Rough running issues 1966 CL77

[eyedragaknee]

I'm trying to get the scrambler running. Having some issues. Maybe some input?

I rebuilt the carbs using stock jets & needle middle clip, floats set right, new cables,slides in right... 1/1/2 turns on the air screw. Tried different settings

Set valves, timing chain tension, plugs..

Set points using an LED to see where they open for sure and the static timing on both sides is right on. Put the light on it and it advances right up to the advance marks both sides. (Ed tuning recipe)

It starts first kick and idles all day long.

Mid throttle, it starts popping, full throttle it falls right on its face.

Seems to be getting OK spark. New battery.

Ran with the gas cap loose. Same problem.

Have filters on the fuel lines since the carbs were rebuilt so nothing is in them.

Open pipes and air filter tubes with dirtbike foam screen on them.(for now)

It just seems like the mid and full throttle isn't working at all.

Never did a compression check on it, but I would think it would still not run like that?

Ideas?

[davomoto]

Are the slides in the correct carbs? There is a R and L slide. The cut-out in the bottom of the slide should face toward air filter. Did you trim 1/4 inch from end of plug wires where cap attaches? Check plug wire ends at coil? If all of this checks out good, try doing a throttle chop test, and check color of spark plugs. They should be a nice cocoa brown, white too lean, black too rich. Please let us know what you find!

davomoto

[eyedragaknee]

Yep, did all that before but forgot to post it. Plugs look OK for as long as it has been running.
Slides are in right for sure. Carbs are synched using air screws and idle screw. It idles fine.

Carb Jets 38 and 130, Slide PW-20

I put a different set of needles in it tonight just to see if it made a difference in the mid throttle. They came in a CL77 "kit" and were longer and fatter. Bike hardly would run except on the choke and idle varies from nothing to real high off of the choke and then dies.

I put the stock needles back in and raised them one notch from the middle to see if that changes it good/bad and will ride it tomorrow.

I'm sure it is something simple, but I haven't found it yet.

thanks

[kustommusic]

Knee, I believeI would go back and make sure the low speed circut was good and clear of junk. Just my 2centz worth. Kustommusic

[eyedragaknee]

Pulled the plugs and it looks like someone $hit on them. Black sooty looking both sides. Not wet with gas, but major soot.

This is just from riding around the block maybe 3-4 times. Prob less than a mile or 2.

Going to do a compression test today.

I was hoping to just get it running and ride it till winter and then do the whole engine. Maybe that just isn't going to happen.

[davomoto]

Running rich. If the slow jet or passages are clogged, the bike will idle on the main jet. Turn air screw in to lean out, raise clip on needles to lower them.

davomoto

[eyedragaknee]

Thanks guys DM and Ed . I have some things to look at for sure.