When was the P7 introduced and what is the difference in specs and performance , if any. if Rotax introduces new stuff every 6 months, it will be expensive to keep up

I would like to explain this to everyone who owns a Rotax engine. The markings you see on the side of the cylinder P0, P1 etc with the latest being P7 is actually a mould number. Every so often when the mould that is used to cast the cylinder gets a little worn out, it is replaced. The P7 mould is now the latest. Of course they dont have only one mould but a series. The P5 mould was used for quite awhile before being replaced by P6. The P6 was short lived as it was only after 6 months when it was replaced by P7. This new mould would be used until the end of the year.

As to whether there are any significant improvements to the different cylinders, I am unable to confirm this. I have asked Rotax but they said there SHOULD be no improvement at all. A new mould will produce the casting to a tighter tolerance. When a driver uses a new cylinder and finds that he has improved his time, he contributes this to the change when probably it may not be so. I think only a bench test can define if there are differences in different cylinders.

I am in the midst of installing a dyno and should be in operation before the end of the year. I have different programmes to run tests on the engines. I hope by that time i should be able to give you a more accurate picture on this.

Last word of advice, you dont need to keep up with the Jones and buy newer cylinders. Do it when the old one wears out. To get better power, check your engine after every race. Change the oil as often as you can. Dirty oil will wear out your gears and slows down the engine. Check seals for leakages. Change the piston ring for a tighter clearance. We sell rings only also.

Hope this help you to understand the codes.

James Leong
Rotax Distributor

I was going to say it probably has something to do with the manufacturing process more than the actual cylinder design and that any changes are probably really small.... thanks for the really informative reply James.

I'm told from Ryan Haryanto crew, after 2hrs of running-in for his P7, the thing goes like a rocket..

But I ask my karting minder about the old vs the new model, he reply me