1980 honda express nc50 wont run

I bought a honda express a week or so ago. The first day it took two hours to start, ran long enough for me to crash it, then wouldn't run again that day. In the following days, I changed the oil and gas and cleaned both of those containers out. I replaced the air intake manifold because it was cracked, as well as the reeds. I cleaned the carburetor 3 times, making sure to get every nook and cranny. The only thing that doesn't, and never has worked is the battery, but I get good spark and my timing points are set correctly. The only thing rusty is the pipe connecting the head to the exhaust. (A few small spots of rust here and there, but nothing major) my throttle control screw was broken, (the part that screws into the carb) but I was able to fix that.

But, even after all this, and reading and re-reading this

http://www.mopedarmy.com/wiki/Honda_Express_Repair

To the point of memorization, I can still not get it to run well or at all. Sometime spraying starter fluid straight into the carb helps, but only for a minute at best. The petcock works on off and reserve but not on.

I am mixing 1 part oil to 50 parts gas in the tank, and using honda two stroke as oil in the oil tank and as the mix. I do this in case I have a faulty oil pump.

I also changed the transmission fluid. But couldn't get the front screw off and had to refill the oil (sae 30) via the drain plug which took two hours! :-(

What am I missing or doing wrong? I have set both the air mixture screw and throttle stop screw to every imaginable combination. I'm at the point of taking it to a shop or selling it.

thanks for the help and advice.

Jon Greene.

Re: 1980 honda express nc50 wont run

So it won't start at all now? Or starts and dies? Will it idle at all?

Has proper compression?

Re: 1980 honda express nc50 wont run

Sounds like a lot going on there. First, you don't need to mix both tanks use one or the other. You can "T" the fuel line to connect both tanks together and pull/plug the oil injector system. No battery = burnt out lights, the front is a sealed beam so a mod/replacement would be in order

Re: 1980 honda express nc50 wont run

Sometimes it starts and dies right away, other times it starts and will run fine until i get ready to.ride after 15 minutes of idleing. But for the most part, it wont start. Compression passes the thumb test. Going to buy a guage, or let the shop check. (edited)

Re: 1980 honda express nc50 wont run

I mix the fuel because im not sure the oil pump is working. Tried to take it out and plug it, but she is really stuck in there. Once i can get it out, i plan on it. I hope i done need a new front end...

Re: 1980 honda express nc50 wont run

I just bought a 1980 express myself, wouldn't run. Did a compression test and it rang a 40 (not good) so i took the head off and it blew a ring and scratched the hell out of the cylinder.

Check the compression, they sell gauges at harbor freight for like $10. If it is a blown head, they got a big bore kit on treatland that im going to install this week.

Re: 1980 honda express nc50 wont run

If it starts at all, it does not have that kind of damage.

Re: 1980 honda express nc50 wont run

It doesn't have that many miles on it (1227ish) so the cylinder should be ok. Ill buy the pressure gauge, and if it's off, take the head off.

Re: 1980 honda express nc50 wont run

Princess Rapunzel /

Jonathan Greene Wrote:

-------------------------------------------------------

> It doesn't have that many miles on it (1227ish) so

> the cylinder should be ok. Ill buy the pressure

> gauge, and if it's off, take the head off.

lolwut

that's more than enough for something in there to wear out. mopeds aren't cars. plus, hey, if I ran straight gas in a brand new tomos, it'd seize. miles don't mean much on mopeds.

Re: 1980 honda express nc50 wont run

yup. i found a hobbit with 1218 miles on it, bearings sounded like rocks in the bottom of the motor. needed new crank, bearings and seals. so mileage means how much fun someone else had till it broke.

as far as the air and throttle screws, those should be set to whatever the manual calls for (i wanna saw air screw is 2 - 2 1/4 turns out) but id double check what honda wants. (edited)

Re: 1980 honda express nc50 wont run

Now it is leaking gas from the little side window on the tank. I think I bought a lemon. Taking it to the shop tomorrow to see how much needs to be fixed. Correction, how little of it works. If it's more than $200 I'll have to take ol' yeller out back and shoot it. (Aka, see if the seller will take it back)

Re: 1980 honda express nc50 wont run

Also another question. The carb float, should it be able to move freely, or should it be a bit tighter with less movement?

Re: 1980 honda express nc50 wont run

Free.

Re: 1980 honda express nc50 wont run

Vegasjetta @Clusterfuck Garage /

Of course it's leaking gas from the side window on the tank, that's the OIL tank and the seal is probably wasted.

Don't bring it back to the seller, just fix what needs to be fixed. I have an extra NC50 tank for sale if you need it.

Don't rush things, do it properly!

If you have to, just replace the cylinder/piston and make sure everything else is in order while the motor is apart. These are not hard to work on.

Do NOT put a bigger kit on it (60cc, 70cc) unless you plan on putting a bigger carb and a pipe, because it won't run right without those.

Re: 1980 honda express nc50 wont run

Yeah, I was just frustrated last night. I bought some epoxy putty to fix the leak, vinegar to de rust the tank, and took some time to realize its a learning process and shouldnt be easy. Im hesitant to remove the head, as i dont have a torque wrench and am not sure if itll need to be re tightened to a certian foot pounds of torque.

Re: 1980 honda express nc50 wont run

You bought a 34 year old bike knowing it needed work and now it's a lemon because you can't fix it? If you read the manual "to the point of memorization" why would you put gas in the oil tank and not realize a float has to move freely? And you actually expect the previous owner to take it back after you wrecked it?

Really?

Re: 1980 honda express nc50 wont run

Take the head off. The bolts need 10-15 ft lb, or "pretty snug". You will need a new base gasket if the cylinder breaks free with the bolts out, so be careful not to bump it or anything.

Re: 1980 honda express nc50 wont run

Ok, first off, as i previously stated i was frustrated. It happens. Second, i did not put gas in the oil tank, and if i wrote that i meant to say i put oil in the gas because i wasnt sure if the oil pump was working. Lastly, as for the manual, i meant the repair wiki on this site which says nothing of the float needed to be free. It is best to ask stupid questions, even if you are doing the right thing, than make a mistake.

Thank you for your kind and helpful words.

Re: 1980 honda express nc50 wont run

All floats, no matter what, need to float freely. Friction will hinder their effective operation.

http://www.vintagemopedsforsale.com/pdfs/honda-express-shop-manual-nc50-na50-express-II.pdf

Re: 1980 honda express nc50 wont run

"Now it is leaking gas from the little side window on the tank."

There is no window in the gas tank. That's why he stated that you put gas in the oil tank. You only bought a lemon If the guy told you that it runs perfectly fine and you should have no quarrels.

Yeah, just be patient and don't take what a lot of people say to heart. And you can't claim to have memorized the manual and not realize there is no window in the gas tank. Lol, no offense.

Re: 1980 honda express nc50 wont run

As you are on the left side of the bike, there is a small dime sized window in the gas tank towards the front near the bottom. Google images will show this. If it isnt a window, what is it? There is some type of dime sized gasket on the left side of my honda express' gas tank, and it is leaking gas. I bought something to fix it though, so all is well. :-)

Re: 1980 honda express nc50 wont run

http://jeml.us/image/H3260/9

this is what's is leaking. But I have a solid fix. Thank you everyone for the help and advice. This bad boy will be running within two weeks. (Knock on wood)

saving the removal of the head for the last project, as it seems the most difficult, and would be the moat expensive to fix. Maybe...

I hope the new air intake and reeds aren't causing the problem. They were in better shape than the ones I replaced.

Step one. Fix leak.

Step two. De rust tank.

Step three. New petcock (if needed)

step four. New battery and lights.

Intermediate steps, cleaning carb, engine, etc...

Re: 1980 honda express nc50 wont run

My oil pump is really stuck in, any ideas how to get it out? WD-40? Also when I get it out, should I put oil in the empty space or empty it out?

Re: 1980 honda express nc50 wont run

I use a screwdriver or similar to work it out. The "empty space" is the inside of you anyone cases and your crankshaft, don't put anything in there. A tiny bit of grease on the o-ring and put the pump back.

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