Forum

[simon]

Pulled the bitsa apart last night. Had the motor and gear box out of the frame in just over an hour. Then another half an hour to remove the g-box and the chain case. ten minutes more and the head and barrel were on the floor and it was time for bed. The issue is clearly something to do with an end float of around 5/16" which int right. I'll split the crank case this evening and reveal all the internal horrors. will report back then.

[simon]

Ok deeply confused again. The crankcase is split and apart from a fair amount of sludge in the bottom of the oil tank there was no sign of anything wrong. I established before I did the split that the end float was only about 4 to 5 mm rather than the 8mm I'd assumed it was and this was without the sprocket and alternator rotor attached which I now assume are involved in setting the end float. There was a considerable sign of blow by and the piston was show signs of having been a bit scuffed which would lend credence to the excessive end float theory. I have yet to pull out and examine the main bearings so will report again then. However if anyone can let me know what sets the end float and if it is held by the outer bearing on the drive side I would be appreciative. Cheers S. it's a 1992 350 btw.

[Bullet Whisperer]

Hi Simon,
There should be no end float with the alternator rotor nut done up tightly, as these drive side components serve to lock the driveside mainshaft and crank in position, the centre plane of the conrod should also be central to the crankcase joint with the rotor nut tight, if not, shimming can sort it.
You should have a small amount of end float with the rotor etc loose or removed, but probably only around 1 - 2 mm at most and that is providing you can slide the driveside mainshaft side to side through the main bearings, which is often not the case as they can be a very tight fit.
Paul.

[simon]

Cheers Paul, as I suspected then the drive side locks the whole thing up tight. I'll pull all the bearings out and see if I can see why there was such a lot of movement.
S:)

[Norm]

Simon,
Thinking about it the only way I can see you having any end float 4mm is massive is the distance piece ring is missing between the drive side bearings. I'm not sure if it could go together without it but that is the only way you could end up with that much end float

[simon]

Nothing wrong with anything in the bottom end. The bearings are fine, the end float with the spacer in place and the sprocket and alternator tight is non existent. There was nothing wrong with the oil pump and nowhere was there a source of brass swarf or a cause or a witness of a clatter. So back together it goes and I guess I'll get used to the intermittent noise.

[Bullet Whisperer]

Hi Simon, good news then. Bullet engines [and some others] are pretty good at spooking you with noises, if you let them. I found my bikes improved overnight with the purchase of a new helmet!
Cheers, Paul.

[Norm]

Thats great news Simon, so if you aren't too busy could you slip over here and give me a hand with this dam Chang Jiang All that happend to it was the head broke off the rotor bolt that in turn hit up against the left conrod and buggered the big end and while all this was going on it locked up the rear wheel and busted the gearbox

[Alan R]

Hi guys--------- Oh dear NORM !! you don't do things by half, eh ??..SIMON, I'm not aware of the earlier part of this story but, now that you are about to re-build the engine why not take the opportunity to fit European-made main bearings ??

[Mark M]

When this thread first arose I said to Simon if the weather was good I'd just get on and ride the bike and how tough these Bullet bottom ends are. I wasn't being flippant, my suggestion came from previous experience of a situation like this. I agree it's not easy to diagnose by Internet but we do learn a bit as we go along... REgards, Mark