Yeo gotta run race gas :)

[shudup]

Well I got my 200X all done and was riding today and am getting pinging from motor...
my motor had a 12-1 piston in it when I got it.
id rather of had the 10 - 1 pistion but I guess ill go spend $3.50/ gallan for 104
only thing else im going to change is to a 11 tooth front sprocket, seems too high geared with stock gearing and 22 inch tires

I do have one question for anyone with the super trap 4" exhaust
how many disks you running mine has 12 and seems like a bit too much

I guess this will be lessons learned for building my spare motor
here is a couple pictures before I got it muddy

[shudup]

just checked the part number for the piston to be sure

its 12:1 with 1.00 overbore

should be pretty heathy when I get better gas and can tune it

[twgranger]

I run sunoco 110 race gas that is $5 a gallon, can't run anything lower.

[shudup]

im hoping I can get away with 104

[OldSchoolin86]

With the extra heat from the high compression you should make sure your plug is one colder then stock. That will help too.

[vartiak15]

my motor doesnt ping and im running 87 gas in it. it has the 12.1 piston in it too and it runs great. will i notice a power diff. if i run 110 gas?

[83185s]

u will definetly notice a difference in power ..it will start really alot easier and itll have more umph to it when u give it hell...i just put the 12:1 2mm overbore in my 185..its the 200x's max bore that i put in..i think its something like 67mm...pretty beasty i hope..havnt got it to get a spark yet

[J.D.]

u will definetly notice a difference in power ..it will start really alot easier and itll have more umph to it when u give it hell...i just put the 12:1 2mm overbore in my 185..its the 200x's max bore that i put in..i think its something like 67mm...pretty beasty i hope..havnt got it to get a spark yet

Now where in hell did you get this information? Going with a higher octane doesn't automatically give you more power. You should ALWAYS run the LOWEST octane possible without pinging. Lower octane burns faster. The only time you run a higher octane, is if you're pinging. Theoretically, higher octane will actually make it harder to start, because higher octane burns slower to prevent detonation. If you put too high an octane in something it doesn't require, it will actually hamper performance and cause it to lose power.

[KASEY]

YEP,,,, OCTANE IS CONTROL NOT POWER,,,, your not going to have any more power ,,, you won't get anymore speed,,,, its all in your head,,,,not your trike, you have to tune for more power ,,, with compression and timing,,, the more compressoin and timing advance you can run the more power you will get,,, and with that you will have to run higher octane to eleminate preignition which is what melts pistons,,,,,

[Huffa]

Both those guys are right. It's a big miss conception that higer octane will automaticly make your bike run better. Most of the times your just throwing away your hard earned money!

[OldSchoolin86]

If he's got a 12:1 and doesn't need higher octain in an air cooled machine then he most likely isn't getting full compression out of it.

[HaggLE]

Higher octane in a fuel injected car is a different story. Sometimes the computer in the car will de tune your engine to allow for the "bad" fuel. With bikes its all manual. You have to tune for the higher octane fuel. (compression, ignition timing etc)

[hrc85250r]

what do you guys recommend for maximum psi in a 250r before you need to run race gas...i am runnning about 200 psi right now in my 250r, but i dont hear any detonation or anything...but i do notice that when i come out of a turn and im really cranking on it i can hear a small "knock........knock..knock...............knock ..." really randomly and it will go away once my powerband starts to dissipate.....it isnt very loud knocking, just very slight and you wouldnt notice it unless it was yours.....

[J.D.]

You don't base it off PSI, you base it off - is the engine pinging? Try 87 octane. If it pings, moved up to mid grade, if it still pings, go to premium, if pinging persists move up to 100 octane etc etc until pinging stops. You want to run the lowest amount of octane possible.

[TimSr]

If he's got a 12:1 and doesn't need higher octain in an air cooled machine then he most likely isn't getting full compression out of it.

I was thinking the same thing, Im no thumper guru, but it seems to me that if you are getting away 87 octane in a 12:1, youre losing some of your compression.