Forward Motion Porting

the porting does not need extra octane but if the head is modified for more compression it will need race fuel eric did a 99 kx144 kit for me set up for race fuel and the bike was way faster and easer to keep on the pipe it had so much low end that i went up a tooth on the front sproket because the bike would rev so fast you needed to shift a lot but after the sproket change the bike ripped, more power at every rpm and seemed to rev just as much if not more than stock and it was very easy to ride

In '98, I had EG port my RM125. According to Forward Motion's website, the "Mo' Better Everywhere" powerband is tailored towards 250s and 500s. That being said, when I send in my motor, I asked for something in between the "Mo' Better" and "More Mid-Top" type powerbands---as I wanted a strong 125, but didn't want to sacrifice the smooth delivery characteristic of the stock powerband.

My expectations were surpassed, both in terms of an increase in power and getting exactly the type of powerband delivery that I asked for---and that's coming from someone whose had motorwork done by some of the big West-Coast places. EG knows his ****e.

Anyway, with regards to your question about running race fuel. After Forward Motion ported my bike, at races I usually ran a 50/50 race/pump gas mix using Maxima Castor 927 at 40:1 and never had a problem. Additionally, when I practiced during the week, I typically used pump gas and never experienced any problems with detonation, etc. either. Moreover, depending on the track I was racing at, I switched between an FMF, Pro-Circuit, and Stock pipe and each complemented the porting just fine in my opinion. My point is, Foward Motion can tweak your engine to run on pump gas if that's your preference, just make sure to clarify that point when you send your motor in for work. Good luck.

Thanks for the favorable comments guys!

I think that the YZ125 has an excellent powerband in stock form. Porting can shift the powerband in either direction on the rpm spectrum with a loss on the opposite side. Its only with a big bore that you can really get a true wide and linear powerband.

Good luck, Eric