Forum

[Bullet Whisperer]

Just a few weeks ago, I had a Bullet engine making those sort of noises and in my case it turned out the worm nut wasn't very tight against the timing pinion, which was in turn not very tight on the key. As the cams went over their full lifts, the small amount of backlash in the pinion caused the clacking noise. Tightening the worm nut stopped the noises, after checking the small timing pinion key was ok. Cheers, Paul.

[Norm]

Got caught with one a few years ago after I fitted a set of Ace cams, the tip of the exhaust cam was clipping the boss around the seal on the timing shaft

[ChrisD]

Gentlemen thanks for all your input.
Tim - Yes, For the past ~1000km I’ve been able to ride it up to half throttle but not beyond because it misfired badly. After much coil and plug testing, this misfire is clearly not electrical or ignition timing.
Also after much more testing, the misfire is proven not due to either set of cams (OEM or H’s performance #200180) or the adjustable pinion position.
So far it seems much better since I changed the Amal Mk2 slide to a 2½ but still not quite right (I had to fit a new carb because, at some time in its previous life, the threads on the Mikcarb mixing chamber had been crossed and only 2 were barely holding). Not jet related (tried so many of them, including the air jet) – perhaps a hundred plugchops over the past year of testing.
I avoided one set of issues coming from over-compression (using Mr.H’s forged high comp 535 piston) by adding plates (without plates the static compression reached 175psi). Once the misfire is resolved (almost there) I’ll get the compression right.
Our best petrol here is 95 octane – have tried various additives with no evident success.
So, sequential testing and lots of it is the best way – hence the many kilometres.

There are different size crank pinions – you mean cams?

Mauri – good point, checked and OK (new pushrods fitted, Mr H’s stiffer ones).
BW – hmmm, good point about the worm nut – I will check that and also the key fit.
Norm – yes checked the performance cams were free of contact by wrapping them in ~20thou of tape. Grind casing away where the cams touch so that they can spin freely with the tape on. Once the tape is removed, there can be no contact (got this suggestion from this site a while back). Also 5thou shims behind cams to separate them from the casing.
Leon – yes, I’d heard that Samrats were noisy. So once the misfire issue is resolved, I’ll look into trying the originals out again (suitably drilled for max flow and with good oilway contacts).

Has anyone actually seen the video on Photobucket (chrisd200, Library, Bullet Cams)? I’m sorry if you cannot see it here. Photobucket shows it was the correct html. On that video there is no doubt that the noise is related to the maximum valve openings, so I believe the noise is related to cams. The question is “is it so bad as to be a issue or not” and the answer seems to be “live with it or get new cams+spindles”.
ChrisD

[Norm]

Chris I haven't seen the vid but new cams and spindles won't solve whatever it is

[[email protected]]

Hi All good morning. Great people and great message. Useful. I have one quick query. I am trying to restore my 1962 350 standard and CAM SPINDLE and backlash is a issue here. I installed OE CONCENTRIC (NON ADJUSTABLE CAM SPINDLE) bigger size to match my timing case cam bore, bored to right size and fitted. My problem is that the cam wheels are not rotating freely which is OE NEW. It was so tight to rotate with fingers. But i am able to get them alligned all wheels, checked the center to center distance between the cam spindle. Checked in professional turning shop and no help. Will that be a issue in starting the engine? It should not break the gears is my wory because the OE wheels are expensive. Or is there any suggestion to improve the rotation or is itfine to have like that tight. People are saying it will be alright after few kilometers and is it true. Thans and appreceiating ur early respinse and expert advise. Thanks all. Great day

[vince]

Hi, My 500 had a misfire which was cured by closing the plug gap,it proved very critical and a few thou made the difference. Vince. Ps do the cam followers have any wear as they will cause clacking!