Honda cx500c 1982 running problems

[rekievit]

test results, not good

After checking the valve clearances, new plugs, and resetting the cam chain tensioner we put the carbs back on.
Although the bike fired right up and sounded much better than before, the problem still persists.
The left exhaust was much hotter than the right (but the right was warmer than before) and after a short time there as some backfiring / popping noises. We could tell the right cylinder was still not really firing.
Our secondary gas can emptied quickly, seems to be very excessive fuel consumption now.
The bike will run on only the left idling strong at 1100 but the right will either fire and die or idle weakly at 800-900. We played with the sync and idle screws to no avail. Nothing really changed anything on either. The throttle stop screw does contorl the idle well though.

We need some help on how to fix this. The weather is getting warmer and we would love to get this bike up and running.

[rekievit]

Took the bike out after another carb cleaning and fitting a carb cleaner.
Its very hard to get going because of the one cylinder idle and when it is going there seems to be times when the second cylinder is kicking in.
Am i wrong in guessing its not (just) the idle circuit if the bike still wont run well on the road (obviously not idling any more) when using different jets than the idle circuit?

[DGXSER]

Not sure about this bike, but on the XS11 the same jets (pilot Jet) is in play up to about 3-4K RPM. That is when the main jet kicks in. I know for my bike, until it gets warmed up in the morning, if I kick the enricher off to early, it bucks and fusses inthe lower RPMs until I hit about 3K and then it will take off like a scalded dog.

[tarzan]

ok ok

sorry wrong post
Tc please delete

[rekievit]

also, when running only on the right (problematic cylinder) it will idle fine but when any throttle is applied, even a light touch it will die. It the choke is added the rpms will rise up then die back down.

[Cbass182]

Sounds exactly like the problem i had with my 79 cx500 custom...My carbs don't have the accelerator pump on them but otherwise they are the same. I cleaned my carbs like 4 times getting very frustrated...would idle after the first cleaning with new jets but only the left cylinder fired...the first few times of cleaning the carbs, the right cylinder wouldn't fire going down the road till i got up to about 4500 rpms er so...

Finally I took the carbs off and took out everything i could find including air cut offs, the top covers with the needle jet and slide and everything, the little black plastic bannana looking thing, the the float boal, floats, jets, rubber plugs, the thing under the main jets that takes an 8mm wrench, and under the idle jets are emulsion tubes that should be taken out and cleaned...and the idle air screws I took out (make sure when you take out the idle air screws that you get out the spring, the little washer and rubber o-ring and make sure they are in good shape)

I ran a guitar string through all the tiny holes in the emulsion tubes (don't do this to your jets...) and every hole i could find that the string would go in, in the carb bodies.

When you spray carb cleaner through the hole that the rubber plug covers, it should be spraying out where the idle air screws go a little bit...that took a bit of spraying and blowing out with a high pressure air nozzle on my compressor to get clean...

I then boiled the carb bodies still together in an old pot for 15 minutes or so.

Bench synced the throttle plates...

Soaked all metal carb parts in a can of chem-dip

Then i put it all back together, fired her up with fresh spark plugs, started the idle screws at about 2 360 degree turns out from all the way in then backed out both idle air screws until I could snap the throttle and the motor wouldn't hesitate/stall, made sure I had the clamps down good on the carbs for the manifolds and hey...doesn't run awesome, but gonna take it to someone to sync the carbs for me...and she should run great...

No more missfire on the right cylinder and no more backfiring/popping...

Hope this helps you...

-Chris-

[Cbass182]

Oh, I also replaced the air cutoffs...this can cause a bad idle and whatnot too...

Take em out and make sure there's no holes in em...

-Chris-

[rekievit]

Thanks Chris,
Yeah, we had them off and completely apart like you described but its good to hear you got that second cylinder running after some more cleaning.
The air cutoffs don't have holes which is good, but it looks like well have to clean again and again since I can't think of anything else that can be done.
Did you boil yours in water?
I think maybe we should switch all the needles, jets, and emulsion tubes between the two carbs just to rule out any possibility a po slightly widened something with a drill or wire.