What can I do next...(more power)

I have a 2008 crf50 with the following mods

FMF pipe

uni air filter

bbr cam


advanced timing

I would like more power, however I would like to keep the 49cc displacement.

(I want my fiddy to be a fiddy, not an 88)

I have looked through the free mods and have done pretty much everything but the head gasket mod and the choke mod. (my bike wont start without the choke)

I dont want to change the gearing. (I dont have enough torque or top speed)

Money to spent is $500 or less.


With $500 you could buy a very nice bore kit. But if you're set to stay 50cc, high compression piston, ported head, camshaft, lighten crank flywheel, titanium clutch weights, maybe a carb from a 70cc bike to go with the exhaust.

I have already put in a bbr cam (I believe white brothers actually makes it for bbr)

I really want to keep my engine size as a 49cc. I know the old saying, "there is no replacement for displacement" but I really dont want to go the route of bigbore.

when i did a search for the high compression piston, one member said that it lost power on the dyno. and a few others said it had no gains.


I will start looking for a xr/crf70 carb

has anyone tried a stroker kit for the 49cc engine?

are there any drawbacks from a lightened flywheel?

High Compression piston will raise compression and with proper tuning will definitely raise power. Powroll makes 11:1, 13:1, and 15:1 pistons for the CRF50. Stroker kit will be more displacement and will not be 49cc and you will be breaking your rule. Not to mention that a bore kit is easier and probably performs better. A stroker crank only brings you to about 60cc anyway. A lightened flywheel has no drawbacks as far as I know. If you went as far as an inner rotor you may have problems snapping cranks or exploding clutch baskets. But you will be safe with a lightened flywheel.

great info... how high of compression can I go before I have to run race gas? I would like to stick with the stuff from the pump.

11:1 would likely go fine on pump. 13:1... maybe. I wouldn't use 15:1 with pump gas though.

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