Help with CL350 Starting Issues (everyone's favorite!)

This is a bit of a long story/scenario so here's the cliffs notes:

-Tore down and rebuilt a 72 CL350. All new ignition bits with electronic ignition plate. Replaced head gasket and above on the motor. Didn't touch the crank/pistons or transmission.

-Started up after some tuning and ran great initially. While I was out on my first longish ride I stopped for a bit and it wouldn't restart. Towed it to a shop and they said the timing may have slipped and it sounded like it needed a new head gasket. I tore the motor apart again and replaced the head gasket. The noise they heard was actually from the gasket of the cam bearing housing leaking (oh well).

-Didn't seem to want to run too well after the second rebuild. It would start up and run pretty good, then start to blow white smoke out the cam housing after about 10 minutes. Sometimes it would start up a few times in a row and others I'd need to put some gas in the cylinders. It also wouldn't want to rev much past 5k RPMs easily. I thought maybe the carbs got dirty from all this so I pulled them and cleaned them thoroughly (they were dirty) and replaced some parts.

-Now it's all back together and after several attempts I got it started but it's definitely misfiring. I tried to rotate the ignition plate but didn't see any improvement. Please help me out as my brain is racked on this. I'm about to tow it to a shop but I'd much prefer to repair on my own. I have strong spark and the carbs are both getting gas/spraying. The back pressure out of each exhaust pipe is the same.

Thank in advance!

Did you re-check the cam timing. the chain may be loose and slipped a tooth?

I hope you were using a timing light or something, and just not rotating the breaker plate randomly....

If so, set the timing correctly...but after you check the cam position.

Last time the cam timing was checked it was solid. Never had issues with the tensioner previously and it was set at the right point.

Are you certain the points advancer cam isn't 180 degrees off?

i'm very curious as to the "noise they heard" comment and therefore the changing of gaskets.?.....

need more clarification too.....ran then died right? but would start once in a while? enough for garage to
hear something? yeah?

revs to 5000 but not past? have you done that and then pulled the plugs and looked at them? is one wet? and one dry?

when you say you replaced electronics, does that mean coils too or are the original?

did you pull the advance mechanism and see if it's free to move?

you say you have spark, you have gas(at least in idle circuit but problems at5000) you have compression(i'm guessing) so what's left is timing.
if it runs at idle then it's timed within the oops period(basic timing) do both pipes get hot? did you set left cylinder timing and then right cylinder points gap
properly? the 350 timing is my nemesis running back and forth getting it set up statically. but sounds like it could be an issue. (this is purely based on what you've said and does not take into consideration starved for gas when it opens up, torn carb needle boot if it's running CV's therefore losing vaccuum, carb boot leak, plugged something or other. if it isn't running at all at this point, disregard the above and start from scratch, enough juice in battery, static time again, clean carbs thoroughly, set valves and inspect inside valve covers for a black rubber bits within the oil(if you find this, it's your cam chain tensioner deteriorating), check your coils....with that, it'll run

iContango said:

Are you certain the points advancer cam isn't 180 degrees off?

Click to expand...

Bike won't run at all with the advancer 180° out.

I think you're fighting multiple problems. Retime it and then double-check with a strobe light. While you're there, run a compression check to make sure you're not having problems related to that.

Once timing and compression are checked (and fixed, if needed) then you know the problem has to be with fueling.

The coils, wire and plugs are all brand new. The compression is perfect as well.

I agree this must be a timing/fuel issue at this point.

Any idea why it would intermittently start? If putting fuel directly in the cylinders gets it to start, does that indicate a fueling issue for sure or could it still be timing?