[Alexd]

Hi All,
Got my bike running but what is strange is when I start it it runs mostly on right cylinder, left cylinders sounds like it is running but not same as right. When I give some throttle left opens up and starts running. I did a bench sync few times already, checked float height and cleaned carbs few times with cleaner and originally soaked for few days in pines oil. I’m waiting to borrow a gauge to try syncing carbs on the bike. Also, when started right cylinder smokes a little and goes away.
Thank you.

 

[80cb400t]

How old are your carb boots? Any other vacuum leaks possible? Are the mixture screws at similar positions? Idle adjusted to 1200?

Have you made sure you've got similar compression in both cylinders?

Have you checked the coil and the spark plug boots with a multimeter?

Those things are a good starting point to check

 

[Alexd]

Compression pics are attached. Plug pics are attached.
I have a new GM coil, tested green and yellow wires for resistance, getting 0.5
Tested plug wires no caps getting 5.9 with caps 15.5
Idle set at 1200
Mixture screws are at 1.5 turns on both, I tried turning mixture screws either way and nothing changes. Jets are 75 and 110. Stock air box, original boots from carb to box in good condition no cracks and sealed around with hondabond between box and boots, new intake boots from carb to head, stock exhaust headers with extension connected to reverse cone mufflers (stock chamber was all rusted out along with stock mufflers).
Went for a ride and it stumbles on take off until about 3500-4000 if I roll on gradually but not if I just gunn it. After that is is fine.
I tested stator before, I had a earlier post about it some time ago and also tested cdi, don’t remember the readings but it was ok.
Also, still getting back fire on deceleration but it might be exhaust leaking, how can i check for that?
Sorry for suck a long post just trying to cover everything.
Thank you.

 

[66Sprint]

IF mixture screws have ZERO effect...The passages are still blocked/dirty......OR, you base setting is above idle range and you are using the mains

 

[Alexd]

Now that you mention idle. Sometime when coming to a stop in gear with clutch pulled in idle doesn’t drop back down, what would cause that?

 

[83XLX]

Yes, either your idle passage or the idle jet is stopped up. A hanging idle can be caused by either an intake leak or the carbs not being synchronized correctly.

 

[80cb400t]

Carbs out of synch also makes the 3500-4000 rpm stumble worse, if they're really off they can cause all kinds of problems

 

[longdistancerider]

The air cut valve diaphragms may be leaking air, impossible to diagnose without removing them. The lack of mixture adjustment sounds like that's the issue although dirty idle circuit or leaking insulators could also be the culprit.

 

[Alexd]

Looks like might be air cut valves. Decided to check if bolts were tight and all but 1 are stripped. Tried running a tap into them but still not holding. Will get little longer bolt and maybe it will be enough to grab more thread below where it is stripped. If that doesn’t work I’m screwed.

 

[Alexd]

Put in time serts in the stripped holes all good now, finally got the bike to start, synced carbs All was well last night. Today took it out had some idle issues, after few minutes at speed idle wouldn’t go back down stayed at around 3k, had to adjust it down. Bike backfires on decel. So still have to figure out carbs. Also, still have an oil leak I need to find and noticed head gasket and gasket between block and lower head weeping. Used reproduction gaskets. Getting very frustrated. Rant over.

 

[Alexd]

And so it continues. Replaced shifter seal again, carbs synced, started after some hesitation but ran really good. Took it to a bike night about 40 miles away, about 20 miles in started backfiring on decel and every time came to a stop it wouldn’t idle, had to rev it to keep it running. Got to bike night, noticed oil leaking again from the shifter seal. Noticed some fuel in the overflow on left carb. About 1.5 hours later time to leave bike won’t start, crank but no start, smell fuel but no start. Finally after few minutes of trying with choke and without it started but wouldn’t idle. Got it running and kept revving to keep it running and just went for it. Kept stalling on every light and few miles later it went back to idling fine. Now running ok but not great at speed doesn’t feel like it has all the power but most of it. So after all this need to figure out how to stop the leak and figure out carbs.

 

[longdistancerider]

Are you positive the shift shaft seal is leaking? If so then I'd guess that the shaft has a burr or gouge on it causing the problem. The left cover has a vent/bleed cut that will allow oil to go into that area if the crank seal is leaking. You might want to remove the cover, clean everything, throw baby powder all over the entire side and run it until the leak appears. Oil + powder makes a gooey mess where the leak is.

 

[Ebuddy]

Have you tried spraying carb cleaner around the carb while running to see if idle changes due to some un-diagnosed air leak that you missed the first few times?

 

[Alexd]

Found the source of the oils leak! Behind the front sprocket. I had a new outer seal there, popped it out inner seal I can spin by hand, I know to replace the inner seal I have to open the bottom end right? No other way? Or if I try just replacing outer seal it might work? Really don’t want to open bottom end.

 

[longdistancerider]

Just replace the outer seal. The inner will be fine. Now the fun of removing the seal. Drill a hole in the seal and install a wood screw. Now use a nail removing pry bar or similar tool. DO NOT insert anything between the shaft and seal to pry it out. You'll scar/gouge the shaft and it will always leak after that.


Use a section of PVC pipe to drive the new seal in. Don't worry about going in too far, it will stop at the right place, when the 4 little legs of the seal run into the inner seal.

 

[Alexd]

I replaced the seal and still leaking popped it out got a new seal and don’t want to put it back if I have to replace inner seal. Inner seal can be spun with a finger and oil is constantly sealing through it.

 

[longdistancerider]

The inner seal isn't a tight fit so it can spin, that's ok. The area between the 2 seals is an oil reservoir that's pressure fed from the pump to force oil into the output/countershaft lubricating the gears.
I would suggest taking a very close look at the seal run area of the output shaft, where the seal actually rides. You may have a damaged shaft, look for a scratch or gouge. If there is one then you need to replace the shaft since there's actual oil pressure on the backside of that seal.

 

[Alexd]

Update. Replaced the seal but now can’t get the bike started. Took carbs off and cleaned again, put in new float needles (bought extras just in case) and rechecked float level. Cranks but no star not even trying. Battery is good. Rechecked stator, alternator and coil. I have a gm coil on it.
Pulled plugs, plugs are wet. Put fresh plugs no difference. Checked for spark, looks good.

Test results:
Coil test on the primary side is .5 ohms
Secondary side is 5 ohms I know it should be 7.2 to 8.8 problem?
Plug end caps 15 and should be 5, new ngk resistor caps. Problem?

Stator 136, 85 and 208. Alternator is .6 so I guess that checks out.

Thank you.

 

[longdistancerider]

The 7.2K-8.8K ohm secondary resistance applies to the original coil, not the GM coil. I don't know what that resistance is or should be.
If you've got good spark and compression the only things left are fuel and ignition timing. Timing isn't adjustable or even changeable so that's out. Fresh fuel? Try starter fluid/ether?

 

[Alexd]

Got fresh fuel. Still nothing. Pulled plugs again and tested and now no stark. Should I start with new coil? Get Honda replacement or try another gm coil?