Low compression and poor running; 2012 FLHR 103.
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Stage I
Joined: Aug 2015
Posts: 1
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From: Midwest, US
Low compression and poor running; 2012 FLHR 103.
Greetings, everyone,
Caught wind of what could be a pretty serious problem yesterday. After noticing some poor running last year, I decided to check compression on my Road King before getting it out again this year and the results were troubling: Rear cylinder was ok at 160 psi, however; Front cylinder was 90 psi. ****.
So, I noticed a tapping noise last year that developed and seemed to get worse over time, as well, there was lots of decel popping, no matter to what setting I had my tuner (Vance and Hines FP3).
So, I'm hoping I've got a bad lifter and that it hasn't become a valve problem. Pretty disheartening, especially because these days I'm a broke student and don't have the resources I used to throw at it.
Could anyone offer some direction on how to go about diagnosing more closely what the problem that needs to be addressed is before I go spending money I don't have trying to fix it?
Going to have to trailer it to a friend's shop to work on it...not until the semester is over. Yay.
Thanks in advance.
Caught wind of what could be a pretty serious problem yesterday. After noticing some poor running last year, I decided to check compression on my Road King before getting it out again this year and the results were troubling: Rear cylinder was ok at 160 psi, however; Front cylinder was 90 psi. ****.
So, I noticed a tapping noise last year that developed and seemed to get worse over time, as well, there was lots of decel popping, no matter to what setting I had my tuner (Vance and Hines FP3).
So, I'm hoping I've got a bad lifter and that it hasn't become a valve problem. Pretty disheartening, especially because these days I'm a broke student and don't have the resources I used to throw at it.
Could anyone offer some direction on how to go about diagnosing more closely what the problem that needs to be addressed is before I go spending money I don't have trying to fix it?
Going to have to trailer it to a friend's shop to work on it...not until the semester is over. Yay.
Thanks in advance.
Tourer
Joined: Sep 2014
Posts: 279
Likes: 315
From: Southern Vancouver Island
If you had a tapping noise previously that was getting worse, I would check your lifters and cam. Easy enough to collapse your pushrod tubes and check the front cylinder pushrods for excessive lash with the front piston at top dead center on the compression stroke.
With both front cylinder valves in the closed position, if one of the pushrods has a bunch of excessive lash, you've got a collapsed lifter or maybe an issue with the lifter roller or cam itself. That, or if you have adjustable pushrods in there, maybe one of the pushrod locknuts has backed off and the pushrod is out of adjustment. That would be the best case scenario. Good luck.
With both front cylinder valves in the closed position, if one of the pushrods has a bunch of excessive lash, you've got a collapsed lifter or maybe an issue with the lifter roller or cam itself. That, or if you have adjustable pushrods in there, maybe one of the pushrod locknuts has backed off and the pushrod is out of adjustment. That would be the best case scenario. Good luck.
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