cl100 carburetor?

venicedan

venicedan

"get busy living or get busy dying" sr
so im in the process of rebuilding a 72 honda cl100. im almost done with but cant get it tuned. when i start it, it runs great at idol, but when i give it alot of gas at higher rpms, it starts to choke out, backfire and smoke. i think its the carburetor. everyone i talk to says it sounds like its getting to much gas. ive messed with the slide stop and air mixture screw until im blue in the face. ive adjusted the ignition timing a million times and have adjusted the float. ive had the carburetor apart and cleaned probably 5 times. any help here would be much appriciate.
dan
 
Have the valves been adjusted properly as well? And have you tried re-jetting the main?
 
If carb was 'cleaned properly' you only do it once.
What colour is spark plug?
You probably adjusted float level wrong and fuel level is too high.
Tilt carb from completely inverted until tang on float just contacts shut off valve.
The main jet is tight in emulsion tube?
Do you have flywheel magneto or points under cover on left side of cylinder head?
 
boy i hate being a newb... but im getting it!! i went and bought feeler guages this morning and did the valve adjustment. what a difference that made. wholly crap! runs like a top! thanks guys for the help. it seemed like a fuel issue for sure, but ill be damned!
 
crazypj said:
If carb was 'cleaned properly' you only do it once.
What colour is spark plug?
You probably adjusted float level wrong and fuel level is too high.
Tilt carb from completely inverted until tang on float just contacts shut off valve.
The main jet is tight in emulsion tube?
Do you have flywheel magneto or points under cover on left side of cylinder head?
Click to expand...


false alarm, still runs crappy. i have points, im to play with the float again.
 
well... still no luck. here is what ive done so far.
adjusted valves, adjusted float again to 24mm, gapped the point again, played with advancing and retarding the ignition and new spark plug, i also went through the carb again to make sure everything was clean and tight. so im about to pull my hair out. i do have a carb kit on its way, should be here monday. so ill try that and see what happens. here is what i think could still be my problem.
carbs - kit on its way
timing - still cant figure out how to make sure its right (anyone know of a good how to video or something?)
cam chain - ?... so if i was off a tooth either way, would it give it these symptoms? im 99.99% sure i got it right, but..... you just never know

any help or thoughts would be greatly appriciated!
 
I'm assuming it's a dry black compared to wet. That means that most likely you are running rich - either from too much gas, too little air, or a very weak spark (assuming the valves, float, etc are set correctly).

Check the air filter is clean, choke is working properly, battery is holding a good charge, and that you are getting a big blue spark.
 
Big Rich said:
I'm assuming it's a dry black compared to wet. That means that most likely you are running rich - either from too much gas, too little air, or a very weak spark (assuming the valves, float, etc are set correctly).

Check the air filter is clean, choke is working properly, battery is holding a good charge, and that you are getting a big blue spark.
Click to expand...

hey thanks for your help rich! last night i was fiddling around with stuff, then the bike quit starting. i gave up and went to bed. this morning i got up went out and checked the spark and there is none. the battery charged all night and has a full charge. so maybe it was a week spark the whole time. heres crossing fingers hoping thats it.
 
Big Rich said:
I'm assuming it's a dry black compared to wet. That means that most likely you are running rich - either from too much gas, too little air, or a very weak spark (assuming the valves, float, etc are set correctly).

Check the air filter is clean, choke is working properly, battery is holding a good charge, and that you are getting a big blue spark.
Click to expand...

so i changed the point gap, thats why i had no spark..... got that gapped right.
so here is where im at right now... i pulled the air cleaner completely off and it runs like a champ now!! but when i put it back on it runs like chit and puffs out smoke at higher rpms. so... its getting to much fuel. right? so i have a rebuild kit coming, should have it monday. ill try those new parts. currently the main jet is 105 (was already in there) and the book calls for a 110. so the jet cant be the problem right? seems like i could just put a pod on it and call it a day. but i think even then when its wound up at a high rpm, it still smokes just a tad. i need to just fix the problem. maybe i need to adjust the float again. one more thing, when it started running great, i had sprayed some starting fluid in there ( just a touch, i know that chit is the devil) and it seemed to just come alive after that. im so confused. haha
hey thanks for you patients rich. im so happy to have made some progress.
 
How much fuel and was the filter on?

Sounds to me like your filter is restricting flow at higher rpm's. But if the carb is back firing (not just "spitting") then it's a lean condition.
 
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