1979 CM400T

C

colpumpkinnuts

Banned from public transportation
Picked up a 1979 Honda CM400T about a month ago. When I bought it I didn't think that I would be doing much to it. That didn't last long. I didn't take any pictures of it before I started working on it but it was pretty much stock exept it had a 2 into 1 exhaust with a nasty leak which made it VERY load, K&N filters and flat black body work. When I took the first pictures I had put on a clubman handlebar, removed the grab bar, reduced the width of the front turn signals and painted them, replaced the old, sticking throttle cables and removed the passenger foot pegs. I've had some clearance issues since I installed the clubman bars. The brake fluid resevoir is hitting the right turn signal and the brake hose and throttle cables are too long. Oh well, so long as it runs. I've been having issues with photo bucket so I'm trying image shack. Hope this works
 
It looks like my post worked. I'l try to remember what I've done to the bike since I took the earlier photos. the biggest thing was replacing the stock teardrop tank with a CM400E tank. I got it off ebay for cheap with a large dent in it. I fixed the dent as best I could and pounded knee dents in it. I did my best smoothing them with bondo but I'm not happy with the results. When I tried mounting the tank I found I needed to shorten the front mounting posts and put in dents to provide clearance for the clubman bars. I'm not happy with the paint, still needs a long way to go but I think I'll save it for the winter. The goal is to keep the bike running while I work on it.


 
Well, I ran into a problem with bike today. What used to be an almost decent running bike turned into a mess of problems after I rebuilt the carburetors 1-2 weeks ago. Today I started the bike up without a problem, then it died and started pissing gas out of the overflow tubes. This is the second time this has happened but it is the first time the bike would not run because of it. I took the carbs off thinking the floats might be sticking, they seem to be fine and they are at the correct level. Does anybody have any ideas?

Figuring that this might take a while to fix I decided to take the exhaust off and clean it up. One of the nuts was siezed on the exhaust studs and I ended up removing the whole thing. I had to clamp the stud in a vise to get the nut off. The nut that was mounted to the cheap muffler that's on there broke so I had it wired up with a coat hanger for a while. Time to fix that. I cleaned up the exhaust flanges with a wire brush and I'm plannning to paint the exhaust pipes because they're rusting.

 
I got some paint for the exhaust pipes today, as soon as it stops raining I'll spray them. I started fabricating a cage for the new battery placement. The regulator/rectifier will be attached to the bottom of the cage and the other electronics will be moved as well. I still haven't come up with any ideas as to why the carburetors are pissing gas.
 
I've finished the new battery mount and I have the electronics hidden underneath the new seat. The mounting brackets for the seat are complete and mounted and I've started working on a new mount for the tailight. I've drilled holes in the underside of the seat and I've filled them with epoxy. The plan is to tap the holes so I have a solid mount for the tail lights. Hopefully tomorrow I'll be able to finish painting the exhaust, we're supposed to have some good weather. I've already cut and trimmed the foam for the new seat, now I to cover it and mount it.


The seat brackets:
 
This is the second build I have come across on this site where the battery is mounted on its side. I was always told this was a bad idea, that batteries should always be upright to avoid issues with the acid. How does that work with the drain tube that each battery has? Are there any concerns about acid leakage from the caps? Not passing judgment, just curious.
 
The batteries that you see laying down are sealed AGM (absorbed glass mat) type batteries. The acid is absorbed into the matting and has a very remote chance of ever leaking. You cannot lay down the old style lead acid batteris.
 
MBS said:
This is the second build I have come across on this site where the battery is mounted on its side. I was always told this was a bad idea, that batteries should always be upright to avoid issues with the acid. How does that work with the drain tube that each battery has? Are there any concerns about acid leakage from the caps? Not passing judgment, just curious.
Click to expand...

You have to use a battery that can be mounted on its side such as a sealed(some types) and or gel cell type.
Just because a battery is a sealed type though doesn't automatically mean you can mount it on it's side. The manufacturer can inform you if their product can be mounted in any position other than straight up.

Most Gel Cell batteries for that matter can be mounted upside down if you chose.

You can of course not do this with regular non-sealed lead acid batteries that build up gasses/pressure and need to vent and will leak acid if you place them on their sides. Also placing them on their sides may exposes the plates inside(stick out of the water/acid solution) and could cause them to corrode,thus degrading their performance.
 
I bought this battery specifically so I could mount it on its side. It's sealed and doesn't require filling with acid and it doesn't have a drain tube.
 
Made quite a bit of progress yesterday. Got the exhaust reassembled, sealed and ready for paint. Reinstalled the freshly painted rear brake lever and center stand. Also got the taillight mounts on the new seat tapped for 10-32 machine screws. I would have used metric hardware for it but I don't any metric taps available at the moment.
 
I did the same with my battery. Allows for a minimal bum stop if you so require. Mine was a bit expensive. How many clams did you have to shell up? (always looking for a better deal).
 
I think I paid $57 dollars from www.batterystuff.com. Shipping was free. The battery's working out great so far, it came charged. All I had to do was pull it out of the box and hook it up. My new seat has a huge hump in the back, a bit bigger than I had wanted. No need to put anything in it yet. I'm still able to keep the tool kit in it's stock location.
 
colpumpkinnuts said:
I still haven't come up with any ideas as to why the carburetors are pissing gas.
Click to expand...

I recently had a similar problem after rebuilding the carbs on my CL450. Thought the float may be stuck so I whacked it. That fixed it. Then that carb would run out of gas. Whack it again, and then it would flood. >:(

Turns out the the bowl gasket protruded into the bowl just enough so that the float just barely touched it. So it would ocassionally get stuck up or down. I trimmed the gasket with an exacto knife to get more clearance and haven't had a problem since.
 
Progress! I think (hope) I found my carb problem. After taking the carbs apart (again) I looked very closely at the float valves, thinking they were damaged. I found that the new brake line I installed 2 weeks ago was deteriorating and little bits of rubber were getting into the carbs. Several of these small bits were stuck in the float valves preventing them from shutting completely (I think.) I've cleaned the cabs out and I'll be reinstalling them with different fuel line and a new filter later today. I've also painted and reistalled the exhaust. I ran into a hiccup with the tailight mounts, but nothing that will take very long to fix. If you look closely at the pic you can see one of the pieces of fuel line in the valve
 
It runs! I forgot to get new fuel line and a filter when I got out of class today so I hooked up the carbs with a piece of vinyl tubing I had. It seems to be running fine. This was the first ride I've taken on the new seat. It seems to be pretty comfortable despite not having a cushion on it yet.
 
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