My Daily Rider

[Worty]

Cheers Swarfy, I'll take your reassurances and consider Berger's kind offer.

Thanks again everyone!

[Worty]

Thanks SHM.  Does sound like a clonk, but runs majestically.  I've had the primary an timing sides off, and you can reach the crank with the sump/gauze of and move the crank sideways. The lateral movement on the timing side is slight, but no up and down movement.  Since I fixed the timing back at 11/32 (8.5mm), I don't have the 'clunk' revving from idle, and the bike runs through to 60mph in third (with needle raised to P4).  Can't fault the running, but worry about something collapsing big time.

I'm guessing crank shimming means a complete engine stripdown, or is there a magical way of doing it using the dark arts (Bergler???).  Given that the gearbox sprocket is only accessible by removing the inner primary, I'm guessing BSA would have made it a difficult as possible.

[Greybeard]

I'm guessing crank shimming means a complete engine stripdown, or is there a magical way of doing it using the dark arts (Bergler???).  Given that the gearbox sprocket is only accessible by removing the inner primary, I'm guessing BSA would have made it a difficult as possible.

It cannot be done with keyhole surgery, it's open chest heart surgery.  The strip allows you to flush out the sludge trap and check camshaft and followers as well as bottom end bearings. 👍

[Worty]

BUGGA!!

[Swarfcut]

 No need to feel that exasperation. These engines are simple for a fella like bergs, and his offer I am sure was made in the light of the work involved. Yes, it's an engine out, barrel off, cases split job.

 The upside as GB notes is a good chance to delve deeper and clean and check the vital bits, and the more I think about the intimated history I reckon there may be a few surprises.

 My guess is whoever nailed it together probably took a guess at the shim pack, or even left them out. I can't recall if this engine had a loose crank nut, shims ground to slivers and found in the sump, but it has such a convoluted history as expressed on the Forum over time that I can't keep track. Maybe I'm dreaming.

  Things to consider. Wear or excessive running clearance on the timing side bush is shown by a distinct up and down movement of the crank. You'll be able to move the crank with a lever between the oil pump and the drive worm. By the description this is all fine. Crank endfloat is the lateral movement of the crank between the timing bush and the drive side outer race. There has to be a lateral clearance to allow the crank to rotate, and this is set to the workshop spec. by circular shims fitted between the crank web and the drive side roller bearing inner race. Getting this right is the tedious part, all detailed in earlier posts on the art of crank shimming.

 The crank will not go bang, but it is a lot of metal moving sideways and to echo SHM, a small  movement gives a big clonk in the quiet of the workshop. Once up to speed, the oilpump drive tends to stabilise the crank.

 

 Swarfy

[Worty]

Right, that's it, not going to worry any more and just ride - thanks Swarfy and everyone.

Bergs - thanks, and watch this space.

Maybe not being used to the vagueries of British iron, and their particular peculiarities, I'm measuring what I see against Japanese and German engineering.  I'm assuming BSA used different benchmarks??

I know you'll all understand my concerns, having probably been there yourselves a few times, but I've a lot of blood, sweat, tears and FUN invested in the old gal, so want to keep her running for as long as possible.  I've decided to keep her!

[berger]

and sing --worty don't worry about a ting cos every little ting gunna be alright .   i rode my betsy for 100miles two up from silverstone to chesterfield with a snapped crank, i only noticed a change in the engine note and a few noises i had never heard before so i stripped it at daft o'clock when we got back and the crank fell out leaving the timing side web still in place   i put the pictures up ages ago. yes these old crappy/ well engineered engines back in the day can handle some out of tolerance factors, i can't see my urma yonda 750 running with a snapped crank or a knackered timing chain tensioner 

[Worty]

Jeez, a snapped crank, makes my issues look like a picnic.  How the heck can it run with a snapped crank??

Anyhow, I apologise for the hysteria over a bit of play.  Maybe I'm more disappointed with the rebuild, it should have been better than it was.

Kwaka is still on its way though.  I like the thought of having two bikes again, and I think Sue would prefer the Kwaka than the A10 on longer trips - less risk and vibration!!

[Worty]

Thanks SHM, more disaster stories to follow.

Funny actually, soon after I joined the Forum, someone suggested I change my username to Worstluck - I think he had a point.

I shall regale you further with tales of woe in due course, and for your good humour of course!!

 

[berger]

worty this is the crank web that stayed in the timing side bush when i pulled the cases apart because the oil pump and nut were still fastened, and yes it was still running untill i took it apart late at night after the journey home.

[Worty]

Holy Cow, Bergs.   I've heard about getting home on a wing an a prayer, but this takes things to a whole new level.

[berger]

worty before it started rusting you could see where it was rubbing the snapped surfaces smooth.

[Worty]

Quick regrind Bergs and it'll be as good as new.