Top end big bore - compression not what it should be?
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Road Master
Joined: Apr 2017
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From: out there
It has the stock headers and the original old school screaming eagle slip ons. Very similar to the S&S tapered turbo slip ons.
I'm not too concerned about maximum power, just trying to figure out what could be causing a loss of compression.
Thanks
I'm not too concerned about maximum power, just trying to figure out what could be causing a loss of compression.
Thanks
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From: poway
What bike?
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From: san antonio
Seasoned HDF Member
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From: poway
Because KB does not make 3.938" pistons? The pistons are cheaper than Wisecos and pretty good quality. I know Larry has been bugging KB to make 98s but so far they haven't. (Maybe now?)
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Road Master
Joined: Apr 2017
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From: out there
Thanks djl, you say not to worry about the 10 lbs. OK, but what if my thread title was - S&S 570 95" build lacks power? The only reason I checked ccp was because it just doesn't feel like it is making the tq/hp it should. It feels sluggish.
If I do indeed have only 190 psi, should I maybe consider a cam change to get the best out of this build? Maybe an tw-57 - like the old 37 cams with the extra lift?
Thanks
If I do indeed have only 190 psi, should I maybe consider a cam change to get the best out of this build? Maybe an tw-57 - like the old 37 cams with the extra lift?
Thanks
Tourer
Joined: Oct 2010
Posts: 406
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From: NW MO
Slop in the crank sprocket can throw ccp off a lot if its retarding the cam. 100 hp is a pretty optimistic hp/ci goal with stock heads, and a B motor to boot. Youd honestly be lucky to make 100 hp with a 103 A engine and a good dyno tune, which is the other thing that you dont seem to have. Can easily lose 10+ hp with lack of tuning.
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Thread Starter
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Road Master
Joined: Apr 2017
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Likes: 92
From: out there
Slop in the crank sprocket can throw ccp off a lot if its retarding the cam. 100 hp is a pretty optimistic hp/ci goal with stock heads, and a B motor to boot. Youd honestly be lucky to make 100 hp with a 103 A engine and a good dyno tune, which is the other thing that you dont seem to have. Can easily lose 10+ hp with lack of tuning.
without proper dyno tuning I can't expect too much.
I guess the only question I have left is whether to leave the 570 cams in with a little less compression than they'd like, or swap them out for something that is optimised at 10:1 comp might give me more usable torque.
I was considering the Andrews 57 (same as 37 with more lift)....
Thanks
Last edited by Adam76; May 24, 2022 at 04:14 AM.
Seasoned HDF Member
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From: poway
OK fair call.
without proper dyno tuning I can't expect too much.
I guess the only question I have left is whether to leave the 570 cams in with a little less compression than they'd like, or swap them out for something that is optimised at 10:1 comp might give me more usable torque.
I was considering the Andrews 57 (same as 37 with more lift)....
Thanks
without proper dyno tuning I can't expect too much.
I guess the only question I have left is whether to leave the 570 cams in with a little less compression than they'd like, or swap them out for something that is optimised at 10:1 comp might give me more usable torque.
I was considering the Andrews 57 (same as 37 with more lift)....
Thanks
Doing that isn't going to give you more power. Low end will pick up some..