chain choices.

lorha4959

New member
hey all. finally getting more serious about my getting my uas setup going. going to be running a taft 250. do i need to set this up on 520 like the 450mx engines? i had a lot of saves threads from here on the subject but lost all my bookmarks.
 
35 will do you just fine on your jackshaft. You can run 428/520 but the final ratios start getting weird and few/far between when you’re running a two cycle with those big teeth. The teeth changes are pretty significant and you’re basically married to your primary belt ratio. Keep up on maintenance, change out worn gears, run the ring gear style basket and keep the chain straight. You’ll be good.
 
You can run 428 but you can also run 420 which is the same size as #40 but a motorcycle grade. There plenty of gear choices to run for ever what you need. I personally as a big guy and dont run the risk of a little #35 chain breaking and wrapping around my arm. I've broken them with a 135cc.
 

nobozos

Member
Al if he is running a 250 he will probably be in the 1.79 to 2 on the primary side jack shaft and final gear anywhere from 4.10 to 4.6 at least here in the south east. later Chuck.
 

alvin l nunley

Premium User
Al if he is running a 250 he will probably be in the 1.79 to 2 on the primary side jack shaft and final gear anywhere from 4.10 to 4.6 at least here in the south east. later Chuck.
I'm not really sure what you're saying here. I'm saying that a ratio is a ratio regardless of the chain pitch.
 

T-STEAK33

Member
I run 428 chain on my 450 and 428 sprockets from CMS sprockets but i do know guys running 35 chain on jawas and 250's and get away with it.
 

lorha4959

New member
thank for all replies. i think itll be 420 or 428. even if it will hold, 35 just looks small lol.

whats happened to seays and cms website. ive found cms' square store from facebook. is that all they have?
 
+ 2 on what Brian said. I don’t like running a 35 chain more than 2 times on an open reed motor but I’ve ran the living bejesus out of 428 and never even changed out a countershaft sprocket, rear gear or chain.
 
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