even tried to start it noticed that the oil level had dropped right down, it would of course as most of it was in the damned sump. Muskrat you are right a new ball and spring would not have gone amiss but it all looked fine and the spring was still nice and strong, I really do hope I dont have to strip the damned thing down again to cure that but I will wait until it starts before making a decision on that.

Before I do try the coil idea of course I will check the basics (ignition timing, valve timing etc) but I cant seem to get this odd response out of my mind when I kick it over. I cant even put it into words it just sounds odd.

It is infuriating tho because I have worked damned hard on this and virtually no expense was spared.

Offline chaz

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Re: Well what a disastrous rebuild this has been
« Reply #8 on: 17.04. 2013 12:20 »
If its wet sumped they sometimes are hard to start, I usually leave overnight to thoroghly dry out.
as Julian says , Ive allways got a can of easy start ready. currently working on a non runer Indian Bullet 500. wouldnt start after a cable change. a quick start of easy start and it started, albiet at full throttle...owner had put cable on fully open.

I wouldnt put a bigger kick start on as it adds extra force to the shaft and internals...just my thoughts..
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Online bsa-bill

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Re: Well what a disastrous rebuild this has been
« Reply #9 on: 17.04. 2013 12:30 »
Quote
the sparktune idea I think a colour tune is the same thing

it is indeed, and is what I should have said, dyslexic typewriting
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline warmshed

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Re: Well what a disastrous rebuild this has been
« Reply #10 on: 17.04. 2013 12:37 »
remove the plugs and place your finger over the plug hole turn the engine and make sure the spark occurs as the cylinder comes to compression.

If your sure everything seems right, pull out one plug and see if it will start on one cylinder, reduces the effort, and you can see if the other plug is sparking. Always worth checking this way in case your slip ring is tracking, if so it will start on one cylinder if you remove the second plug.

Offline RichardL

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Re: Well what a disastrous rebuild this has been
« Reply #11 on: 17.04. 2013 12:44 »
Looking at your plug wires, they are on the opposite sides of the mag from mine. My right side comes from the bottom of the mag. Not a problem if that's how you've set it up. Did you recheck timing after tightening down the mag pinion nut (at least my parts book calls it a nut). My own experience is that timing can change a lot if you don't sneak up on tightening that nut.

Richard L.
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Online Triton Thrasher

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Re: Well what a disastrous rebuild this has been
« Reply #12 on: 17.04. 2013 15:00 »
You must have a low threshold of disaster, if a bike being reluctant to start after an overhaul counts as one.

Offline RichardL

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Re: Well what a disastrous rebuild this has been
« Reply #13 on: 17.04. 2013 16:26 »
In rebuilding the magneto, did you replace the capacitor, like from Brightspark Magnetos http://www.brightsparkmagnetos.com/ ? If not, you may as well, since it's cheap and easy to do and will very likely improve your spark, which won't hurt, even if that's not the problem.

Richard L.
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Offline metalflake11

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Re: Well what a disastrous rebuild this has been
« Reply #14 on: 17.04. 2013 17:08 »
If you are confident everything is set correctly, I would follow Billy's advice and heat the plugs and then try it. It's worked for me before now.
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