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[Blown265]

The end result:

[Blown265]

This is the engine bolt SW mentioned. Here, it was installed flush, and gently profiled to give clearance. This was with a previous 20T sprocket, so a 22T will likely need the same treatment.

[Andy C]

Many thanks to all for the pictures and advice - I know what to look out for now.

Just have to get the other bike finished before I get the Bullet "on he bench".

[Wheaters]

Hi Andy,
In addition to SW posts, the rear mounting point may need attention as well.
Before:

I've literally just fitted a 5 speed box to my "iron" Bullet. The 4 speed doesn't have a spigot like this one in the photo....so what does it do?

Does it locate the rear end of a different type of inner chaincase to mine? There's nowhere it can go on my bike so I plugged it with a cap screw and some Loctite. I realised when refitting the inner chaincase that I needed to ensure that it was carefully positioned so the gearbox input shaft oil seal in its holder was accurately centralised because the rear of the case isn't positively located.

[Blown265]

G'day SW

I haven't seen factory literature outlining its purpose, but to my mind, it's as you suggest- an alignment locator for the the inner case. Adding stability to the rear is a plus.

Mine was originally an electric and kick start bike, so the primary case has provision for the starter motor, and perhaps is slightly different to yours. (the bike is now kick start only due to the cost of sprags delivered to Australia)

Regards
Paul

[vince]

Hi, assuming your other sprockets are standard size, with a 22t gearbox your top gear will be 3.86 which is taller than a 750 interceptor. Now with a standard rear wheel 70mph will equal 3500rpm. Which with performance cams means you will not be in its revband. Vince

[Wheaters]

Perhaps the starter motor is the clue. The torque reaction it would place on the chain case would need to be catered for. Without the rear support the case would tend to rotate around the circle of screws holding the front end.

[Andy C]

Hi, assuming your other sprockets are standard size, with a 22t gearbox your top gear will be 3.86 which is taller than a 750 interceptor. Now with a standard rear wheel 70mph will equal 3500rpm. Which with performance cams means you will not be in its revband. Vince

Got me thinking now - with my current setup 19t gearbox / 38 rear it has a good turn of speed and if you take 5500 RPM as being the top limit for the performance cams that I have fitted that would give a theroretical top speed of 96 MPH.

My concern here is that if I increase the teeth on the gearbox sprocket by too many teeth I will end up making acceleration sluggish.

[Leon Novello]

If the engine can`t reach peak revs on a flat road in top gear, it is over-geared--- an easy test.

[stinkwheel]

Do we want to be 'on cam' at motorway cruising speed? or effectively idling along and requiring a downshift to make an overtake?

I sit in 6th gear at 70mph on the wifes CBR600 and it'll do more than double that speed. Wouldn't pull the skin of a rice pudding if I cracked the throttle though, you'd need to drop at least 2 gears to get a hussle on. It'll do 70 in second and will be near peak revs but I wouldn't fancy sitting on the motorway in second.

I think at 21t mine is SLIGHTLY overgeared, I'd have to change down to maintain 70-75 up any significant hills but equally, it will do that speed in 3rd (and then is on-cam and revving freely). Difficult to tell exactly though because the clutch slips a bit over 70-ish and it's a pretty full-on sensory experience so a little tricky to tell when it is and isn't slipping slightly. Need to have a word with Mr Newby about that before the spring.