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Compression testing

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Old Apr 4, 2015 | 08:45 PM
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Default Compression testing & Valve Train Noise

Weathers been crap & have only pulled 1 vtune session. Decided to compression test after swapping cames to the andrews 57 and going w/cometic .027hg.

My intial run on vtune showed just the front cylendar being lean. Valve train is quiet on start up but after warming up seems to pickup some noise. Also seems lounder in the 2500 rpm and up.

Warmed up the bike for about 5-8 minutes. (about 50deg outside)
Disconnected Coil
Pulled both spark plugs
Battery at full charge and on battery tender
Ran compression tests and pull ~120 on each front & rear cyl
turned it over 4-6 times, at which point it stops increasing.

Much lower that I expected ~180

Bike seems to run good, but 120, am I doing something wrong or possilble issues that just havent fully surfaced?
 

Last edited by rgr357; Apr 8, 2015 at 09:58 PM.
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Old Apr 4, 2015 | 09:20 PM
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Did you have your throttle plate 100% open and no air cleaner, basicallly no restrictions.......
 
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Old Apr 4, 2015 | 09:40 PM
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It's a 103 so I'm going to assume it has automatic compression releases.

Did you disable them?
 
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Old Apr 4, 2015 | 11:51 PM
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Originally Posted by 98hotrodfatboy
Did you have your throttle plate 100% open and no air cleaner, basicallly no restrictions.......
Yes pulled the AC and opened throttle 100% before hitting the starter.
 
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Old Apr 4, 2015 | 11:54 PM
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Originally Posted by senna
It's a 103 so I'm going to assume it has automatic compression releases.

Did you disable them?
Correct, 103, its a 2014 FXDWG

I did not disable the ACRs.... I presume to just pull the plug on them. Ill try it tomorrow and let you know, but that makes perfect sense, I just didnt think of it.
 
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Old Apr 5, 2015 | 07:03 PM
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Was able to run through the entire process again this time pulling ACRs after warming up etc.

Measured 185psi on both front and back cyl!!!

A little higher that I thought it would be, Very pleased with results. Head volume or cyl deck hight must have been better than I thought. I'm at 2900 on an overcast day 55degs.

Thanks for helping point me in the right direction!
 

Last edited by rgr357; Apr 5, 2015 at 07:08 PM.
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Old Apr 6, 2015 | 09:00 AM
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Originally Posted by rgr357
Was able to run through the entire process again this time pulling ACRs after warming up etc.

Measured 185psi on both front and back cyl!!!

A little higher that I thought it would be, Very pleased with results. Head volume or cyl deck hight must have been better than I thought. I'm at 2900 on an overcast day 55degs.

Thanks for helping point me in the right direction!
That should make you feel a little better.
 
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Old Apr 8, 2015 | 09:16 PM
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Default Valve Train Noise

Finally had a chance to go for another ride the other day.

Sounds great on inital startup but starts to get valve train noise as it approaches full temp. Seems like the hotter it gets the louder it is. Also not so bad at idle but around 2400 it ramps up, again not so much when its on warm up but certainly louder than it should be when hot.

Otherwise sounds and runs great... any indication of based on those symptoms?

oh yeah, I tried the screwdrive test but was hard to pin point other than somewhere under the rocker cover. Also seems louder on the left side of the bike and Im not just saying that cause the exhaust note/intake. Sound can do odd things tho so who knows.
 

Last edited by rgr357; Apr 8, 2015 at 09:57 PM.
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Old Apr 9, 2015 | 05:00 AM
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After working with agressive-ramp cams now for almost 20 years, we have found that by loading the lifter to .140-.150", valve train-related noise seems to be very minimal, in any.
Scott
 
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Old Apr 9, 2015 | 08:06 AM
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After a top end rebuild this last winter, I have been fighting with lifter noise when the bike heats up. I have adjusted the pushrods several times according to the S&S instructions, but couldn't quite get it right. My solution- and guys please feel free to correct me if what I did was wrong- was to adjust them hot. I rode the bike for a few miles to get it up to temperature, then put on a pair of leather gloves and adjusted the pushrods again. I tightened them up to where they had no play, but could just barely be turned with gloved fingers. The noise is now gone, and it seems to be running fine this way.
 
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