Which Piston And Compression Ratio Is Best For Desert Racing

[dezert_loko]

Hey Fella My 04 Trx Is Just About Due For A New Piston. I Am Currently Running A Je 12:1. It Did Perfect For Me For A Whole Year Of Torture. But This Past Weekend I Found Out It Was Ready For A New One.

Thanx For The Help.

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[Young&Fast]

Your best off with a 30:1 or 35:1 compression ration.

[rob-u]

Hey Fella My 04 Trx Is Just About Due For A New Piston. I Am Currently Running A Je 12:1. It Did Perfect For Me For A Whole Year Of Torture. But This Past Weekend I Found Out It Was Ready For A New One.

Thanx For The Help.

I would stick with a stock piston cause honda piston are pretty durable. I dont know what your other mods are but if you want more power look into an FCR carb and add a cam maybe even port/polish your head. The problem I see with high compression pistons is the loss of reliability as oposed to stock piston/compression and the fact that you have to use higher octane fuel which can be costly specially long distance desert races.

Your best off with a 30:1 or 35:1 compression ration.

That seems extremly high to me.

[dezert_loko]

i have a hatcams stage 2 cam, stainless steel valves hotrods crank hmf full exhaust and the tired 12:1 je piston. barrnet racing clutch

[CraigChr]

Stick with that 12:1...

[rob-u]

I dont know what the 450r stock compression ratio is but 12.1 doesn't seem to high. I guess if it's been working for you than stick with it. Maybe add an FCR carb, i've raced on 450r's with stock carb and with FCR's, the FCR's are much better than stock 04-05 carbs.

[creynolds]

Your best off with a 30:1 or 35:1 compression ration.

Awesome, just run down to your local station for some 192 octane!! Your comment was obviously being sarcastic.......hopefully!

[creynolds]

I'd also stick with 12:1. Proper jetting will make a huge difference in performance, life span and reliability. I don't mean simply using the right main jet. If you have anyone in your area that has a dyno and is extremely good with jetting it would be worthwhile to take it to them. If you find that they're jetting strictly by using an Air/Fuel sniffer then they are NOT the right people. On higher compression engines with with pipes, cams and other mods the sniffers are very unreliable. The carb really needs to be set up using overlying graphs of roll on, all gear, and coast down.

[D Bergstrom]

I dont know what the 450r stock compression ratio is but 12.1 doesn't seem to high.

The 04-05 TRX's only had 10.5:1 compression pistons stock, so 12:1 is a decent boost. From what I have read, just about anything over 12.5:1 is getting into race fuel territory on the TRX's. Before I went to the big bore kit on my BITD quad, I was running 11.5:1 Wiseco's for a year and a half. Never had problems and ran good compared to stock.

I would stay with the 12:1 piston. At that compression, you should have no problems running premium pump fuel. My worry with a "race fuel only" motor was that I would have to borrow fuel from someone at a pit and I would not know what type of fuel I would really get. I would hate to only get premium fuel if I needed race fuel.

Doug

[dezert_loko]

What do you guys think of the 13:1 is that pushing it a little. I just dont want to blow the bike up in th middle of an important race.