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Engine Mechanical TopicsDiscussion for motor builds, cams, head work, stripped bolts and other engine related issues. The good and the bad. If it goes round and around or up and down, post it here.
Recently installed Cyclerama CR 570-2 cams, Hylift Johnson lifters,SE tapered adjustable pushrods and Crusher Mellows slip ons. Already had a stage 1 with VH PDs, SE air cleaner, and Bassani DNT slip ons. I have to say I might be just a little disappointed with my results. Essentially just a 4 hp and 4 tq gain with the cam install vs my stage 1. Based on what I see others get out of this setup, I feel 15% hp and tq were left on the dyno.
I spoke to Durwood at Sheffer Performance a couple days ago who recommended a compression test to see if one or the other cylinder might be off indicating the cam was misaligned. So I purchased a tester and tested. Warmed up the engine by idling for a short while. 168-170 each without ACRs, and 112 rear and 120 front with ACRs. Throttle was propped full open.
Rode the bike to work today, so when I got home I decided to do another test. Thought maybe the engine was not warm enough the first time. Repeated the test today after riding for 45 minutes or so. Same result - 170 no acr. Then I put a little oil in each cylinder and re-tested. About 205 each. I also noted that during the no-oil tests the pressure would hit low then a bit higher then max out at 170. Looking at the service manual, this by itself indicates a ring sealing issue. Should I consider a leak down test?
I'll offer that I bought the bike used in July of 2016 (Florida) and I bought a 2-year ESP warranty. Wondering if I should have the dealer do an inspection and if found low I should do warranty claim. Not sure of the potential problem or solution (rings, cylinders, etc). Only 8200 miles on the bike. I do not notice much oil consumption and the bike rides ok with the new cams and tune. While I want to maximize my performance I am now concerned I may have a bit of a problem started.
tried finding that cam in the bigboyz caluation to see what compression would roughly be but its not listed, any chance that cam is for compressions over 10.5:1 or higher. which would make your compression numbers to low.
Any Cam with overlap will give you low cranking numbers.
The exhaust is going out the door (valve).
But this is a good thing for a proper tunned bike up and running on cam.
The leak dwn test will tell you if you are chasing your tail.
You never stated what motor you have. A 103"er has 9.6:1 compression and a 96"er has 9.2:1 and with the intake close of 32* your ccp should be in a 103"er/187 and a 96"er 177. So if it's a 96"er you right about where you should be... And an overlap of 14* is very low and should not affect ccp... Intake closing is what determines ccp. However a 30 psi increase in ccp with oil would indicate a ring issue and would require a leak down test. Allowable is 10%. anything over would indicate worn rings... Do you know if the used bike you purchase was stock or not?
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low CCP: poor ring sealing?
