I’m moving this to the general forums since nobody replied on the 2-cycle page. How long is the piston life on the KA100s before replacing them? Now that some people have been racing them in the USA. Does the engine have a Rev limiter like the X30? Are the carbs fairly easy to tune? Are the starters reliable? What are your opinions about this engine? Do you think it will eventually replace the Yamaha KT100 or replace 125 TAG classes.</span>
That engine package is fairly new, and some clubs here in Cali are still testing it, and some have already raced them with very good results.
I hear nothing but good things about it, that the bottom end is a lot beefier with a 125 cc crank and bearings, that it is screaming fast and reliable, etc.
The only issue I’ve heard so far is that the onboard starter is having some issues, but they’re working on it, as they don’t want it to become an issue like we’ve had in the past with Rotax and Leopards.
Your question about piston life is a question you should ask a shop, seller, supporter or a team that supplies those engines, as far as I know they are still trying to make it grow, and I know of a guy that is willing to let racers borrow engines to test them and see how they like them.
And the answer to your other question about the future replacement of KT100 is correct, not only the KT100 but will also replace the KPV for sure.
I ran the whole USPKS season on one piston in KA. We took it apart a couple times to check it over and the piston still looked new.
There’s no rev-limiter, but the engine basically stops making any power once you reach the upper 15k range, so you gain nothing by spinning it hard.
Carbs are easy, same general idea as any other carb. Depending on the track, I tweaked it a little bit from time to time during the race, but nothing drastic. If you know how to tune a Yamaha or KPV carb, it’ll be easy. An 1/8 turn here or there to get the right EGT and you’re good to go.
Starter held up all season, minus when we forgot to charge the battery. More reliable than the X30/Leopard starters were. Seems to crank over much easier than those engines too, limiting how long you have to hold the starter button down.
This engine will probably replace Yamaha at a national level and complement it at a regional level. It’s definitely comparable to KPV in terms of speed. I don’t think it will replace TaG racing at a national level, but maybe at a regional level where the top level class needs to be something more cost effective at the detriment of outright speed.
I love the engine and will be running it again next year. At Dousman there has been a lot of interest and some shops have been giving free test drives on the last few club weekends this year. I have seen a lot of drivers pick up KAs for next year and they are putting laps on them at Dousman already.