[Scott_Osick]

Hey there, I'm a new member. Just picked up a 1980 CM400T. The bike runs fine except one carburetor is overflowing gas out of the drain. I'm thinking the float is stuck? It was worked on in 2010 and has only seen a few miles since then.

Can I get to it by just dropping the float bowl or will I need to take the Carburetor Off?

 

[doode]

I've had luck dropping the bowl while in the bike.

 

[Scott_Osick]

Thanks. Good to know,it looked like it. That back inside screw won't be much fun though.

 

[longdistancerider]

Do yourself a favor and visit a hardware store from 4x16mm stainless allen head screws plus lock washers. Makes removal so much easier in the future.
You might try draining the offending float bowl first and then close the drain screw. Turn the petcock on while tapping on the float bowl with a screwdriver handle. That could jar the float needle loose and be an easy fix. If that works then you want to add some SeaFoam or Berryman's B12 to the fuel to clean up old fuel deposits

 

[Scott_Osick]

I got the bowl off ok. I did it before the Allen head screw idea. Sounds like a great idea.
I cleaned the float needle good and sprayed everything down with carb cleaner and it started seating.

 

[Scott_Osick]

Took the bike out for a maiden voyage and to get some fresh gas in her. Left side of bike was oily at the gas station and when I got back home I found the crankcase breather tube has come off the air cleaner housing. its too short to go back on and the clamp is missing. Going to get a new hose tomorrow.
Lots of oil though? Is this just because the hose was off or is this much blowby expected? 23000 miles, hopefully the rings are good. Bike performed great on the ride otherwise.

 

[J-T]

Excessive blow by may just be the result of inactivity. I'd replace the hose and ride it keeping an eye on the oil consumption.

 

[Scott_Osick]

Thanks, I've got a new hose on and its much better.

 

[lone]

my 79 mc400t had the same problems had to remove carbs and replace both needle valves mine had keihin carbs large pucksize after a thourough cleaning bike runs greatbut make sure all rubber seals between airbox and carburetors are tightly sealed or it wont run right spent days before i found that that was my midrange running problem and the air filter should be in place or you wont get proper puck action in these carbs
hope this helps

 

[steve9e]

hi jim
great minds think alike ! I have just told another UK buddy to do this simple mod a few weeks ago. Much better than struggling to take of the full assembly.