I just did a compression test on my bike and found that the front cylinder has only 15 psi ! But the back one has 90 psi, what could be the problem? Could it be worn rings? And if so will changing just the rings fix the problem? Could it be a sticky pushrod not opening the valve? And if the timing was off would that give a low compression reading too? Any suggestions of where to start would be great!

 

worn rings/cylinder wall, valve sticking open, burnt valve seat, cam timing off. do a leak down toest to see where the problem lies. you can take an old spark plug, knock out the ceramic piece, weld on a male air tool connector and plug into an air compressor. air coming out exhaust or intake indicate valve problem, through crankcase indicate rings/cylinder wall.

 

What symptoms caused you to do the compression test in the first place?

 

Well it was running rough and I just got the bike so I wanted to check it anyways, plus when I took the plug out of the front cylinder it was coated with oil.

 

sounds like cylinder/rings to me. im not an expert but 90 psi on the rear seams low to me as well

 

Sounds like a rebuild is in your future. You can get lots of help on the Ironhead forum. https://www.hdforums.com/forum/ironhead-66


Good luck!

 

If theres oil then you've got blow by, which usually leads to bad rings

 

ok that's great that we narrowed it down to the rings I thought that's what it was,,now my next questions. 1.) If I change just the rings, will this help fix the low compression? 2.) Do I need to change the pistons too? Or can I get by just changing the rings if the pistons look good? Thanks! Im getting there!
I already have the tank, exhaust and carb off.

 

If the pistons check out good you can re-hone the cylinders and install oversize rings.
Have the pistons checked by someone who knows what they are doing, it's not just a visual check and after all the work it would be a drag if you had to tear it all apart again.
You should talk to Dan at NRHS, he can advise on this best and hook you up with good quality parts.

 

Thanks for the reply, I will post more info after I tear it down and inspect the pistons and cylinders then go from there.