1. 2 Stroke Husqvarna Motorcycles Made In Italy - About 1989 to 2014
    WR = 2st Enduro & CR = 2st Cross

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

Discussion in '2 Stroke' started by Brian Scott, May 19, 2017.

  1. Brian Scott Husqvarna
    AA Class

    Location:
    Bainbridge Island, Washington State
    Husqvarna Motorcycle:
    '11 WR 300
    Other Motorcycles:
    '01 CR 500R
    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!
  2. NCSteve Husqvarna
    Pro Class

    Location:
    Appalachia
    Husqvarna Motorcycle:
    12 WR300 13 WR165
    Other Motorcycles:
    02 XR250R 00 XR100R
    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.
  3. PaulD Husqvarna
    AA Class

    Location:
    Little Egg Harbor N.J.
    Husqvarna Motorcycle:
    2010 wr250( sold)
    Other Motorcycles:
    Triumph Sprint RS. Honda TRX300EX Be
    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.
  4. NCSteve Husqvarna
    Pro Class

    Location:
    Appalachia
    Husqvarna Motorcycle:
    12 WR300 13 WR165
    Other Motorcycles:
    02 XR250R 00 XR100R
    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 :thumbsup:

    Back in errrr...89&90 :eek: 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 :confused:
  5. PaulD Husqvarna
    AA Class

    Location:
    Little Egg Harbor N.J.
    Husqvarna Motorcycle:
    2010 wr250( sold)
    Other Motorcycles:
    Triumph Sprint RS. Honda TRX300EX Be
    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
    NCSteve likes this.
  6. PawPaw Husqvarna
    AA Class

    Husqvarna Motorcycle:
    2013 TC 449
    Other Motorcycles:
    Honda Crf450R + old CB750
    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
  7. Huskynoobee CH Sponsor ZipTy Racing

    Location:
    Castaic, CA
    Husqvarna Motorcycle:
    2011 TE449 2006 WR250
    Other Motorcycles:
    HDUltra Classic IT200 YZ250 SV650s
    I run AV 100LL regularly in my 250. I've tried it mixed with 110 Sonoco, and pump 91 with corn squeezins. I've had decent results with both, but I can certainly lug it more with the race gas. It's no biggie to run AV gas in a 2T because oil is mixed in. However, running an additive on a4T with AV gas is a good idea as it's formulated to prevent carb freezing at altitude. The best explanation I ever got was that it is "drier".

    My 449 likes it mixed with pump gas, Stabil marine, and a dash of premix. The best part? It smells great!
    NCSteve and 2premo like this.
  8. 2premo Husqvarna
    Pro Class

    Location:
    Northern NV
    Husqvarna Motorcycle:
    98 WR360, 1987 WR430, 1988 XC430
    Other Motorcycles:
    Sherco 300, 2002 KTM 380EXC


    mmmmm, love the smell, and just got back from Hangtown, they all run race fuel, the air smelled nice
  9. lankydoug Husqvarna
    Pro Class

    Location:
    MO
    Husqvarna Motorcycle:
    WR
    Other Motorcycles:
    TM 300en
    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
    NCSteve likes this.
  10. Brian Scott Husqvarna
    AA Class

    Location:
    Bainbridge Island, Washington State
    Husqvarna Motorcycle:
    '11 WR 300
    Other Motorcycles:
    '01 CR 500R
    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...
    Huskynoobee, lankydoug and NCSteve like this.
  11. Huskynoobee CH Sponsor ZipTy Racing

    Location:
    Castaic, CA
    Husqvarna Motorcycle:
    2011 TE449 2006 WR250
    Other Motorcycles:
    HDUltra Classic IT200 YZ250 SV650s
    Thanks for the reminder. It's time to hit up the local airport for some gas! :banana: