Carburetor Question...But About A Honda!!!

Hey...I have 2 Kawasakis, and have found this forum helpful for those, so I'm hoping for some advice about this crazy Honda.

It's a 1980 CM 400A Hondamatic twin. The bike is in very good shape except for the fact that it will not run without starter fluid. I pulled the carbs out and replaced all of the parts with a Re-build kit that I bought online, then I reinstalled it and it still won't run unless I'm constantly spraying starter fluid into the air intake. It is getting gas into the float bowls, because I have taken the carbs off about a dozen times and cleaned, dumped and blown them out.

Here's the other fun thing, each time I spray the starting fluid repeatedly into the airbox, the darn thing catches fire, partially from the ether and partially from the gas that flows into the air box.

Any ideas??

MooseVegas
1.) 1993 KZ-100p
2.) 1983 KZ-650sr
3.) 1980 Honda GL-1100
4.) 1980 Honda CX-500
5.) 1980 Honda CM-400A
6.) 1986 Honda VT-1100 Shadow
7.) 1972 Honda CL-350 Scrambler
8.) 1983 Yamaha Virago 920
9.) 1969 Bridgestone 350 GTR
10.) 1985 Honda XR-80

pull carbs apart and soak them overnight;)

Sounds like fun...I have a drum of Berryman Carb Dip and a big bag of ruffles...lets see what happens

I have a 78 CB400A. Daughter's actually. It's a great bike.

If your compression is good, your spark is good, and the carbs are clean, she'll run great too.

For carbs, you'll have to disassemble and carefully clean all jets and tubes. IIRC there is an exploded diagram in the manual. Mine is up in Canton, 42 miles from the house, or I'd take a look.

Especially make sure you get the main jet and mai jet emulsiion tubes clean including the small holes o the sides of the emulsion tube.

I just bought a second CB400A engine. Gonna use it on a chopper. Very clean to use pedal for gas, pedal for rear brake, hand lever for 1-2 selector, and only the front brake on the bar. Need to find carbs, kicker, and shift lever for it. They'll run OK without the battery if you keep the revs up to about 1100 or shut the headlamp off when idling.

-Duck

Also make sure your tank is clean and that you have a in line filter. If the carbs are clean as you say then it should run without starter fluid. It must be picking up crap from the tank and clogging the jets.

moosevegas wrote:

Hey...I have 2 Kawasakis, and have found this forum helpful for those, so I'm hoping for some advice about this crazy Honda.

It's a 1980 CM 400A Hondamatic twin. The bike is in very good shape except for the fact that it will not run without starter fluid. I pulled the carbs out and replaced all of the parts with a Re-build kit that I bought online, then I reinstalled it and it still won't run unless I'm constantly spraying starter fluid into the air intake. It is getting gas into the float bowls, because I have taken the carbs off about a dozen times and cleaned, dumped and blown them out.

Here's the other fun thing, each time I spray the starting fluid repeatedly into the airbox, the darn thing catches fire, partially from the ether and partially from the gas that flows into the air box.

Any ideas??

MooseVegas
1.) 1993 KZ-100p
2.) 1983 KZ-650sr
3.) 1980 Honda GL-1100
4.) 1980 Honda CX-500
5.) 1980 Honda CM-400A
6.) 1986 Honda VT-1100 Shadow
7.) 1972 Honda CL-350 Scrambler
8.) 1983 Yamaha Virago 920
9.) 1969 Bridgestone 350 GTR
10.) 1985 Honda XR-80

The fact that you are having a start issue tells me the low speed circuit is gummed up. Heres the deal. With the carb bowl off look into the two small openings looking up at you. One is the low speed the other the high speed. You will need a #80 hobby drill to clean out this small orifice. Soaking overnight without the use of an ultrasonic (vibrating) bath will not work. Mount the #80 drill by into one of those WD40 red straws and slowly ream out the low speed circuit. It is commonly overlooked but will cure your problem.

Good Luck

Hello Vipex,

I tried cleaning those ports this morning. There were actually 3, but one set was covered with a rubber plug, so I thought, what the hell, and pulled the plugs out as well.

Long story short, no luck, it will still run with starter fluid, but as soon as it burns off, the bike quits.

What's next?

MooseVegas

Update... I just went out and tried again. I shot some starter fluid into the air box, hit the button, and boom, it exploded, sending the air box cap about 8 feet in the air. Could this, and the fact that the airbox gets gas into it be a sign that something is backwards??

moosevegas wrote:

I have a drum of Berryman Carb Dip and a big bag of ruffles...

:S No, no, no, it's not that kind of dip!:pinch:

Update... I just went out and tried again. I shot some starter fluid into the air box, hit the button, and boom, it exploded, sending the air box cap about 8 feet in the air. Could this, and the fact that the airbox gets gas into it be a sign that something is backwards??

LOL!! No, it means that starter fluid is VERY DANGEROUS! It's really only meant to be used when the air is so cold gasoline has a hard time vaporizing. I meant to jump in here before, but I'm ADD and went riding bicycles with my friends after school. OK, their imaginary, but they're friends. Now, about this-
First off, DON'T USE STARTER FLUID. Yes, I yelled. Be nice to the machinery. Use aerosal carb cleaner. Much closer to gas in volatility and octane than starting fluid. So, if it will run on carb cleaner, you have a carburator problem.

Post edited by: pstrbrc, at: 2007/02/22 16:17