Topic: cb500 starting issues: Solved. I'm a moron, there I said it

[Spanner 1]

Ans; The meaning of Life 

[Danno]

thanks spanner I am glad he listened to your post I told him that 14 posts ago

[Spanner 1]

Agreed..... Danno post #34 got it about the coils bass ackwards.. good 'on ya. OP should have looked at it then

[spot45]

Spanner you told him a while ago to check the points.  If the carbs and coils are good, then the only thing left is to check the points.   Myself and a few other guys just reinforced what you said.   IT is so easy to forget that when trying to diagnose a problem things have to be done in order.  Rule out one thing and then move onto the next.

[andrewk]

90 percent of carburetor problems are electrical.

I think that at times it is easy to get lost in the diagnostic process when there is more than one variable in play.  It is good practice to always double check the fundamentals.

[davis96]

thanks spanner I am glad he listened to your post I told him that 14 posts ago

I know I know guys i feel like a dick now, I'm sorry. I did read that post a while back, I even went out and checked.. But since both of my coils has blue wires I knew one of them was going to look wrong, I just glanced too quickly.

The good news is the timing and points were right, and today I got her started right up, despite pissing gas all over the pavement. Here's the video:
http://s1141.photobucket.com/albums/n593/cheezycube/?action=view&current=8ef31233.mp4

To do now: fix overflowing bowls, bleed the brakes, sort out this crappy cb500 clutch, and ride

[seanbarney41]

thanks spanner I am glad he listened to your post I told him that 14 posts ago

To do now: fix overflowing bowls, bleed the brakes, sort out this crappy cb500 clutch, and ride

...and pull that black tape off your headlight...and whack your float bowls with a screwdriver handle so they stop leaking (almost always necessary after any carb disturbance)

[Dimitri13]

Yep, kick those carbs a few times. But leave the tape on your headlight, I like it

[davis96]

thanks spanner I am glad he listened to your post I told him that 14 posts ago

To do now: fix overflowing bowls, bleed the brakes, sort out this crappy cb500 clutch, and ride

...and pull that black tape off your headlight...and whack your float bowls with a screwdriver handle so they stop leaking (almost always necessary after any carb disturbance)

Warning: all style suggestions are taken with a grain of salt

Yep, kick those carbs a few times. But leave the tape on your headlight, I like it

Unfortunately, tapping the bowls had no effect....

So my biggest issue now that is keeping me from riding is the damned clutch.

[spot45]

The clutch problem is easy to fix.  80% of the time the problem with the clutch is that it is out of adjustment.  I am saying this because I have put a lot of miles on one of those bikes, and I did have some clutch problems, but once I got the clutch adjusted right, not a single problem with shifting.   The other 20% it is either worn plates or shot adjuster.

[Scott S]

 Had the bike sat for a while before you got it? I had some clutch issues with my '71, but I was resurrecting it from a 28 year slumber. I cleaned all the old goo out of the pushrod actuator, found a broken clutch pushrod and had to pull the basket and separate all the discs by hand. They were very easy to pull apart and spec'd out fine, but after reassembly it worked!
 I found the broken pushrod after putting many miles on the bike. That helped even more, as did a genuine Honda clutch cable.

 As to the gas, it's one of two things: a sticking float or worn out needle/seat valve.

[72500john]

glad to hear it run!! the clutch is a bit of a pain but with patence it will work great. as far as you having fuel dumping out on the ground, consider this. i have seen you have been into the carbs a few times and set the float level. this one got me too, if it is the case. the float level should be set with the arm on the float "just touching the needle valve". not depressing it. i made myself a float gauge out of metal set to the height and it made the job alot easier. sorry no pic of it..it is hopelessly lost in my workshop!

[davis96]

glad to hear it run!! the clutch is a bit of a pain but with patence it will work great. as far as you having fuel dumping out on the ground, consider this. i have seen you have been into the carbs a few times and set the float level. this one got me too, if it is the case. the float level should be set with the arm on the float "just touching the needle valve". not depressing it. i made myself a float gauge out of metal set to the height and it made the job alot easier. sorry no pic of it..it is hopelessly lost in my workshop!

Good point, and one which has gotten me in the past with my other sohc4.. But as soon as they overflowed this time, I made sure to check the float height just as the float touches the pin. Oh and now that you mention it, I actually made a float measuring tool for that very reason when I was double checking heights:

[davis96]

Had the bike sat for a while before you got it? I had some clutch issues with my '71, but I was resurrecting it from a 28 year slumber. I cleaned all the old goo out of the pushrod actuator, found a broken clutch pushrod and had to pull the basket and separate all the discs by hand. They were very easy to pull apart and spec'd out fine, but after reassembly it worked!
 I found the broken pushrod after putting many miles on the bike. That helped even more, as did a genuine Honda clutch cable.

 As to the gas, it's one of two things: a sticking float or worn out needle/seat valve.

I replaced my pushrod and disassembled/reassembled the clutch a while back, but it didnt seem to help.

As for the gas, it is def not sticking floats, but probably is needle/seat. I've done everything I could as far as polishing the needles and seats etc etc.. and I can't find a supplier to replace them (at least not for a reasonable price. David Silver wants $19 per carb)

[72500john]

try this trick..get some fine valve lapping compound and lapp the valves to the seats. has worked good for me on many 3000 psi hydraulic flared connections. of course do it removed from the carb. but i dont have to tell you that.

[davis96]

try this trick..get some fine valve lapping compound and lapp the valves to the seats. has worked good for me on many 3000 psi hydraulic flared connections. of course do it removed from the carb. but i dont have to tell you that.

I actually did this already, except I used toothpast instead of lapping compound, which ought to have the same effect on the soft brass seat. The weirdest thing is that when I had the carbs off, I was able to set them upright on my carb stand

hooked up to the tank, plugged one of the outlets on the petcock, so that gas was only going to 2 of the carbs, then plugged the fuel inlet of one of those 2, so that now gas was only getting to 1 carb. This way I could isolate 1 carb at a time. Then, with the bowl removed, I pushed up on the float lightly while gas was flowing, just to be sure that the valve was even capable of sealing at all... and it did seal! So I thought problem solved, but as soon as I put the bowl back on and tried it, leaks again!

My only theory now is that the tiny little tab on the float which stops it from falling too far
(this little guy):

is getting caught on the post... maybe I can put something rubber over it so it doesnt want to stick on the post.

[72500john]

seems you are doing a fine job on this bike and not a dumd a**. but try brushing your teeth with valve lapping compound instead of tooth paste. it is a bit more abbrasive.

[andrewk]

It's more abrasive but I would think it unnecessary, given the hardness of the seat and needle.

I would lean more towards the carbs leaking from the o-rings around the seat assembly, especially considering that he's working with all new parts, and he's already polished the seats with something aggressive enough to polish brass.

[andrewk]

Oh, I see that the parts aren't new- didn't see that before.  What did you replace the o-rings that seal the seat assembly with?

[davis96]

Oh, I see that the parts aren't new- didn't see that before.  What did you replace the o-rings that seal the seat assembly with?

I replaced them with o-rings. Not Honda pieces, and kind of a tight fit, but from my experiments I know for a fact that the o-rings do not leak.

[davis96]

I really wish someone would manufacture transparent float bowls for these bikes, a la Malossi: