Norton 500T gearing

It would be straightforward to set it up with standard ES2 / Model 18 gearing - 20T engine sprocket, not sure about the gearbox one.

Top gear in this type of countershaft box is always 1:1 so although the box will be wide-ratio, in top it makes no difference. The only way to overcome the rear sprocket size is to fit a larger engine sprocket.

You'll have to check the sprocket offset as there are at least three types but RGM lists up to a 23t engine sprocket for most of the singles.

Gearbox usually stays at 19t.

Do have a think though if you're going to gear for 85mph on trials universal tyres...they can move around quite a bit.

According to Bacon - if your bike is between '49 and '54 - your g/box sprocket should be 16 tooth whereas the standard 500 (eg ES2) has 19. The engine sprocket is 20 in both cases. It would seem that the g/box ratios (ie the cogs) were the same for both models. Hope this helps. George

Previously barry_williamson wrote:

All thanks for your assistance with this. I only want to ride at 50mph but do not want to bike to be under stress as at the moment, 1st tops out at about 5mph and top gear at 35mph so the engine is revving a lot at low road speeds, and I would love to ride the bike for longer then 3 miles on back roads.

Hi Barry, I had a 1952 500T from new, I found that normal riding going to work etc 45 mph was a happy cruising speed. when competing in trials I would be passed at times by the same modal thrashing along at close to 65mph, The 500T in later life was often geared down for vintage trials. The 19in rear wheel was exchanged for a 18in one to get better tyre choices. If the gearbox is stock there should be a large spread when changing into top gear I would check the engine sprocket and gear up 2 teeth if possible or on the gearbox drive which means more work. Bryon

Sorry to go off topic but this photo on a Ford lorry site amused me.

"No Dirt No Discomfort No 500T"

...or am I missing something ?

Hi Barry,

The Roy Bacon " Norton singles" book has lots of info on the 500T including gear ratios and sprockets. All you need to do is fit a 19T gearbox sprocket and 20T engine and you should have 60mph cruising and still be able to plonk at walking pace if you have the wide ratio 'box.

George, sorry to say all the gears are different to a road 'box. It was the WW2 Big 4 sidecar gearbox wide ratios originally and then tweaked.

Regards, Richard.

Barry,

Lucky you!! As the oldsaying goes "Better born lucky than rich"

Check your rear wheel sprocket as your granddad might have fitted a larger one, it should be 42teeth.

Richard.

Hello Barry, I use my 500T for sidecar trials and use a 18t engine sprocket. I sometimes take the chair off and fit a 23t engine sprocket for solo road use this gives me a comfortable 50-60mph cruising. I keep separate chains for solo and sidecar use with the sprockets. If you haven't already ordered sprockets think about only changing the engine sprocket as it is much less work and you can quickly change the gearing back when you eventually are tempted to try it off road! It takes me about 15 mins to alter the gearing on mine. Make sure that you specify the correct offset for your replacement sprocket(s): there are three types available. As you have found out the 500T does make a lovely road bike.

I wouldn't advise removing the ball from the engine breather non-return valve. Its purpose is to maintain a lower pressure in the crankcase by allowing pressure out but not allowing air in. If you are concerned you could check that it has been fitted the correct way round. It also prevents water etc. being drawn into the crankcase. Once you have given the bike a couple of decent runs the smoke may well reduce. Think positive: any oil in the exhaust will stop it rusting inside!

Rod