Sprocket / counter sprocket opinions

[Charles Gresham]

What sprocket / counter setup do you like for a 250 HS? I am going with the 520 chain conversion, and my worn out set up is 52 tooth / 13 tooth. Basically I want something that will do well in hare scrambles and VMX. I am thinking 54/12... pro's / cons?

1974 Penton 250 Hare Scrambler
1973 Honda CL 100
1983 Honda XL 185
1993 Yamaha RT 180

[joe novak]

Hello,  Presently, your sprocket ratio is 52/13 = 4.0 (52 divided by 13 equals 4.0)   Your new ratio would be 54/12 = 4.5.  The 4.5 will give you gears closer together, and a lower top speed.  What I try to select is a rear sprocket which will give me the gear ratio which will work for me using the front sprocket which I have chosen.  I do not like to "wrap" the chain around too small of a front sprocket for several reasons.  If you select the front sprocket and the rear sprocket which will work for H.S. (hare scrambles), you may be able to easily switch the front sprocket to one fewer tooth which will give you a good ratio for M.X.   You can usually do this by only adjusting the chain, rather than adding or removing links.  Are your H.S.'s tight, woods, wide open trails, or other?   Are the M.X. tight, wide open, or other?   Fewer links and smaller diameter rear sprockets are less weight.  Too small of a front sprocket tends to drag on the swing arm.  Drag is not good.

[brian kirby]

Honestly, gearing on the KTM engines with 6 speed transmissions is not a huge issue. Even on the 5 speed 400 I almost never use 1st or 5th. In vintage hare scrambles you will rarely (if ever) need 1st, and you will never use 6th, and probably not 5th either. In MX you will pretty much use 2nd, 3rd and 4th too. I agree with Joe about not using too small a front sprocket, it increases chain wear. I would go back with whatever 520 combo gives you the same final ratio you have now.

Brian

'72 Berkshire

[Charles Gresham]

The predominant application is for tight to average width woods trails.

1974 Penton 250 Hare Scrambler
1973 Honda CL 100
1983 Honda XL 185
1993 Yamaha RT 180

[tomale]

Hmmm, Believe it or not, I had the same problem a few years ago and when I went to a Mikuni I had to change the gearing as well, I had to go taller.. and the faster I got caused me to go a bit taller too... so if you find yourself shifting alot then you may be a candidate for a bit taller gearing...

Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)74'
250 hare scrambler (project bike)