Leak down test issues
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From: Honah Lee
https://www.hdforums.com/forum/ignit...-injection-55/
Title it. No combustion in rear cylinder.
Then your details in body.. I have spark and I have fuel.
Be sure to give bike details, year model and Harleys letters. Milage, tuner, modifications, what you have done , when this started......ect
Last edited by Jackie Paper; Sep 26, 2025 at 01:03 PM.
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From: Canada
If compression test shows 145 on each cylinder there is no need for a leakdown test, the engine is good.
A leakdown tester can help you find out where an engine is losing compression, but other than that it is no more useful than a compression test.
Is there an issue with the engine that made you do a compression test?
A leakdown tester can help you find out where an engine is losing compression, but other than that it is no more useful than a compression test.
Is there an issue with the engine that made you do a compression test?
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From: poway
I had an issue with engine power due to fuel filter collapsing and restricting fuel flow significantly (https://www.hdforums.com/forum/ignit...ry-issues.html). I replaced fuel filter and I now have good fuel flow and pressure but engine runs really hot (after 20 minutes of riding, even though in the city, engine was reaching 280F, and outside temperatures were around 70F) so I wanted to do some basic checks.
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From: georgia
Running hot and lacking power are the classic symptoms of a sumping issue. I suggested you check that early on. It’s by far the easiest thing to check. It takes all of 3 minutes to either pinpoint the cause or eliminate a possibility.
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From: Canada
Would sumping issue start out of the blue? Bike was running fine for over a year and all of a sudden started having issues. And there was definitely issue with fuel flow due to fuel filter that was now fixed.
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From: Honah Lee
It a cheap check to see what the injectors are doing. Most GM have a replaceable screen in the top of them.
And a simple box cut to hold tjem and a 12 battery to check spray pattern after removing screen..
Thats a hot running TC. I have never seen above 160 oil temperature on the interstate with outside temperature at 95F.
Was that oil at 260?
My last overhaul was a 93 4 cylinder YJ Wrangler with 300k on it. Was still running fine till it lost a freeze plug under the exhaust manifold and smoked it.
I popped the screens out of the injectors, reverse sprayed the wire mesh with throttle body spray cleaner.
Fired the injectors with my old battery charger and used a vacuum boot with a drilled hole in it for the cleaner spray straw to spray thru injectors.
Pattern looked good to me.
Old YJ now has 320K on it and runs good. Granddaughter used it for two year of college and nursing school.
Real easy to check a softail for sumping. Just cut it off, pull over and check the dip stick.
My bike until I gave it to my oldest son drained the bag setting 6 months between rides for 5 years. A few miles of easy riding fixed the issue.
And a simple box cut to hold tjem and a 12 battery to check spray pattern after removing screen..
Thats a hot running TC. I have never seen above 160 oil temperature on the interstate with outside temperature at 95F.
Was that oil at 260?
My last overhaul was a 93 4 cylinder YJ Wrangler with 300k on it. Was still running fine till it lost a freeze plug under the exhaust manifold and smoked it.
I popped the screens out of the injectors, reverse sprayed the wire mesh with throttle body spray cleaner.
Fired the injectors with my old battery charger and used a vacuum boot with a drilled hole in it for the cleaner spray straw to spray thru injectors.
Pattern looked good to me.
Old YJ now has 320K on it and runs good. Granddaughter used it for two year of college and nursing school.
Real easy to check a softail for sumping. Just cut it off, pull over and check the dip stick.
My bike until I gave it to my oldest son drained the bag setting 6 months between rides for 5 years. A few miles of easy riding fixed the issue.
Last edited by Jackie Paper; Sep 26, 2025 at 06:05 PM.
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From: poway
Would it cut out one cylinder?
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From: georgia
The person that said that is not the OP. I was responding to the OP which also has another thread about low power and overheating.
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From: poway
The motor could definitely sump if the scavenge pump ate something it didn't like..
Last edited by Max Headflow; Sep 26, 2025 at 06:15 PM.
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