Hitchcocks Forum

Hi all, I need a bit of advice from you experts. 2006 Bullet 350.

I've just taken the cylinder head and barrel off to investigate some piston slap, oil use, reduced performance, high fuel consumption, etc. Turned out this was due to a gudgeon pin circlip having come off and grooved the barrel and piston.

While I was there I checked the big end play. There is no up and down play, but side to side play is 2-3mm, measured at the top of the conrod. The manuals say "some" play is acceptable, but not how much. Is this amount of play acceptable?

Thanks

Ed

Sounds ok. While you're in there, do take the time to check the small end eye, these can crack but ovality is probably the first sign. Having said that, 500s are more prone to this than 350s.
REgards, Mark.

I agree with Mark - 2-3 mm side to side play is fine.

Mine is deemed passable and has more play, see it in this video and compare to yours.........................http://www.youtube.com/watch?v=DzjmvmxiZKg..........

Hello ED LAZDA ---------- You say it's 2 to 3 mm ( approx 1/8") at TOP of con rod ?? Given the length of the rod and it's magnifying effect then those measurements are naff-all, eh ??... Even if that were a lateral or side movement along the big-end bush its' no great shakes for this floating bush set up... I'm in agreement with the others here.... PS, for those NEW to engineering that terminology of "naff-all" means}-- "zilch, zoddall, nowt,!!"---- ie minimal.

Thanks all. The list of jobs to do has been getting longer, glad that one doesn't have to be added as well.

Hi ED, --- lucky you !!!I bought my No.2 Bullet and rode it home from Hampshire during the Summer----Lovely bike, running well with the 4-speed gearbox leak-free and nice, crisp changes. BUT--- it had that tell-tale smoke in the exhaust after the over-run with throttle shut--Yes, it's going to be a head-off job and new valve guides. OK---no probs.----I have a spare head just for this moment...Off came the head, easy peesy....Too easy !!! I always pop the barrel off as well at this stage for a quick look-around....alas the small-end(wrist pin) had been bronze bushed at some stage in it's career and now this was coming loose !!.... The wall-thickness at the little end is now only 2-3mm with a hole that's clearly oval......So a new Con-rod is needed..... I had considered putting a 5mm steel strap over the top and bolt it on, but gave up on that as potentially unsafe. So it's an engine out, strip,new con-rod assy. and anything else that might show it's ugly head !!! YEP, That list of jobs just gets longer ------- AND longer !!!!!! Ah well, give me something to do in my wet,retired days ahead !!!

Ed,
my concern is to why the circlip came out, it is often caused by side pressure on the gudgeon which indicates crank not happy

Norm, I did wonder why the circlip came off. Apart from the big end play, is there anything else I could do to check this out without dismantling the engine? Must admit I'm a bit reluctant to do that on the off chance -- and I will of course regret this approach when it collapses into a heap of distorted alloy in 2300 miles time.

Ed, have a very close look at the groove that the circlip came out of and if there is signs of damage to the groove then I would say the rod has been forcing the gudgeon sideways