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[nordicgloom]

Hey all,

Just looking for some advice regarding my 2001 Bullet 500. I took it for a long trip to Brighton one weekend and found when I pulled over that the bullet spluttered out rather than idling. It started again easy but there was little to no resistance from the kicker and I rode it home the next day but it would still not idle without careful throttle use. I adjusted the tappets and have experimented with different tightness, this does not seem to make much difference. I have sensed a disturbance in the force regarding my clutch recently but couldn't give a concrete reason why, is clutch slip a likely candidate? I also feel a sporadic knocking in the engine when at low idle. It runs great at top end but feels like going up hill at the lower throttle range. I have the 1 day to get the old girl good as new. My mechanical knowledge is patchy but I have a vast array of tools, am adequately gun-ho and have downloaded the holy bible, written word from our lord, Peter Snidal.

If any bullet guru's could impart some likely causes of the fault for me to work my way through it would be hugely appreciated. As it is I am starting with removing the exhaust and opening the cylinder head to see whether it's chocked up with carbon or if anythings obviously wrong. This forums always been a tremendous help.

[Alan R]

Hi guys----------- have you checked that the de-compressor cable has plenty of slack in it ???

[Midge]

With ignition off, turn it over slowly by hand and listen for hissing at either inlet or exhaust on compression. If the valves prove ok, I would be wary of piston rings failing. I had similar problems not long before the piston exploded.

[Norm]

"I have the 1 day to get the old girl good as new". This bit worries me, it is never that simple

[nordicgloom]

Norm tell me about it, using my bullet everyday and fitting it's maintenance into a modern lifestyle has to be the most difficult thing. Ok it does not seem to be the decompressor sadly, I've just stripped it and cleaned it and it returns nicely. Blurgh. Ok so I have the afore mentioned hiss when I kick it through (by hand) under compression. I presume this put's me the piston issue camp? Does this mean it is time to open it up and have a proper look?

[Norm]

Nordie, problem here is there can be so many reasons for these problems and once you start pulling the head, then the barrel and then you find something else all of a sudden you end up having to do a total engine strip.Try a bit of oil down the plug hole and see if the compression comes up a bit.Compression rings may have become a little stuck, this does happen. There is always the threat as previously mentioned that the piston could be ready to let go. If you pull the barrel what you need to check is the oil ring and if it is showing signs of being grabbed in the slot, the piston is getting close to failing and must be replaced. This will fix the top but you also mentioned a noise down lower and the just opens another can of worms

[PeteF]

If you are hearing hissing on compression then it's one of the valves that is leaking. A leaking exhaust or decomp will sound in the exhaust and a leak on the inlet will be heard through the carb.
Did you grind in the decomp valve?

[simon]

Sounds like a burnt valve to me. My brothers 350 did an exhaust valve but what amazed me was that the bike kept going. It had almost no compression on the kick starter and as with yours had a weak idle but it still pulled along and a reasonable clip. The exhaust valve was an oval shape and our hosts provided the replacement in double quick time even though they around 12,000 miles away! The repair shouldn't take too long if it is indeed a valve. Get some grinding paste and a suction cup on a stick as well a top overhaul gasket set and you should be back on the road in no time.

[simon]

It's also possible that the knocking is pre ignition from the burning edge of the valve although ill admit this is the optimist in me talking. If your pulling off the head you might as well take a look at the piston at the same time, its only one extra gasket and it could save you a lot of misery.

[nordicgloom]

Norm you were dead on, I have secured the loan of a car and settled in for a long week of Bullet time. I had some unconnected fears about it being a bit coked up so I went ahead and removed the cylinder head and barrel.


This is heavily unchartered territory for me I have to say. So I have sanded the carbon carefully from the piston and checked the bore. So far so good, The piston rings look ok? Sorry to sound so green but Norm when you say 'grabbing', do you mean as in it moves freely in it's groove? There aren't any suspicious signs from the piston though and it was relatively easy to strip so it's an education and a relief.


So we're back at leaky valves? Pete F I didn't grind the compressor no but I have the head off so I guess that's recommended?


So as it stands I am going to clean the carbon off the valves, watch youtube videos about piston rings and compressors. Any others nods toward obvious folly's to avoid or places I need to inspect are so hugely welcome, I literally struggle to express how new all this is to me but I am having a hoot doing it.


Thanks boys