What size sprockets are you guys running on the 250 CF Moto engines? I ask because I am re-gearing and had already been running 25 inch tires; not satisfied with running it in lo all the time. I'm looking for acceleration and climbing - not top end, but I'd like to still be able to hit around 30-35 mph. Right now I can get somewhere in the low 40's and I'd gladly trade that off.

I just changed the sprocket on my Blade XTX from stock (I think a 36t) to a 45 tooth. Was "real easy": took me only 3 hours last night and I've got another hour or so to go today... Suffice it to say, the bore for the Blade XTX driven sprocket is 58mm, not 57mm like I thought so I turned the axle down to handle 57mm bores. Also, pulling the sprocket was a little tougher than I figured because the right spline was frozen on from some light rust. After the obligatory maintenance and some oil seasoning of these parts, I'd figure the job should actually take more like a couple of hours.

Tip on the Blades: the pillow blocks on the center, driven shaft are grease packed and sealed by a little o-ring inboard and a nice seal on the outboard side. The o-ring is dainty-mine was destroyed at the factory during assembly (crushed/pinched), but the grease in the pillow bearing blocks was good. Replace it with a high temp/high performance grease and clean and season your spline shafts if you want it to be easier to take the CV joints/sprocket off in the future. You will need a bearing puller and snap ring pliers to change the sprocket. The main bearings, by the way looked to be a pretty good quality, heavy, tight and accurate. PIllow blocks are accurate as well.

43t on '08 and newer Joyner 250's
54t on Carter 250's and 300's
50-something on Kinroad 300's

Wow - so the 50 tooth sprocket I picked up is more "normal" than not, huh?

Going off this extrapolation, then if you put a motorcycle or similar engine in, you'd really need around a 60 tooth+ sprocket.

Kinroad 300 sprockets are 13 & 44

Someone is giving me bad information. I thought the Kinroad runs a 50+ tooth sprocket? I'm going to have to get with my source...

After a SOLID weekend of running the Blade on a 45 tooth sprocket, it felt really good and absolutely no loss of top end power for me, which was strange-in fact I felt I gained some. This may be because I unloaded the engine some and that the belt I was using was actually 25 mm instead of 24.2? Although, I'd rather doubt 1 mm on the belt would matter much.

Had speeds around 30-35 in lo and did not top out high. It was too fast for the trails and hard pack I was on - not enough straight away. The accelleration was very good and high was very useful.

Exploded a belt, however - was topping out low and after a few drifts, the belt blew up and the exhaust was red-hot... OOPs! Guess I better re-jet, though the engine fluid didn't overheat and it's running good. Just really ran the snot out of it.

Next is a 50 tooth; I think that's where I need to be and should gear it better for the 25 inch wheels. Maybe I won't destroy a belt in one weekend also.