Sprocket Size Change

[Savo]

Hello everyone,

here's another one running non standard gearing.

It seems, though, that I go against the tide...

I run a 15/50 and I like it (yes, perhaps a 14/48 would have been a better choice..). Now my SR42 800 runs some 4000rpm at 90kmph (5th gear).

I mainly drive in a big town (Milan, Italy) and the traffic can be something serious to deal with. I need my bike to be as reactive as possible.
Sometimes I have to use highways (up to 500km) but I'm not much into speed, so let's say I take them slow (average 120kmph).
Rarely I enjoy dirt roads (but I love it). I haven't tried this gearing on dirt roads or off roads yet, but I always thought that, on dirt, being able to go as fast as the original gear can run, isn't as useful as to get the power sooner. I'll find it out in May (I'm going to a wonderful run in Tuscany).
Whenever possibile I take rides on the Alps and I think my 15/50 works better than the original. Simply more fun.

In town, my driving style is tipically a bit aggressive, but what I need is power, not speed. I believe that the original response it's a little bit slow and, moreover, when I get it I realize I'm going too fast. I need to get the power the engine can give at given rpm (say around 5000rmp) but I don't need the speed it gets at the rpm I need. In any gear. That's the reason why I changed the standard rear sproket with a 50 teeth one.

So far, so fun.

[BigBob]

Hello Belgrade. Last time I was there Tito was still in charge, so it must have been a long time ago!
I think if you change to 16/44 you will lose too much flexibilty and you will also have to lose the chainguard that protects the engine casing which is not a good idea.
It is also not possible to get a 44 rear sprocket for the Big. You can get a 42,46,47,48,49 or 50 only.
You would also have to lose about 4 links of chain.
Maybe 15/42 is the best compromise

[Chris BIG]

Paja I ran her at 15 / 42 and yes the cruising speed on the highway becomes much easier without running revs too high, had to get used to different pull off and the way she handles in suburbs but I got used to it and as I use highways more it suited me, had to shorten the chain too, have now upped the back sprocket to 44 and it is still ok for cruising at higher speeds. Warning for the lower end sprocket is how does the gearbox handles this, my gearbox is still in the workshop as 2 of the gears are damaged but I am not sure which 2. Whether this had something to do with the sprocket gearing I am not sure, my size might also have contributed in adding some strain as I am not light weight....

Chris

[Yuza]

Hi all,

I have made just few kms on the big (it was having overfuelling issues as you can read elsewhere) but I find the standard gearing too long (I run 15/47) and I am thinking of either z50 rear or z14 front sprocket as I plan to do some dirt roads and possibly no highways at all

z50 at rear is used by Savo here and should be the best choice for me as well, but it means I need a new (longer) chain as well. So I am thinking of a z14 front and keep z47 at rear

Did anybody have experience with that? Isn't z14 at front too small and potentially force the chain to run over a too small diameter?

Thanks

[dave#22]

Hi, on one of my bikes I run a 14/42 (520) setup with no issues.
the others are...16/48 (520)....16/47 (525) and 16/45 B&C special (525).
Dave.

[Yuza]

Thanks I will go for the 14 at front then as a first trial

[Ponkia]

Hi there,
Just a quick question: does a 525 1994-1997 kit fit on a 1991 ?
Thank you

[BigBob]

Yep, it fits straight on no problem.

[Ponkia]

Thank you, very much appreciated !

[Yuza]

Hi all, 14/47 seems to me a good compromise, at least on road.
Maybe still a bit too long offroad but I didn’t try yet
One point about the mod: with 14 sprocket there is no way to fit the “damper” round seal as it is too large in diameter and chain links are push outwards
I will consider moving to 15/50 with the next chain/sprockets replacement