Changing gearbox ratios on my M659 engine on first, second and sixth - how, why, etc
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- Опубліковано 10 вер 2024
- For the M659 engine I've had some gears made to replace first, second and sixth to change the ratios and gaps between ratios. Not sure if it will work - only 1 gear on each pair has been changed so the replacements are trying to add or subtract a tooth from a designed pair so it might be noisy or who knows what else. It's a situation heavy on mathematical constraints. But, we'll see what happens in the fullness of time. Only way to find out is try.
I'm doing this to make the gear ratio set more even - lower first, reduce the gap between first and second and raise sixth. Close ratio gearboxes annoy me somewhat when used on models that are not specific use. Peaky track bike maybe, but a Monster is a pretty wide ranging piece of kit all round, so low speed commuting is as important as inevitable freeway boredom.
And, my old 400SS had one of the widest ratio 6 speed boxes Ducati ever made. Almost comically so. Having experienced that, and everything else in the range, I must say I like them wide.
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A really interesting exercise. Looking forward to hearing how it feels on the road. On the 1100, the problem is it's overgeared in top meaning you couldn't happily engage sixth at anything below 110 kph. Also, town speed (50 kph) was hard to maintain as second was a bit low and third was too high. I went down the sprocket change route going from the standard 15/39 to 15/42 (via 14/39). The option of swapping individual ratios to fine tune the gearbox is very appealing (if considerably more expensive!)
i like 15/43 in wide ratio 1.84 primary drive models. but a 14 front is a good step if you're not replacing the lot. this is a very expensive way to change the gearing.
@@bradthebikeboy Agreed. 14 tooth front is quick, easy and cheap. The 15/42 seems the best of the options I've tried so far, kinder to the chain and sprockets I believe, but heavier with the longer chain and definitely more expensive!
@@luddite6239shouldn't be any more expensive. i use esjot rear sprockets on them, much cheaper than oem. i doubt the weight will make much difference. and while the larger front is technically better, the typical owner neglect will have far more influence on life or lack of.
@@bradthebikeboy Agreed (again!) When I fitted the 14, I read many comments from online "experts" saying that "...the chain run's too tight" or "... there's not enough clearance round the swinging arm". But after 12,000 miles, the front sprocket showed no appreciable wear and there were no noticeable witness marks on the plastic swinging arm protector to suggest the chain was running too close. I only changed because I wanted to try one of the after market rear sprockets, which mount on a separate carrier.
Awesome info, be keen to hear an update after you're running it. It's not much different to gear ratios in other Ducatis, so it should be ok.
the concern is not the ratios, but the gears physically.
Ah, I see. Like the different diameters would cause the gears to mesh differently?@@bradthebikeboy
@@adamroper1197 the diameter has to be the same, so the tooth shape is manipulated to make it hopefully work.
You said the 6th gear ratio was 26/24 now it’s 27/24…. How can you not change the opposing gear( the 24 tooth) to 23 tooth coz if you go up 1 tooth on the input gear, you must go down 1 tooth on the opposing output gear…. To allow them to mesh.
If I’m wrong, please explain why, thanks.
the gear man puts it into the computer program and it puts out a profile shape that should (hopefully) work with the original other gear. here's hoping.
I'm interesting, what final drive pair did you use on your 400ss? I have a Monster 400cc, with 15/48, and thinking about change to 15/45, but I don’t know if this will be ok for the 400cc engine...
my 6 speed 400ss i ran 14/39 i think. it was meant to be 14/45 by the manual, i forget what was on it when i got it. is your monster 5 or 6 speed? carb or injected? none of which are anything like the 400ss gearing wise.
@@bradthebikeboy My M400 6 speed and injected
@@user-uc4hw4cl3x that's the same as the 800 and the later m696, etc. i usually run 15/48 on m696 instead of the std 15/45 to make them nice, so that should be fine. if you try 15/45 and you don't like it, replace the front with a 14 and that's much the same as 15/48.