Hitchcocks Forum

MY 2004 500 SPORTSMAN, HITCHCOCKS MIKUNI CARB FITTED WITH BELL MOUTH, STRAIGHT THOUGH EXHAUST AND 18 TOOTH GEARBOX SPROCKET IS STILL UNDER GEARED SO HAVE NOW FITTED A 20 TOOTH SPROCKET. NOW THATS MORE LIKE IT, I CAN REALLY MAKE GOOD USE OF THE 5 SPEED BOX, IT STILL PULLS VERY WELL AND I FIND NOW I DON'T RUN OUT OF REVS SO EASY. THE BIKE IS MUCH MORE FUN TO RIDE NOW.
JUST THOUGHT IT MIGHT BE OF INTEREST.

Thanks Johnny. I have a 625 with a 19 tooth sprocket, and I've been thinking about trying a larger one. If yours goes well with it, then mine should cope. btw, what size back wheel/tyre do you have?

Hi Johnny, this sounds like fun to ride. I'm intereted to hear how you have the Mikuni jetted up?

HI Allan, it has the standard 19in rear wheel.
Al, sorry I cannot for the life of me remember the jet sizes that I used in the Mikuni but it is very smooth from the lowest tickover to full throttle with out the hint of a hickup plus the exhaust is a lovely straw colour so engine is running at the correct temp so jetting must be right as is the ignition timing. using points as appossed to electronic ignition as when set up correctly they work very well.

Back in my single cylinder (Ducati & Aermacchi) class racing days we used to change the rear wheel sprocket to suit the particular circuit we were racing on ie., for higher top end or acceleration. One never ever changed the gearbox sprocket. Are there alternative rear sprockets avilable for our Enfields? After all it's a simple enough job to drop out the wheel and change the rear but a right pain in the ass to change the gearbox cog.

Hi Eddie. Our hosts do a conversion of the rear sprocket allowing larger ones to be bolted on, but not smaller (which you would need if gearing-up.) I assume that it's deigned for off-road use. It looks like the only option for gearing-up for road use is to fit a larger gearbox sprocket.

Hello A/L EDDIE ---------- Yes, I'd do the same on my grass-track bikes. But then they had what I might term "normal" rear wheels ie NOT like the standard Enfield idea of having the teeth cast-in as part of the hub. As my other namesake says you can get a conversion kit from Mr H but if your Bullet is still in "as supplied" road gearing then most agree that a change up by one tooth is required in any case and then should be regarded as "Standard". So taking 18t as the start point---19t now becomes your first upgrade size (say for an up-jetted vm28mm carb. and appropriate exhaust etc.) OR you can go to the 20t and again with the appropriate exhaust & carb. have the results that JOHNNY SINGLES is having. BUT }}---- that's all based on the rear sprocket as fitted. If you now fit our hosts kit then, as my mate says, you can only fit BIGGER sprockets --- thus undoing the previous efforts. Alternatively----you could source another make of wheel assy. where fitting SMALLER rear sprockets is possible. I agree entirely with your comments about the "Rectum Sensation" associated with the change of a gearbox output sprocket------------- I'm typing this letter because I'm putting it off this morning. SHAME on me !!! Be seeing you---------