Jawa Babetta 207 X25 vs X30

So I have a Jawa X25 but I would like it to be as fast as an X30. So other than the 13t sprocket, does anyone else know what makes it faster than the x25? (edited)

Re: Jawa Babetta 207 X25 vs X30

I haven't been able to find a detailed list of differences, but I expect the usual things apply. Carb / intake diameter, exhaust, etc.

It's worth noting that the Jawa promotional material does say that the 30 mph versions have higher compression, so they probably ran a thinner or no head gasket:


Unfortunately the 207 spare parts catalog doesn't detail which parts go to which speed versions, but the owner's manual does say that the higher speed version takes a larger main jet in the carb, which implies various changes for better airflow through the system.

Also, you can put a 210 cylinder on a 207; it has much better porting and they are still available (treatland or jawashop). (edited)

Re: Jawa Babetta 207 X25 vs X30

Yeah, I also can barely find anything which is why I'm asking. So far I know that they changed the amount of teeth on the sprocket to more for the faster versions. I also know that from the x20 to the x25 they upjet it going from 58 to 63. I can only infer they may have upjetted from 63 to a little bigger for the x30 as well. On some spec sheets they kept the compression ratio rating the same on all models at 7.5 but I know on stuff like that it always varies.

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