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Re: M20 engine sprocket

Thanks baza,Sorry mixed up my ratios, thought 20 teeth was too low a gearing cant remember what It was like with a 20 tooth sprocket on as only took it out a couple of times cos the clutch was slipping too much,meybe that was part of the problem, Andrew.h.

email (option): warbikes@gmail.com

Re: M20 engine sprocket

Andrew. A standard WM20 engine sprocket is 19 teeth. 20 teeth will raise the gearing for a slightly higher cruising speed. They run out of steam on hills a bit so more gear changing if you go any higher. I have a 21 tooth sprocket on my M21 engine, which is fine for normal use. But I would prefer the bike to have a smaller sprocket and more 'buzzy' for convoy duty or Dartmoor lanes. Ron

email (option): ronpier@talk21.com

Re: M20 engine sprocket

With the weight and limited power output of the M20 you have to choose where in its range you want the performance and select the gearing accordingly...

If I used mine primarily in the hilly lanes of S.Devon where I live, I would go with the 'shorter' gearing for sure...It all depends on what you need from the bike...
Generally, I like the less revvy 'feel' of a bike with taller gearing so I gear all of mine as high as practically possible...

If you want better pull on the hills and better acceleration (relatively) go with a smaller sprocket (18/19t)..for better cruising speed go for a bigger one.(20/21t)..

However, if you make the gearing too 'tall' there isn't sufficient power to pull it and the bike will slow down as soon as you hit a gradient (or strong headwind)..You will then spend a lot more time in 2nd and 3rd gears and use more fuel as a consequence..

You could enlarge the engine to 600cc or more but it's not worth it unless you intend to ride it a fair bit, which makes the conversion cost worthwhile..
Also, you will then lose the experience of using the bike as it would have been when a DR rode it...something to consider perhaps..

Alternatively you could get a 16H..same weight and power output but it's cousin is a Manx Norton and that makes it twice as fast.. ...Ian

email (option): ian@wright52.plus.com

Re: M20 engine sprocket

Ian,thanks for your input, as the 20 tooth sprocket is already fitted, I will try that and see how it goes in Normandy this year if not I will fit the 18 tooth one and give that a go, Andrew.h.

email (option): warbikes@gmail.com

Re: M20 engine sprocket

For a dollars worth of Mig wire just weld up your heads if you want a cheap performance gain! Honestly you won't ruin anything and a dremel takes care of head shaping. I know I'm harping but it's so simple! ( I have had a scotch)!

Re: M20 engine sprocket

Your right Douglas...'Discreet' improvements can be made that are not expensive and will give more performance....I have gone with enlarging the engine and a moderate increase in compression ratio but this is relatively expensive to do...

It gives a good improvement in performance particularly in the mid range where it is most beneficial for climbing hills, with reasonable increase in the comfortable cruising speed...It certainly makes my bike far more practical for the longer runs I do periodically and there is the added benefit of an improvement in fuel consumption figures....

I fully accept the argument though, that by making too many changes you alter the fundamental character of the bike and don't get the true 'M20 experience'....

In my case I've had that experience on numerous occasions previously, so I'm fully aware of what I'm 'missing'.. ...Ian

email (option): ian@wright52.plus.com

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