Forum

[Mike Barker]

Hi everyone
Recently I was reading another forum regarding Bullet crankshafts and there was mention that two different crankshafts were fitted to Indian bullets (light and heavy weight) The heavy weight being fitted to pre 90s engines and a lighter crank being fitted to post 90s and then reverting back to the heavy weight crank in the UCE. along with this was mention that the Redditch had a heavier crank than Indian manufactured bullets.

My question is; does anyone have any further information regarding the differences in the crankshafts weights and to the English and Indian crankshaft flywheels .
Also is it possible to utilise the flywheels from say a Redditch Bullet and fit the timing and drive shafts from late production Indian crank (post 2000)?

Many thanks
Mike

[stinkwheel]

The biggest stumbling block would be actually finding a used crank or flywheels to build up in the first place. And if you're building a crank up, presumably you'd want a steel conrod. Maybe a needle roller big end?... Turns into a money vortex very quickly and before you know it you've built something nearly but not quite as good as one of our hosts billet flywheel cranks.

[Bullet Whisperer]

The Indian bullet 350's were the ones with heavy and light cranks, the heavy ones being pretty much as per the Redditch ones. I have only encountered one type of Indian 500 Bullet flywheels and these seem much as the Redditch ones, possibly a little lighter but not much in it. The Redditch 500 Fury had lighter flywheels than the standard ones. As for steel conrods and roller big ends, they are reassuring to have, but the plain big ends can last forever with regular oil changes and an uninterrupted supply of oil. Alloy conrods can break at sustained high engine speeds, especially Indian ones, but you can reduce the risk of breakage by polishing them.

[Mike Barker]

Hi Stinkwheel

I understand exactly what your saying, I have certainly looked at both Mr H's stock and long stroke cranks Both beautifully manufactured but my only concern is that they appear to be more fast road/race orientated and I desirer is pretty much the opposite.
And I know that if i was somewhat rite in the head I would do the sensible thing and go out and buy myself a Phelon & Moore model 100 but the only fly in the ointment is I LOVE my old Bullet.
What I wish to try and accomplish is the bottom end torque and the proverbial "Pulling the milkman off your granny" all the way grunt of the Panther but all with in my Enfield.
(I must point out here that she is used for sidecar duty and will always be whist in my ownership)

I can see two ways to go about it , either bore and stroke it or increase flywheel mass (or even better Bore, Stroke and mass).

My only concern is when stroking one of these motors is what is involved in terms of modification and is it possible to still retain a relatively low compression ratio.

[Mike Barker]

Many thanks "Bullet Whisperer"
That pretty much answers my question .

[stinkwheel]

Tricky, because they are pretty low power engines and are really more revvy than most people ride them anyway. They historically don't cope well with lots of low rev thumping about. They peen the hell out of the main bearings for one thing if you lug the motor.


Others may disagree here and be a lot more knowledgeable but I'd make two observations.

The first is that it's probably the wrong bike for this kind of riding.

With that out of the way, I wonder if increasing flywheel mass is the first go-to for improving low rev performance? Advancing the valve timing is probably one thing to consider. Our hosts do a 3-position timing pinnion which is relatively inexpensive. Maybe a smaller carb so you're closer to wide open throttle settings at a lower rev speed? Maybe retarding the ignition timing a touch? Reducing reciprocating mass in the valvetrain is always a good thing. Twin plugs to ensure a full burn?

Lengthening the stroke is another but you're back into the realms of costly custom crank work there.

More displacement = more power and torque. Take it out to 535? You don't have to go for high compression at the same time. I'm not sure if you can source a standard compression 535 piston but you could always fit a spacer plate under the barrel with a higher compression one.

Nuclear option, a diesel conversion?

[Mike Barker]

Hi Stinkwheel
I've tried the valve timing trick, I have twin plugged her (makes a considerable amount of difference) also reverted back to british points/advance unit (which did improve things) fitted a british head and is on a small carb. dropped the primary gearing right down to give the engine an easier life. still pulls healthily with adequate cruising speed.

I think you are totally right cubes make power .

I'm just looking for that little something extra ,that pulling away almost on tickover sort of thing and just a little more up the hills.

Please ignore the blued header, on plug chopping she shows to be running very happily. And if the only side affects is a blued pipe for a return of well over 50MPG at duel carriageway speeds I'm more than happy to accept that.

[Bullet Whisperer]

Try putting your timing pinion on the standard keyway, with exhaust cam timed on the dots. With the inlet cam, do the opposite of what I often do and ADVANCE the inlet cam timing by 1 tooth, that is move it clockwise to put the timing mark 1 tooth below the corresponding mark on the exhaust cam. The inlet valve will shut 18 degrees earlier than standard, the kickstart will feel like you have a brick in the cylinder and you may well be able to pull away in 3rd gear, but your engine will be reluctant to rev much, which sounds like you will be on the way to what you want. As already mentioned by Stinkwheel, your bottom end will get more of a pasting in doing this, though.

[Daiwiskers]

Think the problem you will have is you have a relatively high revving short stroke (for a single)
engine the Panther was a completely different engine !long stroke low revving heavy crank softly tuned almost certainly designed for sidecar use

If you want a softly tuned low revving 500 I would suggest a Moto Guzzi Falcone


Sorry can't help much further Dai

[Mike Barker]

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