RXB250L 14 Tooth Front Sprocket

zero_dgz · 07-26-2022, 10:10 PM

More show and tell. Information for posterity and Waldos who may pass this way in the future, etc.

I found a front sprocket that fits the RXB250(L). This is probably not much of a stretch, as it seems to use the same Honda style six spline sprocket as various other CG and CB derived Chinese bikes. I bought this one, and it fit no problem. The offset on the back appears to be the same and everything.

https://imgur.com/agVgQbd

The stock front sprocket is a 13 tooth, and I bought a 14 which seems to be as big as you can fit without having to grind off the guard around it which I'm not going to do. (I think the rear is a 43 tooth if that helps anybody.)

This didn't impact the top speed of the bike at all, which is just about 72 MPH (indicated 75 on the dash). It did, however, move that top speed down roughly a thousand RPM to 7000 or so in 6th gear. Low end acceleration doesn't feel impacted much even though I know mathematically it should be; The engine seems to have more usable power output between 3-6000 RPM than at redline. I can also wind out each gear a little further which I find makes it a lot less annoying to ride. The ratios on the gearbox seem to be really close together and if everything remained equal this thing could probably have a four speed box in it with the top and bottom ratios being the same and it wouldn't suffer in the slightest. Third and fifth basically have no reason to exist.

I've done some other tinkering, too. More to follow eventually.

07-26-2022, 10:10 PM	#1
zero_dgz Join Date: Jan 2020 Posts: 257	RXB250L 14 Tooth Front Sprocket More show and tell. Information for posterity and Waldos who may pass this way in the future, etc. I found a front sprocket that fits the RXB250(L). This is probably not much of a stretch, as it seems to use the same Honda style six spline sprocket as various other CG and CB derived Chinese bikes. I bought this one, and it fit no problem. The offset on the back appears to be the same and everything. https://imgur.com/agVgQbd The stock front sprocket is a 13 tooth, and I bought a 14 which seems to be as big as you can fit without having to grind off the guard around it which I'm not going to do. (I think the rear is a 43 tooth if that helps anybody.) This didn't impact the top speed of the bike at all, which is just about 72 MPH (indicated 75 on the dash). It did, however, move that top speed down roughly a thousand RPM to 7000 or so in 6th gear. Low end acceleration doesn't feel impacted much even though I know mathematically it should be; The engine seems to have more usable power output between 3-6000 RPM than at redline. I can also wind out each gear a little further which I find makes it a lot less annoying to ride. The ratios on the gearbox seem to be really close together and if everything remained equal this thing could probably have a four speed box in it with the top and bottom ratios being the same and it wouldn't suffer in the slightest. Third and fifth basically have no reason to exist. I've done some other tinkering, too. More to follow eventually.
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