I need help in rebuilding carburetors for my dirt bikes.?

Question

I really need some help in cleaning up the carbs on my two honda 3 wheelers. both of them have the little mikuni carbs, i believe. i've had the carbs apart more times than i can imagine and cleaned, poked and prodded every orifice i could find. blew out everything with compressed air. put them back on the bikes and NOTHING.

this sucks---as some of my friends on the Suzuki RE5 list keep pointing out--if you have air, gas and a spark--the engine HAS to run. i've got air and spark but just can't seem to figure out what i'm doing wrong with the carbs. can anyone recommend a good carb cleaning/tinkering book? i have haynes manuals---no good. what am i missing?

these damn carbs are like so much voodoo to me---after you've had them apart and cleaned and blown out with air over and over and they STILL don't work!

thanks for your input!

noah buddy---you're right, they're the keihin carbs on these little honda 3 wheelers. i think the mikunis are on my suzuki.

Answer 1

best book I've seen is Haynes Motorcycle fuel systems. its about $25.00, cheaper than a half hour labour in just about any bike shop

Answer 2

Seems to me Honda used Keihin carbs on those machines, but that doesn't really matter. Take off the float bowl and remove the smaller jet, it's the pilot jet and is located closer to the end that goes to the engine. While you are there remove the larger jet also. Now go to Wal Mart or an auto parts store and buy a can of Berrymans B12 Chem Tool and soak the jets in it for a night.
Blow them off and look through them or keep soaking them until you can. Use compressed air to blow through the hole in the carb where the pilot jet came out of, make sure you feel the air coming out in the carb throat. This passage MUST be clear. Blow out all other passages then put the carb together and install it. If she starts your in luck, if not you need to look at the valve timing. Those engines were known for the cam gear slipping out of time since the gear is pressed onto the cam. Hope this helps.

Answer 3

You are certain that you have air, spark, and compression and that you are missing fuel? You can check this with a VERY quick shot of ether(starting fluid). If the motor fires, than you have a fuel problem. Is fuel getting to the carb and is the fuel bowl full when you disassemble and clean. If so then you may have a plugged jet. Try removing the jet from the carb and blowing through it by mouth(easier to tell if plugged). If it's clear then check tube in venturi. Keep in mind that these carbs are very small. Any dirt, debris or varnish can plug them. You may need to soak them(submerged) several days in carb cleaner before they are truly clean. Good luck!

Answer 4

Is the gas on? check the reserve valve. Also.....remove supply line and see if gas pumps gas out line check the whole line for kinks/clogs.....be careful to point line away from any heat source including spark plug......if gas is pumping out....re-attach line to carb....check to see if gas is pumping into carb while your turning it over....if you can't do this while attempting to start it;set a paper towel in there and turn it over....it should come out wet....is the spark plug your using have the right gap set?.........your friends are right though....air spark and gas...

Donelson Cycles, Inc.
9851 Saint Charles Rock Rd
Saint Ann, MO 63074-2040
[phone]


Dave Mungenast Motorsports
5935 S Lindbergh Blvd
Saint Louis, MO 63123-7039
[phone]


Chesterfield Valley Power Sports
17501 N Outer Forty Dr
Chesterfield, MO 63005
[phone]

Bob Schultz Motors, Inc.
3830 W Clay St
Saint Charles, MO 63301-4417
[phone]

Belleville Honda
2100 N Belt W
Belleville, IL 62226-5903
[phone]

If your in Missouri...(guessing from your yahoo nickname)....here are some dealers in your area....call them and ask if they have the repair manual you are looking for.

Answer 5

thankfully I also have a Suzuki 125cc airborne dirt and dust bike and as quickly as apon time I even have had that comparable situation after leaving my airborne dirt and dust bike up for better than a month that i comprehend of. the situation is particularly what each physique else is saying....the waft valve needle is caught and must be wiped sparkling/ mounted if achieveable.