After some research and just plain luck, I found a replacement for the 15 tooth front sprocket that came on my Tao Tao 250.

A JTF 259-14 will bolt right up as a direct replacement. JTF sprockets does not sell to the public but an online search for the sprocket model will reveal many sources.

This swap had the effect of dropping the transmission about one gear. I don't have to slip the clutch near as much to launch and rock crawling is a lot eaiser.

I don't know how much the top speed dropped as I am not interested in going over about 20mph.

Grampz

 

What did the machine have on it to begin with. I have two different front sprockets that I use depending on the track. On the Blaster I run the 13 tooth which is stock for short technical tracks and I got to a 14 for a track that has longer run ways, just a little more speed with the larger front.

 

These machines have a 15 tooth sprocket from the factory. They gear them for more speed but with the 4 speed transmission, the lower gears were too high to suit my riding style. I was always stalling it because I had to slip the clutch and rev it to launch from a standing start. With the smaller front gear, it is much more drivable and comfortable on the trails I ride.


Grampz

 

Grampz,
How many tooth is the rear sprocket on your Taotao 250D ? I have a 250D also and have the same problem it just doesn't have any low end power and stalls out in first. Mine has the 15 tooth front sprocket and 39 tooth rear sprocket. Did going to the 14 tooth sprocket on the front stop the stalling in first or just make it better ? Thinking of going with the 13 tooth front to match the 39 tooth rear sprocket..........thanks

 

Hi,
I think my rear sprocket is a 40 if I have counted correctly. By going to the 14 tooth front sprocket, it helped a lot with the stalling. I will still stall if I am starting up a hill with the wheels turned but normally it is a lot better. It seems to me that the front sprocket is a lot easier to change than the rear sprocket. I think you will have to disassemble the rear axle to change the rear sprocket. The front sprocket is a simple matter of removing the cover and taking the two bolts out of the clip. The cover will come off completely if you move the shift lever while manuvering the cover up and out.

The bike is a lot easier to launch from a standing start with the lower gearing. I rarely have to slip the clutch much to get going now.

Grampz

 

Thanks for the reply Grampz, maybe I mis-counted the rear but mine does have the 15 tooth front, and if the 14 tooth helped that much I think I will go with the 13 tooth for a little more low end since we live around some major hills. From my calculations the Taotao 250D gearing is off from the factory since you usually have 3 teeth on the rear sprocket for every 1 tooth on the front sprocket, so with a 15 tooth from the factory they should of installed a 45 tooth rear sprocket and not a 39 or 40 tooth.

So I assume the JTF259.14 you installed matched up to the factory 428 chain, but did you have to remove any links ? I will probably just order the JTF259.13 with the 13 tooth and try that, cause like you said the front sprocket is easy to get at and will be less expensive than a rear sprocket change.

I really appreciate the info Grampz as I am sure others have the same problem, but nobody seems to have tried fixing the gearing problem which seems to be a major flaw in the Taotao 250D design from the factory...................Thanks again, Slydog

 

Well i have a Jetmoto 250 late 07 model and i believe i have a 15 in the front from what i hear and a know for sure i have a 42 tooth in the back. Just havent had time to take apart the front cover cause its a bit hard to get to. But i also need more lower end torque for the riding i do and im thinking about swapping out to a 13 tooth in the front. But do you guys think i need to swap the 42 in the back if i go to 13 in the front? I also wonder if the same JTF-259-XX would be the same for my bike also where did you order them from? Thanks

 

Balanis03,
I don't know if it would fit the Jetmoto 250, it depends on what size chain it has and the shaft size for your motor. To figure out your chain size like 428, 520 etc. use the link below which has good info on chain sizing. Then measure your bolt holes in mm for your front sprocket along with the shaft size in mm and the width of the sprocket. I will post a link to the JTF259.xx for comparison to your measurements. As far as where to get them, just do a google search for JTF259.14 and go from there as JT sprockets does not sell directly to the public. Here are the links........................Slydog

http://www.gizmology.net/sprockets.htm

http://www.jtsprockets.com/fil...mages/large/jtf259.jpg

 

Slydog,
I did not have to remove a link from my chain to go from 15 to 14 tooth on the front sprocket, but I am almost out of adjustment on the chain adjusters. I believe you will have to shorten the chain if you want to go to a 13 tooth front sprocket.

I replaced the chain that came on my 250D with a 428 heavy duty chain and that stopped all the chain stretching problems I was having with the original chain.

I don't remember the vendor I purchased the sprocket from as there are lots of them on the internet. I never did dope out a replacement for the rear sprocket because the front sprocket worked out fine for me.
The JTF 259-xx sprocket is for a 428 series chain. It fits a bunch of small displacement street bikes such as the 79 - 80 CB 100.

Grampz

My riding videos:
http://www.youtube.com/lmcph126

 

Grampz,
Do you happen to remember what brand chain you used, as we are having the chain stretching issue with the stock chain. I have been looking at Renthal and KMC 428H heavy duty chains but just wanted to know what worked for you. Thanks again, Slydog