12/36 gearing for a 300ex

[enduro400rider]

im rebuilding my 300ex and im looking at getting a new sprocket and chain kit, i was thinking about the 14/36 gearing, the bike will have 20s in the back, so i would have uped the front sprocket one tooth, but with the 36 rear i think thats lowering it 2 teeth. i wanted to gain some top end, i do some long straights like 3 to 4 miles so top end is needed, i dont think it would have trouble pulling it, its going to be running a full pipe, 297cc 12:1, web cam, 400ex carb, and i will most likely be getting some head work done. im pretty light too, im only about 140 so do you think that gearing would work out ok?

[rooster300ex]

It should pull it fine. With the mods & your weight no problem.

[Blue250X]

If you want to gain topend you might want to try a 15 tooth front sprocket, you will have to get rid of your case saver though. But your setup should pull it alright. I'm not sure if you are only riding wide open or trails though. You could do 14/36 and get a new CDI with a rev limit increase and that would help with top speed too.

[enduro400rider]

well alot of it is ridding on roads, from one set of trails to the other, incase anyone has questions about me ridding on roads, i live out in the country where it is not a problem. i was also considering the 15/36 combo, anyone have a general idea of my top speed with that? i dont need to do like 80 or anything but i would just like to hold 45-50 with out revving the balls off the bike.

[rooster300ex]

Originally posted by enduro400rider
well alot of it is ridding on roads, from one set of trails to the other, incase anyone has questions about me ridding on roads, i live out in the country where it is not a problem. i was also considering the 15/36 combo, anyone have a general idea of my top speed with that? i dont need to do like 80 or anything but i would just like to hold 45-50 with out revving the balls off the bike.

When I put a 15T front sprocket on mine without the case saver. It just won't work. Not enough room. Do you have to mod the case.

[Sjorge450R]

dont do that 15/36 thats over kill on a non over bore 300. Just stick with the 14/36, you will like that. Just get a CDI so you can run +1000 rpms

[bwamos]

Agree.. 14/36 will be plenty or top end.

Stock rev limit on 20's you'll be at 57 mph top speed.
+1000 rpm limit you'll be at 65 mph.