Hitchcocks Forum

hi, I have this problem on my bullet 350, year 2008; when the engine is hot, there is a noise coming from the head, which seems to be valves, but stronger and intermittent. as soon as I turn off the bike, then I turn it back on, the noise is even louder, and it can also be heard when the engine is off (warm) by operating the kickstarter. advance and carburetion ok, motorcycle runs 6000 km, oil almost new .... what do you think? I understand that it is very difficult to explain in words ... thank you

the bike has an SB filter and an open exhaust

Loose valve seats?

My god.....I hope another cause....

The valve seat fell out of the original head on my 2007 350 bullet. Ran with it flapping about in the breeze for about 6 months. Mine did an inordinate amount of popping and banging when going downhill on a closed throttle while that was going on.



However, I'd check your tappets when it's hot for one thing. You can also use a bit of broom handle/large screwdriver with the rounded end held against your ear and the other pressed against parts of the engine as a kind of engineers stethescope. It can give you a much better idea of the quality and location of the noise.



You can also get some odd clattery noises from induction or even from backlash on the cam gears which may become more apparent as the oil gets hot (and therefore thin). Small exhaust leaks can also make some odd noises.

Worn rocker spindles ??..They can sort of twitch sideways when really worn....probably the exhaust one due to the extra heat nearby...Valve spring seat retainers ?........From your description it certainly seems to be a fault associated with the cyl. head...........If you can afford to get another head--- re-con it and then do a swap-over.....At least the bike won't be off the road for any long length of time....Do our hosts have anything suitable in their "used parts" range ??

Maybe worth checking that oil is getting to the rocker gear by slackening a banjo bolt on the external oil pipe and kicking the engine over (easier with spark plug out).

Hi,oil its ok,rocker it seem good,now I coninue my check....but I got new cylinder head.....

Before this 2008 bullet, I had another one, again in 2008, with very close chassis numbers. In the first bike, I had the same problem: after a few months with these noises, I saw the detachment of the exhaust valve . So I think: maybe the cylinder head of that year had problems ??