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[jawa-enfield]

Hello all, could you help me reflect about the following matter?

I have a '94 500 bullet, maybe it was an 'inland version' because wow, it had some serious quality issues..
I overhauled everything, has now electronic ignition, flowed head and a 30mm carburettor and with the 18T front sprocket it has still good acceleration in 4th gear.

A safe cruiding speed on the Dutch B-roads is about 90km/h.

If... i replace the 6,5 piston with the 8,5 piston,
1- will it raise performance enough to mount a 19T sprocket and maintain pulling power in 4th? The goal is to have a 'healthier' lower RPM at 90 km/h.. Right now the revving scares me a little..

2- Will it strain the engine considerably more (Should i not complain if the crankshaft wears out soon/breaks down?) and/or should i mount a 'bigger' oil pump and doe work on the oil ducts first?

In other words, is it more sensible to leave it the way it is and be happy with a fully functioning bullet?

Thanks!

[Adrian]

What I would suggest is that if it's working well at long last, LEAVE IT ALONE!

You can always start building a replacement engine at your leisure for when your current engine finally needs major work. The replacement engine can be built up to the specification you want with the go faster/hold together longer parts.

I don't know what sort of revving scares you, but a 500 Bullet in good condition ought to be able to cruise at 56mph/90kph for long periods with no ill effects. If you start thrashing the thing you might reach the outer limits of the alloy con-rod's tensile strength, but I gather those 500 Bullets which have thrown a con-rod have usually been subjected to higher revs than yours will have for the conditions you describe.

Don't forget that "lugging" the engine, i.e. not giving it enough revs for the traffic can damage the engine too.

You mention that the quality issues you found suggested it wasn't an official export bike. This is quite possible, quite a few home-market bikes have been privately imported. The 500 transfer on the toolbox lid was common on home market 500s but not on export versions.

A.

[Daiwiskers]

As above

If it ain't broke don't fix it

If you do try to fix what ain't broke you may fall down the rabbit hole of fixing it till it is broke!


There's a old saying in the UK " let sleeping dogs lie" I think this applies here

[stinkwheel]

I wouldn't expect it to pull 19 teeth in top without a significant amount of tuning.

Enfield bullets are comparatively revvy bikes for singles so don't worry about it.

FItting a bigger pump increases the oil flow rate, not necessarily the pressure. If it's being pushed hard, this will help with cooling. In general, it can also help increase burning of oil. I took the high flow pumps off my 350 bullet. They were unecessary and I'm pretty sure they were increasing oil consumption by filling the rocker area to a higher level.

[Wheaters]

18 teeth is already one tooth higher than standard gearing for a 500.
It might not sound like a large difference, but it's significant because there's only 38 teeth on the rear sprocket. Raising it further would be approximately 11% "taller" overall.

This would also effectively increase the differences between the intermediate gears by 11%. That gap between 3rd and 4th would certainly be felt.

I wouldn't worry about revving the Bullet engine, I don't. My 350 is on 18/42 tooth gearing, which is very close to standard for a 350 but lower than your bike. It revs very hard for a living, especially since it now has 5 gears. I timed the bike over a known distance on the M1 and it averaged 71 mph:

https://www.youtube.com/watch?v=If47Pnkgfrs&t=70s

[Duke of Wybourne.]

Leave it alone. For country roads a top gear bike is best. Going up a cog, and you'll be playing tunes on the gearbox all day.

[Vince2]

Hi, the 1955 road test of the 500 refers to cruising in the upper 70s and the tester was of the opinion that the bike could do with the gearing being 'lowered' for everyday use. What is it that concerns you when cruising faster? Vince

[Vince2]

Hi, the 1955 road test of the 500 refers to cruising in the upper 70s and the tester was of the opinion that the bike could do with the gearing being 'lowered' for everyday use. What is it that concerns you when cruising faster? Vince

[jawa-enfield]

Thanks guys! i think you are all right...