250-500cc How much race gas to eliminate minor knocking

I recently did a top end on my '11 wr300 and am now getting a slight bit of knocking somewhere between 1/4 to 1/2 throttle or so after its warmed up. Strange it didn't happened w/the previous Wossner piston. Replaced it w/a Vertex. Base gasket was and is 0.5mm. Race head for the last 4 years and 3 or 4 top ends. 195 psi. Ported by Millennium Technologies a year ago after they re-plated the jug. 38 mm Keihin AS II. Jetting is spot-on; 172 MJ, JD triple stripe red needle, 40 PJ, AS 1.5 or so. Sea level to 2,000 ft. Always non-ethanol 92 w/Amsoil Dominator. I bought 5 gal of Renegade 110+. So...I'm looking to add just enough race juice to the 92 pump gas to eliminate the knocking. Will getting the octane to 95 do the trick? 96? 97?

Thanks!

Only 1 way to find out for sure. I'm running Sunoco 110 at 2:3 with non-eth 90 and Dominator @ 50:1. The 165 loves it.

50/50 mix of 100ll avaition fuel and pump 93 seems to minimize the part throttle ping in my 250. No local race gas available near me but airport is right down the street.

I found Sunoco 110 at a local car racing shop, in bulk at a fair price. They have some VP in bulk and can get anything in 5gl cans. Sunoco is a couple dollars cheaper because VP doesn't recycle the barrels. Whereas Sunoco gives them credit for returning empty barrels

Back in errrr...89&90 I got a little support from the local Honda shop racing XRs. They supplied aviation fuel, which the hopped up XRs loved. They put some additive in it, but I can't remember what or why now.

I thought I read some info here somewhere not to burn 100ll in 2T

I tried it straight mixed 50:1 with Dominator. Bike seemed a little flat and starting was a bit harder. The mix seems to work well. Lots of guys in my srea run it straight in their 2 strokes and are happy. I didnt want to start messing with my lectron again it took me quite a while to get it set up properly

If you now have a knock that was not there before, then I would go back and check the squish as it must have gotten tighter. I would suggest fixing that first.

Paw Paw

mmmmm, love the smell, and just got back from Hangtown, they all run race fuel, the air smelled nice

The additive was probably toluene which would make AV100 pretty close to VP or Sunoco 110

AV100 if you rate it the same way as automotive race fuels is actually 96 octane which if it keeps the knock away is far better than pump but not as good as VP110 or Sunoco 110

Thanks for the discussion fellas. Good stuff. I mixed 4 gal of 92 e-free pump stuff w/1 gal of the Renegade Pro110+ (111 octane actually: R+M/2) for a sprint enduro yesterday. If my calcs are right, then that bumped the octane up to 95.8. It was a warm day and I detected no mid-throttle knocking. My 300 seemed a little more crisp as well. Man...sprint enduros are tough...