210 psi front, 260 rear, WTF?
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Grand HDF Member
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From: Tampa
210 psi front, 260 rear, WTF?
If you're following my build you'll know what I'm going. Basically I developed what i"m not sure is a problem or not. The bike has a very pronounced metallic knock at idle and light acceleration, but it goes away once the bike is moving along well. I did a compression test, not motor, WFO throttle and that's what I got. What could cause this?
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Grand HDF Member
Joined: Nov 2009
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From: Tampa
Whoever the ******* was that put the pushrods in they didn't set the intake pushrod on the rear cylinder. Never using that builder again...
Still got a weird knock at idle and light throttle, not sure if it's just noisy valvetrain or I smoked a piston and that's piston slap. Might hafta tear her down for an inspection.
Still got a weird knock at idle and light throttle, not sure if it's just noisy valvetrain or I smoked a piston and that's piston slap. Might hafta tear her down for an inspection.
Stellar HDF Member
Joined: Aug 2013
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From: Texas
Seems like a lot of compression for pump gas, but my building experience is with in line 4s, not Harleys. 210 is normal for a in line 4 with 13.5 to 1 pistons. Not apples to apples, just my experience
Seasoned HDF Member
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From: Ohio
Valve train noise is a tick and will be louder at idle and mostly when the engine is hot from oil thinning.
A aggressive cam puts out more of a metallic clacking sound heard at idle and low rpms. It will make the same noise on all 4 cam lobes, not just the front like a oiling issue.
If you have a Andrews or Woods cam you need to set the lifter depth to .150 instead of .100 like a common cammed Evo, a aggressive cam noise can be tamed by a deeper setting.
Seasoned HDF Member
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From: Poolville
Typically a cam that has not been timed properly to the crank will make a difference in compression from front to rear. Roughly 30+ psi. You have 50 psi,
that's a lot and for it to be as high as it is it sounds as if it was advanced a tooth...
that's a lot and for it to be as high as it is it sounds as if it was advanced a tooth...
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Grand HDF Member
Joined: Nov 2009
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From: Tampa
That's what the issue was. My rear intake was completely out by the whole travel of the lifter. Basically I never preloaded the pushrod, then when it ran the lifter bled down but there was a lot of play in the pushrod. Due to this now the intake duration is narrower, and also less lift. Sooner intake close causes increased cranking compression.
I fixed the pushrod and that fixed the compression issue.
I fixed the pushrod and that fixed the compression issue.
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Seasoned HDF Member
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