Detuning for non-race gas?

[NM_KDX200]

I'm looking at an '05 KX250 but my understanding is that a lot of the modern MX250's (and the '05 KX, particularly) really, really need race gas. I just absolutely can't do race gas because I live in a really remote part of NM. Best I can do is premium unleaded at 90 octane or so. And plus, I just don't want to buy race gas!

Why does the bike need race gas? Is it because of high compression? What could be done to de-tune it a little so that it would run on premium? Being that I'm going to use it as a woods bike and not a full-tilt MX'er, I don't mind losing a little engine performance.

 

[bclapham]

yep, it has a lot of compression.

a good fix is to have the head machined by a tuner- if i remember rightly from Eric, i think it has a 14mm wide squish band. narrow it to 10 mm with a 25 degree blend into the bowl.

 

[Buckholz]

You live at higher elevation. You will not need race gas. Run it a little rich, this will help it be less detonation prone. Run fresh oil/gas mix, octane rating is said to decreas with .

Me and most of the buddies race A or AA, running modern two stroke mx bikes in enduro and HS's and rarely if ever run race gas.

 

[99raptor]

Watch your spark plug .If your not sure what your lookin at have someone who knows read it.

 

[2-Strokes 4-ever]

Or.......a cheap fix is adding one more base gasket (to lower compression) however, this will slightly change port timing and make the bike run a little more "top end-ish."

 

[bclapham]

Or.......a cheap fix is adding one more base gasket (to lower compression) however, this will slightly change port timing and make the bike run a little more "top end-ish."

that doenst work. ;)

 

[chrismxer]

Alway's run fresh gas and oil mix. Try different gas stations, I have the best luck with shell in my area (bay area), and if that doesn't work just run a gallon of race gas to 3 gallons of pump or add some of that octane booster from maxima or another reputable brand.

 

[Vic]

I'd start by retarding the ignition timing.