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[stinkwheel]

This is on my 2003 612 converted pre-unit bullet.

I have a crank mounted ignition which has rendered the whole distributor mechanism redundant. The casting has been removed and the opening blanked off.

When I first assembled it, I left out the two idler gears that normally run between the inlet cam and the distributor drive shaft on the premise that they were just unecessary mass.

Thing is, I get a low rev clattering noise under load. It goes away at higher revs and I'm not particularly in the habit of riding it about at low revs anyway. I'd initially suspected it was pinking but now I'm suspicious it could be cam balcklash. I'd pondered fitting adjustable cam spindles when I built the bike and decided against it on the basis that while the standard ones can't be adjusted tighter, neither can they come loose.

I'm now wondering if the mass of one or both of the idler pinnions might serve to have a damping effect on the cams?

I'm going to try Bullet Whisperers inlet cam retarding trick which should make it a bit softer at lower revs anyway? I was wondering if anyone has any thoughts about fitting one or both of the idler pinnions at the same time?

[Wheaters]

My 350 Bullet Electra never had idler gears and it’s quiet enough. I would have thought that the fewer the number of components making noise and sapping the measly output of these engines the better.

[stinkwheel]

Although power output is less of an issue in this instance.

[vince]

Hi, check the tappet blocks for play. Vince

[Blown265]

Gday SW

Refitting the two small idler gears will make no measurable difference in performance- in your case they're not driving a load, and even on a dyno would show no indicated horsepower loss.

What they may do if reinstalled, is offer some small counter balancing harmonic, and smooth out the cams' motion. Thats a big "may". The test is simple enough.

Which cams are you using- #90023 or #200180 ? I wouldnt be moving either of these (inlets) as far as one tooth. The adjustable pinion gear #90008 shifts the rev range a few hundred rpm, but be very careful with v/p clearance.

Regards
Paul

[Bullet Whisperer]

Retarding the inlet cam moves the inlet valve further away from the piston, so no worries there. 1 tooth is 18 crank degrees, which seems a lot, but it works. Beware if you use a 3 way pinion, some have a 'retarded' setting which is actually more advanced than the advanced one, thanks to the timing mark being 1 tooth out ...

[Wheaters]

My Bullet 350 Electra was “born” without a distributor or timing pinion gears. The timing case, apart from the cams, has always been empty.

I doubt that leaving them out makes any reduction to vibration via harmonics. If they’re unloaded they will be damped due to being immersed in oil and not really attached to the drive from the cam. They are probably able to chatter and are surely more likely to cause vibration /mechanical noise than to reduce it.

[stinkwheel]

I've gone halfway and fitted one of the idler gears. There has been talk in the past about this one helping with oil return to the tank too.

First impression with the inlet cam retarded a tooth is that it idles a lot more steadily. Engine did not blow up. Road testing will have to wait for the MOT.

[Bullet Whisperer]

The idler gears are a requirement for oil returned from the timing chest to the oil tank on British engines, but Indian engines do not have the close fitting, machined face behind the idler gears to enable this. Instead, they just have a bigger hole leading into the oil tank from the timing chest. No harm will come to any engine by retarding the inlet timing - advancing it is the dodgy one. You may find the engine is easier to kick over and start and less likely to pink under load, if it ever did before.

[stinkwheel]

You may find the engine is easier to kick over and start and less likely to pink under load, if it ever did before.

That would be a win then. I'll see how it goes out on the road later in the week.