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I am actually having kind of the same problem... although I have to rev it a little harder to get the other cylinder to fire. I was thinking maybe your throttle sync might be off a little, but if the carb clean took care of it... sweet!
 
Discussion starter · #23 ·
ARGH. so after i cleaned the carbs it was idling on both cylinders (although definately favoring the one that was working before) for about a week and then poof my bike dies at a stoplight and now only idles on one clyinder again. i cleaned the carbs again and still nothing. i switched the plugs and nothing. i'm definately getting spark but no love at all from that cylinder.

help!
 
quote:
is there some kind of poor man's compression test i can do? i don't have much in the way of tools...
you can do a leakdown test, will tell you if the rings are holding at all. With the suspect cylinder at top dead center remove the spark plug and using a old plug (with the center knocked out) pressurize the cylinder to 5 psi and hold it. see how long it takes for the pressure to leak out. It should not be instantaneous but rather take a couple of seconds.

However, I am still leaning toward it being carb related. How clean is your tank and how old is the gas in it. That tank inside should be spotless. If cleaning the carbs caused the problem to go away then I would continue to follow that logic. It sounds to me like a clogged idle circuit and you have dirty fuel. Also check for kinks in the line leading to that carb, sometimes the vacuum can pull fuel through where it would otherwise not flow.
 
im siding with geet here. if it went away before, id keep looking at fuel delivery. although, a compression checker is cheap, and easy to do. and will give you a good idea of overall engine condition. but id keep looking at gas.



jc

"tex, if your bikes a cheater, its not a very good one"
 
Thought I'd throw in my pair...

Both sides have to be essentially balanced to run. If one's slightly closer to tuned, it pulls the other side and that side shuts down. You may find that if you pull the spark cable on the running side, it'll run on the other side - often the case.

So I'd try two things. One, I'd check the timing, a fairly easy process on that machine even without a timing gun. Once you've got that perfect, I'd spray something combustible into the non-running carb for a couple seconds and see if it runs on it. If so, rebuild your carb again, paying particular attention to the channel behind the air mixture screw. Set the screw to spec (anyone remember what it is for that machine - 1.25 out? 1.5 out?), crank up the idle screw and see if you can convince that side to go.

You're suffering the standard old Honda malaise. Don't give up, carb tuning is a bit of a black art.

A
 
Discussion starter · #30 ·
well i broke down and took it to a mechanic. he pulled the carbs off and said they were really dirty. i went over to his shop to check it out and he showed me a jet and said look at how dirty that is even after it's been soaking in carb cleaner. i thought it was clean when i put it together, but never having seen a clean carb i'm not surprised i was wrong. at least this guy seems cool. i can't believe how hard it is to find a mechanic that'll work on an old honda in seattle.
 
Discussion starter · #32 ·
well... although my new mechanic is a good guy (he's been working on my bike for a couple weeks and is only charging me for 2 hours) he seems to be stuck. cleaned and adjusted the points, the valves, the timing, the carbs, all to no effect. it's got good compression. he says the spark is weak but can't figure out why (unless both my old coils and the new (to me) ebay coil i bought are all bad which seems unlikely.) anybody got any ideas? i miss my bike!
 
you let out a clue...rusty tank. clean it as best you can...nuts/bolts/whatever shaken around violently works (count the pieces going in ot make sure they all come back out) flush the heck out of it over and over again. install fuel filters which allow you to see the pieces of s#!t accumulate, clean the idle circuits (both carbs) again (as discribed above) and call us in the morning.
parks
 
I am having trouble not exactly like this but similar, Idle OK, but break up at speed. There was a broken spring in the spark advance. I took of the point cover and, hmmmmmmm, where did this little piece of spring come from??

Can't say as if that fixed the problem as I have to locate a spark advance mechanism or maybe some springs.
 
I am having trouble not exactly like this but similar, Idle OK, but break up at speed. There was a broken spring in the spark advance. I took of the point cover and, hmmmmmmm, where did this little piece of spring come from??

Can't say as if that fixed the problem as I have to locate a spark advance mechanism or maybe some springs.
 
Johnny,

The spark advance was the problem on my bike, now it runs great. You might want to double check yours. It is located directly behind the points breaker plate. If you remove this plate to get at the spark advance BE SURE TO MARK EXACTLY WHERE IT IS BY MAKING A MARK ON THE PLATE AND ON THE HEAD SO YOU CAN LINE IT BACK UP or you will have to redo the timing all over again. Read the above again! I speak from experience.....

Check that the springs are there, and that the unit is not frozen up.

Just a thought.

Jack
 
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