Hitchcocks Forum

Bullet Gearbox Sprocket Change

Hi All
I am about to change the gearbox sprocket on my 2004 Sixty 5 500 bullet and as I am still riding it regularly I want to assemble all the tools needed to cut down the off road time. I have read our hosts instructions for doing the work on a 4 speed box and it seems to be the same for my 5 speed box. So for the tools__________
I can make a clutch center extractor……………. For the gearbox nut I have some large box spanners but I don’t know the size across the flats for this nut. It is a 5 speed gearbox. Does anyone know the size?
The clutch holding tool----- is this absolutely necessary or can you just stick it in gear, put back brake on and undo the nut or is there any other way of doing it. I have the tool for locking the clutch on a Triumph T100 unit construction but I assume this would be a different size.---------------------- (2) I’ve done the biz with S&B filter, uprated jets, and sports silencer so what’s the opinion from you knowledgeable blokes out there as to what is the best size sprocket. 18 or 19 tooth. I’ve got a good Exel sheet that can be altered to show that 18 tooth will give an about 3 mph, and 19 tooth about 6 mph at 3,400rpm at between 50 and 60 mph ……………………Regards Freddy

50mm across the flats is pretty close,

Hi FREDDY W----------- I went down this same road a few years back with a Bullet 65. IMHO the 18T is what should have been fitted as standard anyway so regard that as the starting point---- I went for the 19T as I had a lot of "Baggage" carrying to do at the time ( you can work that one out for yourself !!)----- As you are using the whole uprated package on your bike then I would fit a 20T ------- your 5-speed box giving you a bit more flexibility for the "iron" engine than its' 4-speed cousin does. A simple clutch locking tool can be made by a pair of scrap clutch plates (one driver, one driven ) and have them tack-welded together. You should find that your comfortable cruising speed will have shifted up a bit. Be careful to centralise the mainshaft oil seal holder when re-assembling, and use a sleeve of some sort to protect the seal lip........ Our hosts supply a plastic shim sheet for getting the clearance correct between the alternator rotor and stator............Take the time to check-out the routing and condition of the clutch cable. I believe there is a mod. part for where it enters the rear of the gearbox ?? Check the pivot stud for the primary chain adjuster, it has a habit of coming loose. -------Consider using ATF oil in the primary case ( It worked OK for me, even with the Electric start, sprag etc. ).......Have a nice day !!!

Hi Norm, Thanks for that, I think I’ve got a 2”box. I hope your summer is going to be better than ours was…………………………………..Hi Alan, I think I'll go for a 19 Tooth that will be plenty for a first try. As for a clutch locking tool I have no old clutch plates, so it’s either buy new set of clutch plates or the tool from our hosts. As for your other suggestions, yes including lip seal protection.………….Regards Fred.

Freddy 19 should be best.. The Indian method to undo the rotor and clutch hub nuts is to jamb a rag between the clutch sprocket and chain. People may freak at this but relative to the forces applied when dropping the clutch the force your arm can apply is only minimal

And Freddy, nice day today top around 28C going for a ride up into the hills for lunch

Freddy - the three countersink allen screws that attatch the inner primary case to the crankcase can be a bitch to slacken. I couldn't shift mine with an ordinary allen key, and didn't want to risk chewing the screw heads (and cause a bigger problem!) so I ordered a hardened 5mm allen key "bit" (with a 10mm hexagon head) off Ebay. Also, to maximise the the depth the allen key went into the screw head, I ground the chamfer off business end of the bit first. It worked a treat using a 10mm ring spanner.

Freddy - Norm's Indian method of jamming a rag between the clutch housing and the primary chain didn't work for me as the built in 'flex' wouldn't crack open the nut (so to speak). So I locked the primary drive with two tommy bars - one placed between the engine sprocket and the chain and the other between the clutch sprocket and the chain. It sounds a bit back-street but the sprockets and chains are so hard they won't suffer any damage. You can use the same method to retighten the nut later. Cheers. Tony.

Tony and Norm I’m sure one way or the other the damned nut will be undone………………………………..
Barry, Thanks for the heads up about the countersunk allen screws, I’ll be careful……………..
Regards Fred

Norm You know how to hurt people!!!!!!! I went for a ride yesterday down off the hills and sat outside a nice little café on the bank of the canal in Stroud having coffee and a fag with a gelded brass monkey. The temp was just less than 5 degrees. It’s 1 degree today and snowing, I think I will stay in……….Regards frozen Fred