Honda Cl 175 engine problems

ddx:dx · May 17, 2009

I'm having trouble with compression. The right side is low (70) with 10 cranks compared to the left (105). I'm at 3000ft elev. The left side runs, the right side won't.
Timings OK.
Sparks OK.
I've replace rings and had valves ground.
New head gasket.
When I put it together this last (THIRD) time, I checked the compression on the left with it running just on the left cylinder.
Idle(1500-3000 rpm) 70 psi
3000-6000 rpm it goes up to 110 psi
above 6000 rpm it drops down to 70 again.
So, what are your thoughts? Sticking valve? Warped head?

I can now take the engine out, get down to the pistons, back together in 6 hours....I'm not sure this is a skill I want to hone.

CB750F · May 17, 2009

What's the spec on the PSI in a Honda manual. It seems they are both to the low side but I don't know for sure. I'd double check your valve timing and valve clearances (with the engine dead cold) before R&Ring the engine again.

CB750F · May 17, 2009

Quick search and I found this.

Acceptable limits according to Clymer's manual are 140-170 PSI, no oil.

http://www.obairlann.net/reaper/motorcycle/servicelog/73cl175.html

This guy has a 73 CL175 so it should be the same. Try putting a small amount (like a tablespoon) of engine oil down the plug hole and retest. That will help seal the rings and if it goes up you're rings aren't sealing as well as they should. if it stays the same or only increases a little then something else (valves or head gasket or valve timing) is amiss.

limp1969 · May 21, 2009

Your comp is low on both cylinders, 140 psi is what it should be. But it can also need break in time to seat. Are all valves set to spec.002 in .003 ex

Honda Cl 175 engine problems

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