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CVO Technical => Twin Cam => Topic started by: MGB on March 20, 2017, 11:13:52 PM
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'Hey guys. I have an '04 Screaming Eagle E Glide with 70 k miles on it. Just recently, the engine has started skipping. The rear cylinder is not firing all the time at idle. Did a compression test with these results: Both plugs out: the front cylinder hits 150 lbs consistently with WOT and with no throttle. The rear cylinder hits 70 lbs with a few revolutions and then all of a sudden, it hits 150 lbs.. I release the pressure guage and try it again and get the same readings. There seems to be no pattern when it hits 150 lbs., sometimes it will turn over a few more or less times before it hits 150 lbs. AND, to complicate things, when actually riding, anything over idle, it runs smooth as can be. No skip at all and plenty of power. All this with the engine cold or hot. The bike has around 70K miles on it and still runs strong, just don't idle too good. The engine has never been worked on or modified in any way except at 30 k miles, I had the dealer install a new screaming eagle cam chain tensioner with high flow oil pump and I just put in an Axtell oil bypass unit which did raise the oil pressure at all RPMs. The skipping was before the oil bypass unit was added too . I'm thinking that the exhaust valve may be sticking or maybe a bad hydraullc lifter, something along those lines. Anyone have any ideas or thoughts as to what might be causing it?Thanks
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My guess would be a loose or broken valve guide or maybe a slightly bent valve.Remove the exhaust and look into the exhaust port to see if there is any evidence of the guide moving. Is there any oil consumption?
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No oil consumption and the engine does not smoke.
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Typically you will have some smoking or oil consumption with a loose or broken guide. How do the plugs look? I would put an inline spark tester on the rear cylinder to see if it is firing consistently. When you say the rear is not firing how did you determine this? Are both pipes getting hot near the head at idle?
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I had the same problem. had two dealers look at it and replaced all kinds of things. it came down to the harness to the fuel injectors. one had a break in it and when the engine shook at different rpm's it caused it to miss. so glad someone figured it out. ;D
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I had the same problem. had two dealers look at it and replaced all kinds of things. it came down to the harness to the fuel injectors. one had a break in it and when the engine shook at different rpm's it caused it to miss. so glad someone figured it out. ;D
An electrical connection to the fuel injectors would not effect the compression to jump from 70 to 150 psi. 150 psi is quite low compression and 70 psi is not enough compression for the cylinder to fire. If you are confident the compression readings are accurate, I would focus the diagnostic on determining the reason for the low compression. A valve sticking in the guide could cause periodic low (70 psi) compression without necessarily showing smoke or oil consumption.
Curious, do you still have the original cam/crank tensioners in the motor?
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You might consider a leakdown test before you did much else. Any historic or current codes in the speedometer ?
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Hey Guys. Still chasing the skipping engine problem. What compression reading should I be getting on a factory, stock, 2004, 103 ci. screaming eagle engine? Did the 103 engines in '04 have an "Automatic Compression Relief" feature? Is the ACR used on both cylinders? Read somewhere that the ACR is controlled by the ECM. If that's the case, and there is an ACR, maybe the ECM is operating the ACR falsely. Does anyone have a engine service manual that might show an ACR on the 2004 103 engine? What do you guys think???
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Hey Guys. Still chasing the skipping engine problem. What compression reading should I be getting on a factory, stock, 2004, 103 ci. screaming eagle engine? Did the 103 engines in '04 have an "Automatic Compression Relief" feature? Is the ACR used on both cylinders? Read somewhere that the ACR is controlled by the ECM. If that's the case, and there is an ACR, maybe the ECM is operating the ACR falsely. Does anyone have a engine service manual that might show an ACR on the 2004 103 engine? What do you guys think???
While reading this post the ACR was what came to my mind first too. If it does have them maybe the rear one could have become intermittent in its operation. Maybe the small internal return spring which holds the valve plunger up when not activated has failed causing it to hang down in the open position causing your low reading then it gets slammed shut by the pressure your generating by through your compression test. :nixweiss: :nixweiss: :nixweiss: Just a wild guess!
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Cvo 103 engines do not have acr's
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My bone stock '05 cranks in the low 150s
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CCP on the 103's was in the 150's. It was a very low compression motor due to the 53 degree intake close of the 253 cam and HUGE ~96cc chambers
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Hey sadunbar, I had a harley dealer change out the cam chain tensioner at about 30k miles. They put in a new screaming eagle cam plate with the newer style oil pressure chain tensioner and a new high flow oil pump. thanks for the replies
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Does it have EITMS? Not sure if they did it on 04s but 'runs fine at anything over idle' points to EITMS problems turning that real cylinder into an air pump at idle and kicking it back on when you go >1200rpm.
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The 2004/2005 models have a simple EITMS that doesn't shut down the rear cylinder like late models. Basically the system on the earlier models just made changes to idle speed and ignition advance at idle when the engine temperatures exceeded set criteria, which culminated in what was called "skip fire" when the temps got extreme. That meant both cylinders would be caused to "miss" to reduce the amount of combustion heat being produced. The EITMS isn't the problem on this particular bike. Those models also don't have compression releases, so that also is not the problem.
The big elephant in the room is the intermittent loss of compression on the rear cylinder. Until that is addressed, all the other theories being thrown around are irrelevant. Where does the OP stand on solving that?
Jerry