Sprockets

[ThorR88]

I have a 400ex with 8inch hipers in rear and 18inch TT and in front i have 10inch hipers with 19inch MX holeshots in front i have nothing done to the motor and i have the stock sprockets on im wondering what sizes should i run for mx tracks? also my TT are pretty much brand new do you guys suggest grooving them or no?

[underpowered]

gearing has to be played with. each track is different, so the setup from track to track will vary. for my local track, on a slightly built motor, i run stock gearing. but on a stock motor, you would have to go down to be able to clear a few of the jumps. mine barely pulls stock gearing enough to clear one of them.

as for groving the TT's, i have never ran them but heard that grooved is the only way to go.