piston question

[mad4106]

I have a 2007 450r and want to up the compression whats the highest can i go and still run pump gas and will a stage 3 hotcam work good on a stock bore with a hrc kit and higher compression kit?

[CJM]

12.5:1.

[mad4106]

Can u run a mix of 93 and vp 110 on a 13:1 piston?

[CJM]

13:1 is seriously not gonna make a huge difference vs 12.5:1.

But yes you should be able to mix it and be fine.

[mad4106]

will it make a big difference over the stock 12:1 piston or shoud i go a lil higher then 13:1 i still want it to be reliable though?

[CJM]

Whats going to make power is a port job, not going insane on the compression needing you to run 100+ octane always.

Porting is $ but will unlock ALOT of power, a good port job is at least 500 bucks.

[DnB_racing]

you can run 50/50 on 13:1 just make sure its as high as possible octane from a station that sells a lot of high test, and you don't really want a HC3, more of a big bore cam

ive ran high octane from stations before in a truck I used to own, and I swear some stations id be better off running the regular,

I rebuild my top ends just about every season but i run high compression , my current top has 14:1 with a thinner crf head gasket, and I can defiantly feel the difference in acceleration, but im not crazy about the present cam installed, its a Baldwin MX cam, and it just too smooth power delivery, I like a bigger hit of power, I will be installing a web

to be honest I could probably go more time then that on my top end ,
but I really don't mind playing around with different combinations of cams ports and compressions, the top end can be complete rebuilt in far less then an hour, and this is including dial testing leak down testing, along with shimming and compression,

do I recommend this for everyone NO but for those looking for some extra acceleration its there you just need to find the right combination and not mind tearing your top end apart until you do


a real good setup that's cheap and easy was a JE 13.5:1 piston, a HC11 cam and a cfr head gasket along with an open air box and a good flowing exhaust, and you'd be surprised how quick this simple combination can be, with this setup I would run 5 gallons race to 2 gallons 93 and when removed there was little to no carbon or detonation or ring wear, im sure I could have gone to 2:1 on the gas mixture easily with no issues

[mad4106]

Dnb racing did u mean stage hotcam 1 and would this setup be good for my 2007 model also and how would reliability be with that high of compression? Ima port and polish the head also.

[CJM]

I think he meant stage 2.

As for how reliable: Plenty if you use 100 octane or at least mix with pump gas

You basically got 2 choices:

1. Keep it lower compression and use pump gas

2. Go high compression and use 100 octane gas/pump mix or straight 100 octane.

Now heres the real question:

Can you easily get 100 octane and do you mind paying 7 dollars or more a gallon for it?

[chronicsmoke]

Race gas smells good when you burn it :D

If you plan on trail riding at all the race gas gets expensive..

I'm going from a SB/SS 13:1 piston to a SB/+3 stroke with a 12:1 piston because race gas and the availability here was getting to be a pain

[CJM]

Originally posted by chronicsmoke
Race gas smells good when you burn it :D

If you plan on trail riding at all the race gas gets expensive..

I'm going from a SB/SS 13:1 piston to a SB/+3 stroke with a 12:1 piston because race gas and the availability here was getting to be a pain

My sentiments exactly. Around here I can get it at the local track, a few gas stations or buy avgas at the local airport. None of which is really worth it for me.

[punk rock kiel]

maybe i ran the gauntlet but i ran sunoco 93 octane with 13:1 with no problems. i tore the motor down for other reasons and the piston and head are clean.

[CJM]

Could just be lucky Kiel, my buddy has a done up 06 and tried 93 from both sunoco and wawa and no matter what it would ping. Switched to 100 no issues. Course we are literally at or below sea level.

[punk rock kiel]

you know where we ride cjm, so i got lucky but mine is an 05. i trust sunoco fuels and i was jetted just right with a wideband

[CJM]

Yea, might just be high enough in elevation to run it using pump. Your lucky kiel!