[bigring911]

Hi,

thanks for taking the time to read this and hopefully offer some suggestions, experience and advice.

It's a '72 Honda CL350 that I've had for about a month or so now. It's in good shape but not running. The PO had rebuilt most of the engine - he had the cylinders honed with new Bore Tech pistons,rings and valves (valve seats were lapped) - he had purchased a Triumph and never got around to getting this going again when he sold it.

Since I've had it I discovered that the PO had not set the timing of cam-crank shaft properly nor the valve timing.

I did a combustion test I had the carbs off, as well as the header/muffler. I did the test five times, all cold (the bike is not running) and pretty much got the same results each time with both cylinders. 1st kick - 45-50 psi, 2nd kick - 60 psi, 3rd kick - 90 psi, 4th and 5th kick both cylinders topped out at 120 psi.

I'm hoping that the only reason it's not getting up as high as it should be is due to the carbs & muffler being off and it being cold - my fingers are crossed that I don't have to tear it apart.

Any help would be appreciated.

Thanks Fellas!

 

[J-T]

Having the carbs off will give you higher compression readings due to reduced intake restriction, but not a lot more than with the carbs and choke open and the air filters removed.

120 on a cold engine after a rebuild isn't bad. Put it together and break it in, then take a reading on the warm engine.

You have corrected the cam timing, haven't you?

 

[bigring911]

Yes sir, I did. I'm putting in a new battery, doing the points and will see how it goes from there. I'm hesitant to tear it down before getting it going first.

 

[slofut]

Yes sir, I did. I'm putting in a new battery, doing the points and will see how it goes from there. I'm hesitant to tear it down before getting it going first.

Don't tear it down, you could be riding it instead! I'm betting it's fine.
Do valve adjustment, cam chain and points/timing as per the manual first. If you're ocd like me squirt some oil on the cam lobes thru the adjustment holes before you spin the motor much.

 

[bigring911]

Good idea. Will give that a go.

Thanks J-T and Slofut - much appreciated!

 

[-alan-]

Don't tear it down, you could be riding it instead! I'm betting it's fine.
Do valve adjustment, cam chain and points/timing as per the manual first. If you're ocd like me squirt some oil on the cam lobes thru the adjustment holes before you spin the motor much.

Definitely don't tear it down. You might just have a low-reading gauge - or could be something simple like the valve clearances being out a tad. As the guys suggest - get it going, put it through a proper run-in procedure, see how it runs, and whether there's any other symptoms of something being amiss. You can test the compression again at that stage if you still have concerns. Its always easier to diagnose problems on a running engine, than think about the myriad of possibilities on a non-runner.

 

[bigring911]

Thumbs up. Thanks Alan - that's what I'll do!

Cheers Fellas