What do you know about the CX500?

[Cormanus]

There's someone here who's a carburettor specialist isn't there? And, yes, indeed, it's wiredgeorge—see here.

 

[Pterodactyl_imp]

Well...the electrical system didn't fry out when I added a power source....

Engine cranks, but won't turn over. Got a fuel problem in that when I open the fuel valve, gas just pours out of the bottom of the carbs. Tightened up what I believe to be the drain screws, but that didn't really help much. Too hot outside to continue tinkering, but sort of happy that the electrical is not completely shot.

MTC, don't over tighten those drain plugs. The carburettor bowls have a drain tube which runs down the centre of the plugs and drains fuel from the bowl if it is overfull. If a drain tube is split or cracked fuel will flow down the tube if the bowl is not overfull and leak from the plug. Cracks, or splits, in the overflow tubes can be difficult to see so inspect carefully. However, as both your carbs leak it is unlikely to be the cause unless both drain tubes are split or cracked. You will have to pull the carbs to do this inspection.

In your case, as both carbs leak, maybe the float valves are not seating correctly. This could be caused by the float valve and seats being contaminated by crud from the fuel. Try this before pulling the carbs: Turn off the fuel at the fuel tap and open both floatbowl drain screws and drain the fuel from both carbs. As the bowls empty the floats drop and the needles drop away from the seats. When the bowls are empty turn the fuel back on and tap the carbs with a screwdriver handle while the fuel drains through. About 15 seconds or so should be enough. Leave the fuel on and close the drains. With a bit of luck this will have flushed the crud through. Be careful when you do this as a fair amount of fuel will be lying around unless you can catch it. I would hate to see you barbecue yourself. I enjoy your ride reports too much .

However if this fixes the problem it will almost certainly occur again as more contaminant (crud) probably remains in the tank. Best to drain the fuel tank, flushing it with clean fuel to ensure no dirt remains. Fit a fuel filter.

If fuel still leaks after this (the clearing procedure) then you will have to pull the carbs. In which case check the valves and seats are in good condition and the valves are seating correctly with the floats in the full bowl position. Also check the integrity of the drain tubes. If you want to do a thorough job then rebuilding the carbs is not difficult.

Hope this helps.

Cheers

 

[emptysea]

I think it will help, thanks. I will try this tomorrow, I hope. my hope is to get it to sputter...I don't even need it to run at this point. If I can get that far, it think it will be worth investing some time and money onto the project. Thanks for the tips!

 

[Pterodactyl_imp]

If the bike has been sitting for a long time fuel will have evaporated/broken down and a gum like substance will be evident in the tank, fuel lines and carbs. This will need to be removed. Normal carb clean products won't do. Brake cleaning fluid, oven clean, paint thinners and a number of other things are reputed to be effacious.

Cheers and good luck

 

[CA200_imp]

MTC some of the after market carb kits work great, it's not that hard if you just take your time and clean every
little hole you see. http://www.powersportrider.com/cgi-bin/zcatjpg

 

[flynrider]

If the bike has been sitting for a long time fuel will have evaporated/broken down and a gum like substance will be evident in the tank, fuel lines and carbs. This will need to be removed. Normal carb clean products won't do. Brake cleaning fluid, oven clean, paint thinners and a number of other things are reputed to be effacious.

Cheers and good luck

+1 It's important to get all of that stuff out of the fuel system. If you don't, the carbs will clog up soon after they're rebuilt.

It's probably that gunk that is clogging the needle valves and keeping the fuel flowing into the float bowls.

 

[emptysea]

Yeah..gonna drain the entire tank and take a good look at the carbs. Seems like there are plenty of how-to videos out there. Also going to talk to my favorite Honda mechanic to see if he'll look it over and set me up with a punch list of things to do. We'll see. All this cuts into riding time, so I may just see if I can hire out the work or sell it as is.

 

[Cormanus]

ES, pop it into the corner until those cool Chicago days when it's too cold to ride are upon you again.

 

[flynrider]

Yeah..gonna drain the entire tank and take a good look at the carbs. Seems like there are plenty of how-to videos out there. Also going to talk to my favorite Honda mechanic to see if he'll look it over and set me up with a punch list of things to do. We'll see. All this cuts into riding time, so I may just see if I can hire out the work or sell it as is.

The amount of raw labor required to resurrect the average garage queen usually means that the cost to pay someone else to do the work would far exceed what the bike is worth. This is why many shops are reluctant to work on old bikes. I've resurrected a few over the years and it is only cost effective if labor expenses are close to zero.

If money is no object, that's a different story. Last week I posted a pic of my co-workers newly resurrected '77 KZ650. He told me he had a local shop do most of the work and easily spent double what the bike is worth.

 

[Pterodactyl_imp]

Mate, you have the makings of a good bike there. Flynrider makes some good points in his post above. If you are unsure of how to proceed see if you can find a "mentor" with some experience of bike restoration projects. Must be a club of some sort in your area*. As you proceed you will learn a lot about basic mechanical skills, the bike, and, most likely, yourself. I can guarantee that, on completion of the project, you will be proud of your new baby.

Cheers

* maybe enlist the help of your bike mechanic mate.

 

[JustPassinThru_imp]

This all is instructive. I briefly had a GL500...same engine. No problems with the carbs; what got me to sell was it needed a complete brake-system replacement. NO parts...the GL500 was a two-year model that Honda abandoned; different brakes from the CX.

I always wanted to get another one of those Honda V-twins...but this is a reality check. FI is really a miraculous thing; and while it costs more it's cheap in the long run. I should stick with what works...a MODERN bike.

Good luck on yours. It's too bad Honda didn't take development of that model into a more modern machine...

 

[Cormanus]

Well...the electrical system didn't fry out when I added a power source....

Engine cranks, but won't turn over. Got a fuel problem in that when I open the fuel valve, gas just pours out of the bottom of the carbs. Tightened up what I believe to be the drain screws, but that didn't really help much. Too hot outside to continue tinkering, but sort of happy that the electrical is not completely shot.

MTC, don't over tighten those drain plugs. The carburettor bowls have a drain tube which runs down the centre of the plugs and drains fuel from the bowl if it is overfull. If a drain tube is split or cracked fuel will flow down the tube if the bowl is not overfull and leak from the plug. Cracks, or splits, in the overflow tubes can be difficult to see so inspect carefully. However, as both your carbs leak it is unlikely to be the cause unless both drain tubes are split or cracked. You will have to pull the carbs to do this inspection.

In your case, as both carbs leak, maybe the float valves are not seating correctly. This could be caused by the float valve and seats being contaminated by crud from the fuel. Try this before pulling the carbs: Turn off the fuel at the fuel tap and open both floatbowl drain screws and drain the fuel from both carbs. As the bowls empty the floats drop and the needles drop away from the seats. When the bowls are empty turn the fuel back on and tap the carbs with a screwdriver handle while the fuel drains through. About 15 seconds or so should be enough. Leave the fuel on and close the drains. With a bit of luck this will have flushed the crud through. Be careful when you do this as a fair amount of fuel will be lying around unless you can catch it. I would hate to see you barbecue yourself. I enjoy your ride reports too much .

However if this fixes the problem it will almost certainly occur again as more contaminant (crud) probably remains in the tank. Best to drain the fuel tank, flushing it with clean fuel to ensure no dirt remains. Fit a fuel filter.

If fuel still leaks after this (the clearing procedure) then you will have to pull the carbs. In which case check the valves and seats are in good condition and the valves are seating correctly with the floats in the full bowl position. Also check the integrity of the drain tubes. If you want to do a thorough job then rebuilding the carbs is not difficult.

Hope this helps.

Cheers

Try this before pulling the carbs: Turn off the fuel at the fuel tap and open both floatbowl drain screws and drain the fuel from both carbs. As the bowls empty the floats drop and the needles drop away from the seats. When the bowls are empty turn the fuel back on and tap the carbs with a screwdriver handle while the fuel drains through. About 15 seconds or so should be enough. Leave the fuel on and close the drains. With a bit of luck this will have flushed the crud through. Be careful when you do this as a fair amount of fuel will be lying around unless you can catch it. I would hate to see you barbecue yourself. I enjoy your ride reports too much .
It's taken me a while to respond to this as I've had to search for a picture I took once on an island where every young man wants a motorcycle. Mostly they have scooters, but sometimes bikes up to 200ccs.

I came across this sight one day. I've always assumed the bloke was working on the bike and lit a cigarette ...