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 :eek:

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.

[J.D.]

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.


I would have to agree. While I know it's a completely different thing all together, my SBC 350 has 10.4:1 compression, I can get by with mid-grade but I still hear a light pinging, so I just run premium to make it happy. Oh well that's a completely different story....

[Wickedfinger]

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. Ditto Tim .... airleak on the jug somewhere maybe?. Technically, I wouldn't think you shouldn't even be able to start it on 87 octane.

[HaggLE]

If you retard the ignition timing you wont get as much pinging. The engine in question may have a retarded ignition. Try advancing it and you will get it.

[MTS]

my friend ran 87 octane with a 12:1 wiseco piston in his 200m that thing pinged and heated up so much that it siezed

[hrc85250r]

what does pinging sound like....i know detonation sounds kinda like a diesel under a hard load...but isnt pinging the same thing?

[Mr. Sandman]

Yep, everybody's right about not gaining power with higher octane. But, you will notice a HP gain due to the weight savings from your wallet. Plus your fuel supplier will love you, and in the long run you're helping the economy, so I say go for it!

[Mr. Sandman]

what does pinging sound like....i know detonation sounds kinda like a diesel under a hard load...but isnt pinging the same thing? You answered your own question as pinging is just the slang term for detonation.

[hrc85250r]

thanks sandman...just checking.....the knocking must be a cable or something slapping something else.....lol

[shudup]

most of the time you will here it when you get on the gas at a low rpm, mine also does it on higher rpm because of a combnation of the gas , higher compresion and mabe a bit of leanness on top end with stock jetting and aftermarket exhaust and air filter

[J.D.]

If you retard the ignition timing you wont get as much pinging. The engine in question may have a retarded ignition. Try advancing it and you will get it.


Were you talking to me??? The timing is not my issue, I'm running it at 10 degrees before TDC which in my experiences SBC's run best at 10-12.

[HaggLE]

What are SBC's? Ignition timing varies depending on the engine. Some cars run 4 degrees my dads race bike (XL185 motor) run 35 degrees. To me 10 seems a little to retarded. Run it on the "F" mark and see what its like. Does anyone know how many degrees that is?

[MTS]

SBC is small block chevy 350 v8....from what i hear you dont have many over there in aus...heh

[J.D.]

Are you serious??? WHATS A SBC??? What rock have you been hiding under for the last 50+ years???? Don't tell me you've never heard of a small block Chevy. I absolutely REFUSE to believe that.

[HaggLE]

I know what a small block chevy is i just didnt know what the acronym was.
No vehicles have been sold in aus with a chevy motor in it (maybe back in the 50's they did) so they arent that common. Mention clevos and windsors and im with ya. They have been in cars for quite some time here.

10 degrees for a little motor is not enough. Its a wonder it runs...

[AZ250R]

I ran 110 in mine one weekend, no noticable diff!?!? Well, it did SMELL PERTTY! :rolleyes:

[short4stuff]

yeah vartik .. I will say you have a compression problem too ... did you bore you cylinder before you installed the 12:1 ? .. atleast measure it and make sure there was only .002" of clearence? ... if you did, did you hone it? .. something doesnt seem right ..
Try going in about 3rd gear like 1/4 throttle.. and then shift to 5th .. and then try and accelerate... See if you hear a pinging now ..

I just installed a 10.25:1 and with 87 octane if i drop it down like that and try and accelerate it detenates ...... Sounds like teeth chattering .. not good knowing thats the piston bouncing off the cylinder :S :S :S :cry: