right cam for high compression?

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May 29, 2012 | 10:52 AM

#11

6 gun

Seasoned HDF Member

Joined: Mar 2008

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From: Central Texas

If you have an EFI I'd take a close look at the SE 259e cams

May 29, 2012 | 02:56 PM

#12

jlasoftail

Thread Starter

Road Warrior

Joined: Oct 2009

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From: P.E.I. Canada

Quote:

Originally Posted by djl

Kirby is right, as one would expect; something is wrong. Your CCR should be under 200psi with a standard BB kit and 255 cams. The gauge is reading wrong or, as Kirby suggests, heads were milled. You need to know what you are working with before you start making any changes. I would check compression again with a different gauge, probably more than one before I accepted 220psi as CCR. Too many guys are running that combination without issues.

The bike has been mine since new, so I'm pretty sure the heads haven't been touched... Oh, and we did two gauges, one was 220, the other read 215.

May 29, 2012 | 04:02 PM

#13

djl

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From: san antonio

Quote:

Originally Posted by jlasoftail

The bike has been mine since new, so I'm pretty sure the heads haven't been touched... Oh, and we did two gauges, one was 220, the other read 215.

The math just doesn't support 220psi. Maybe you have some smallish chambers? I don't know what is going on but I do know that a standard 103" BB (flat top piston/cylinder kit) with 255 cams and all else stock, won't push CCR to 220psi.

Was this a dealer build? Are you sure you didn't have the 10.5:1 high compression pistons installed?

May 30, 2012 | 06:27 AM

#14

2009blackpearle

Road Master

Joined: Dec 2008

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From: Niagara Falls Canada

stage 2

when i did the 103 stage 2 with 255 cam and flat tops I had 197 in both with the throttle plate at start up position.

May 30, 2012 | 07:14 PM

#15

jlasoftail

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Road Warrior

Joined: Oct 2009

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From: P.E.I. Canada

Quote:

Originally Posted by djl

Was this a dealer build? Are you sure you didn't have the 10.5:1 high compression pistons installed?

I know it doesn't add up. No argument there, but the facts are the facts. It was a dealer build, not high comp pistons, no head work, nothing other then what I stated. Maybe something not right with either my heads, pistons or cams, but besides a manufacturing error, I don't know how else to explain it.

May 30, 2012 | 07:15 PM

#16

jlasoftail

Thread Starter

Road Warrior

Joined: Oct 2009

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From: P.E.I. Canada

End result: So I changed the cams to a RS575, and so far so good. It was cold out today but so far I haven't heard a ping. I miss the real bull low power that I had before, but it's a great cam and has great mid and low power. I'm looking forward to some warmer weather to be sure the problem is gone, and I'm slowly bringing the timing back up, but so far so good. Also, I dropped from 220 ccp down to 200. Hopefully I can get rid of the octane boost! I also bet I made some great hp/tq gains, I might have to get it checked, they're just a little more to the right.