Hitchcocks Forum

Well I'm now truly flummoxed. I have stripped the motor right down to the extent of splitting the crankcases. The crank and bigend looked and actually sound fine (this isn't a big end noise). I previously had the valve guides and seats replaced and replaced the rockers. The piston is fine and in a nice new alloy barrel. I've checked and tensioned the primary chain and the clutch has had considerable and oft mentioned work. Yet after a short fast run the intermittent clanking starts again. It sounds like a sticking valve except the idle is perfect so ALL IT CAN BE is gearbox although what would make that noise in a gearbox is beyond me. I might dismantle it this weekend if the wife will do the garden and see if there is a foreign object floating around in there.

My Electra X had a clanking noise shortly after I rebuilt it. It turned out to be the nut on the crankshaft that holds the primary chain sprocket was slightly loose tightened it and all was fine.

My Bullet had a clanking noise, the machanic removed the Samrat rockers and replaced them with the original ones, no more clanking.

Simon, nothing in a gearbox to make a clunking noise

A problem is very often caused by the last thing you did. Trouble is, we all tend to think "it can't be that because I've dealt with it">br>So, was the clank there before replacement of the valves, guides and seats?
If so, was it done properly?

Perhaps after a fast run, when the head is at it's hottest, the guides or seats are moving?
Try sticking the head in an oven then seeing if everything is OK

Hi Simon,
Take a good close look at your alternator rotor, it could be the body coming loose from the core - check for backlash by trying to rotate it each way by gripping the outer circumference - ditto a sloppy key or keyway, or even the magnets trying to break out and tapping against the stator. I had a 350 Bullet brought here once for a total strip and rebuild to fix a worn out big end, the owner was very happy to find out it just needed a new alternator rotor instead !
Regards, Paul.

When my Bullet had a persistent clank (not a clunk or clink) recently, it turned out to be the chain slapping on the chainguard, because the front sprocket was worn.

Mmm I'll have a look at the rotor BW. I don't believe it is anything that I have done as it made the noise when I fired it up on the bench years ago now. Very weird intermittent clank. It does seem to be slowly getting louder so I must be coming to a denouement. I replaced the original rockers with Samrats as the old ones had worn quite badly and would get quite stuck in the oil way groove at the top of the rocker. Horrible design I thought. Samrats seem fine but with em or without em the noise is the same. I posted a vid of it making it a while back when it still had an iron barrel. I'll see if I can fine it.

Oh and Pete, I thought it was the valve seats last time so had the head rebuilt with new seats and guides. Same noise no change.

http://youtu.be/EOC1a3zPQm0
This is it. Note the idle is even. I'll definitely take a look at the alternator rotor but I've not seen any signs of it polling.