[atownbrg]

1981 Honda CM400a. Whats the best way to remove the carburetors on these bikes? I'm always concerned that the airbox to carb boots may tear the get so mangled about. I have unbolted the airbox, to allow an extra 1/4" of wiggle room but it really doesn't provide that much more help. How does everyone else make this an easier job? I consider it a PITA, have done it twice. BUT I have to go back in to double check my carb rebuild and am not looking forward to R/R again.
So how is this best done?

 

[brokencamchain]

Take a small screwdriver and lift a rubber edge and spray WD 40 inside--it will usually free up the stuck rubber. You can do the same thing with radiator hoses.

 

[J-T]

The issue here is not the hoses sticking to the carbs but rather the lack of space to maneuver in. You can remove the rear wheel and fender allowing the airbox to slide back/out but most folks get the hang of it just doing what you're doing now after the first dozen or so attempts.

 

[I-Ride-A-ホンダ]

"...after the first dozen or so attempts."

HAHAHA

 

[atownbrg]

Ok, Thats what I thought
I was wondering if the rear wheel had to come off to really ease things up. I have to get the hang of it without undoing the airbox too because that rear top bolt with the spacer and nut that fits up in the plastic is BAD!

 

[drydreamer]

Yeh, i always hope that one shears clean off, much less of a pita. With the air box off its much easier to remove the carbs.

Even taking off the air hoses between the air box and the carbs helps, but they are usually rock hard by this age.

With stuff removed and disconnected, try pressing downwards to "peel" the carbs off and out of the rubber head stubs.

If the triangular head steady plate bolts are pre prepped ( the left upper being the bug bare, its a bit too long but if shortened... ) and then removed, along with the air hoses to the air box, the carb head stubs can be undone and the whole assembly slid out to the left.

I tend to refit them this way ( unless the air box is off etc. ) but "align" the carbs and stubs on the bench on a spare head first.

I fit allan bolts to the dash pots and float chambers making in situ carb cleaning very easy. Well worth the slight expense and hassle.

Once you have gone thru the carb experience of fitting new needle valves and just watched the carbs flood, you will know what it means.

 

[Bill H]

If the cm is like the cb I take off the change switch, you dont need to but its to get my big hands in the right side, loosen the clamps on the tubes and slide them to the back as far as they will go. Take the 4 bolts out on the carb insulators , 8MM 6 POINT BOX END on the cb. Pull out the choke lever all the way out so choke arm wont catch on the left boot. Pull the carbs back as far as you can, tilt down as far as you can , and take them to the left half way out , remove the cables , then take them out the rest of the way. Put them back the same way. When you put them back in ,cables on, carbs in place tilt them down towards the front ,put the bottom of the carbs in the boots ,pull back as hard as you can and slide the insulators up into place. This way the boot is on the bottom of the carb and all you have to do is work the tops on. Iv done about a dozen cbs and this is the best way Ive found. Never worked on a cm but they cant be that different.

Bill

 

[atownbrg]

Drydreamer and BillH, excellent detail, thank you!
I'm currently out of town, but going to apply some of these suggestions when I get back!