High compression pistons????

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lolaaaa

New member
I'm going to do some work on my 07 rg this winter, i'm looking for some high compression 103 pistons, something around 9.8 to 1, i would prefer not having to use compression release valves, also my bike has 55k on it and i am not ready to rebuild the entire motor yet so i don't want to put to much stress on the bottom end. Any suggestions or recommondations would be appreciated. Thanks
 
Tell us what cam you are gonna run? The cam will bleed off some compression. You need to know your cranking pressure to determine if you need compression releases or a high torque starter.
 
cams are the key issue run the wrong ones and you'll need a better starter or compression release. Due to an unfortunate incident with a leaf spring recently(put a hole in my cases) I'm currently having my 10 SG motor rebuilt into a 103 now. My engine guy has talked me out of changing the cams(due to the starting/compression release issues among other things) and promises I'll be more than happy with the 103 and a good tune. Doing the lower end upgrade, crank welded/flywheels trued w/timken bearings while it's torn apart along with torrington cam bearings. Want this bike to be reliable more than anything as it's my touring bike not a street racer/bar hopper.
 
I read where you posted this in another thread. Please tell us what the other things are besides starting/compression release. If built correctly, starting/compression releases are not an issue on a reliable, mild motor.

Here's the way I see it although, its just my opinion fwiw.
Decide your riding style.
Pick the cam that best suits your riding style.
Build your motor around that.

And flhxkiller, maybe for your riding style, the stock cam is best. It is certainly an EPA compromise, but it could be the right cam for you.
 
I can highly suggest using the s&s 106 cylinders and pistons for your upgrade. Just add the flavor of the month cam that doesnt build too much cylinder pressure and you will be happy. I am running the tman 555 cam.
 
S/E flattop pistons & 103 kit will get you where you think you wanna be (9.8 ~ 10:1 static CR).

I can ASSure you, you do NOT want high compression pistons in that setup, with SE255 cams. Hot only with the cylinder pressure be "through the roof", you will have exceeded the CR best suited for that cam.

As SPOracer noted, there are many superior alternatives. He has one of them on his scoot.
 
255s are not the right cams for high compression, sporacer and PhilM said it well above.

Read FuelMotos thread on the T6-6 and TW-555

I've never run a Tman cam, but I like TR.
And may be looking at one for my next build.
 
was considering running the SE255 cam originally, the other issue is that I ride in areas of the country that have shitty gas(ie low octane/ethanol blend) on a regular basis and that the torque type of cam doesn't care for that type of fuel. I'm looking for a good running bike that will run on any type of fuel in a pinch w/reliablity being first and foremost on this bike.
 
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