12:1 piston

[mad4106]

Hey guys i have an 11:1 wiseco piston i was looking to upgrade to a lighter piston such as je or cp but havent decided. But i kinda want the 12:1. I was wondering if i get the 12:1 piston can i still use 93 octane or will i have to run race fuel?! thanks

[honda400ex2003]

you will have to run at least a mix of race gas if not full 110. I would say that 100 would probably work but it is quite hard to find.

steve

[mad4106]

Thanks ima just stick with the 11:1! That sounds to much of an hassale lol

[honda400ex2003]

yup... it is. also need to do some hd studs and such to help with gaskets leaking. they seem to pull easy with high comp. 11 is even very close on the stock studs.

steve

[bkb88]

Would a 12.5:1 piston be fine with running straight E85? I have also been doing some research on what I want for my motor when I go to rebuild it and it sounds like 12.5:1 compression is worth it if you have access to high octane fuel. I have E85 readily available in my area so I'm hoping it would suffice :D

[flyboy1294]

Correct me if I'm wrong, but is it not dynamic compression that effects the necessary octane? Not static compression?

So with the right cam, you should be able to run 93 octane with a 12.5:1 piston. I'm using that high of compression, and a stage 3 Hotcam, and I haven't had any problems with pre-detonation. (Granted, I can't get the carb dialed in ATM. :mad:)

Maybe I'm misinformed, and need to go with higher octane. Who knows. :blah:

[CJM]

Paging wheelie...paging mr wheelie for E85 consult! :o

[smithersusmc]

I am running a JE 416 12.5:1 with a stage 2 hotcam. I have had this setup for 2 years on the stock head studs with no problems. I run 110 exclusively. I have zero carb adjustment issues and no overheating at all. I have an EHS airbox lid with UNI filter. The Snorkel hole on the airbox is plugged. I have a Yoshimura full exhaust. Here is my jetting.

42 pilot
stock needle
152 main jet
A/F 1 3/4 turns out.
No choke.

I hope this helps.

David

[sneaky11]

Do you have any issue for starting with no decompressor with the 12.5?

I'm in rebuilt and I got the 12.5:1 CP piston and just shave 13.3 oz on my flywheel today, and I just want to know if the Hotcam will be good to start it or maybe go with an High-lift cam with a decompressor. thx

[smithersusmc]

I have no starting problems at all. I love the stage 2 cam there are no install hassles.

David

[honda400ex2003]

Originally posted by CJM
Paging wheelie...paging mr wheelie for E85 consult! :o

:D :D :D ;) shhhhhh. we dont always wanna let all the secrets out now marc. lol steve

[CJM]

Originally posted by honda400ex2003
:D :D :D ;) shhhhhh. we dont always wanna let all the secrets out now marc. lol steve

rofl steve..

[sneaky11]

Originally posted by smithersusmc
I have no starting problems at all. I love the stage 2 cam there are no install hassles.

David

Are you using an heavy duty rod? Mine is almost brand new oem and i'm wondering if I might use a carillo one...

[smithersusmc]

I am using a stock bottom end and stock timing chain. I am in the process of building a spare motor with the CRF450R cam chain and a stock crank and rod.

[slightlybent47]

I run almost the exact set up as smithersusmc with the exception that I run a 450 carb and I use U4.4 witch is 105 octane and Sunoco 110 and have no issues with it at all. I just barley bump the starter and she fires right up. I’ve had this set up for 3 years now and she still runs great. She dose run on 93 but she runs hot and pings a bit so she gets the good stuff. You can get 100 octane at any local small airport.

[honda400ex2003]

i think she deserves the good stuff anyway. dont cheap out on your mistress! whats the fun in riding her hard if she is sad about it everytime. you wouldnt get a dozen dead roses for your gf would you? well maybe... cheap hookers are the bad ones from what ive heard. gotta pay to play no matter which way ya turn.

:eek2: ;)

hahahahaha

oh man... im full of it tonight. thanks for the "she" inspiration slightly. steve