1980 ct70 won't start

[jsander9]

Just picked this up over the weekend. The tank was rusted and the carb was caked with rust and grime. I tore it apart and cleaned it out, put a new tank on it and fresh gas and a new spark plug. It wouldn't start so I checked spark and I have nothing. What should I check first?? Not real good with electrical issues.....please help!!

[PlanetMinis.com]

[kgmx856]

Is there voltage coming out of the stator? If there is, your coil could be bad or not grounded. Could just need retimed. If its been sitting long enough to rust, the points could be corroded.

[jsander9]

How do i check if voltage is coming out of the stator??

[jsander9]

Cmon guys. Can someone help me out?

[kgmx856]

Use a voltmeter. Black to ground and red to red (depends)

You'll probably have to kick it to see. Simple troubleshooting dude, google it.

[davmo]

Just picked this up over the weekend. The tank was rusted and the carb was caked with rust and grime. I tore it apart and cleaned it out, put a new tank on it and fresh gas and a new spark plug. It wouldn't start so I checked spark and I have nothing. What should I check first?? Not real good with electrical issues.....please help!!

The wiring that comes out of the top of the engine can be checked at the first connector. There are 3 or 4 wires coming out, one should be yellow, that is for your lighting coil. The black one is your ignition coil. Both should put out voltage with the key turned on all the way, while kicking over. If not, you could have a bad ground or bad stator. One real common problem with these older Honda's is a little trick with the battery connector jumper. If you don't have the right battery connector it won't start. Check at the battery connector, if there are two black wires going to the battery (along with the red and blue,) these are the ignition wires. They have to be joined with a jumper to get spark. You can test with a paper clip. If it is not that, check points for corrosion.

[jsander9]

Ok guys i have spark!!! Now on to the next issue......still womt start..... I pulled the flywheel but have never cleaned or adjusted points..... Whats the best way? How do you clean them? Pics or videos anyone?

[davmo]

Ok guys i have spark!!! Now on to the next issue......still womt start..... I pulled the flywheel but have never cleaned or adjusted points..... Whats the best way? How do you clean them? Pics or videos anyone?

Did you figure out why you weren't getting spark? The points can be filed using a small double sided flat file. There are cheap sets of files at Northern tool or harbor freight tool that will do the trick. Pry the points apart and put the file in between the contacts. The object is to clean any corrosion off, while keeping them nice and flat where they touch. As far as the point gap, somewhere around..016", if I remember correctly. The more important thing would be timing. The point gap should just separate as the flywheel hits the "T" mark. You can do this by hooking a continuity tester to the black wire, the other end to a ground, and look for where it dims slightly. That is where the points are opening, and your flywheel should be on the "t" . If not, the little screw that holds your points down should be loosened, and the points adjusted. There is a little slot next to that hold-down screw, where a flat blade screw driver fits and allows you to move the points. When you have a new set of points, that slot lines up with the slot on the stator plate. If you have spark, your points might be in decent enough shape to run the engine. I would look at the carb next for starting issues.

[jsander9]

Ya it's weird I put my new battery in to check out the horn and lights and now I have good spark all of the sudden.....so if I have good spark the points should be in good enough shape where I don't have to clean them??

All of this info is great thanks for the help!!

One more question though I cleaned the carb pretty good but did notice that the pilot jet I was unable to see through the center of it really well. (the little pin hole in the middle) could that prevent the bike from starting?

[davmo]

Ya it's weird I put my new battery in to check out the horn and lights and now I have good spark all of the sudden.....so if I have good spark the points should be in good enough shape where I don't have to clean them??

All of this info is great thanks for the help!!

One more question though I cleaned the carb pretty good but did notice that the pilot jet I was unable to see through the center of it really well. (the little pin hole in the middle) could that prevent the bike from starting?

The reason it started with the battery connected is that little jumper I told you about. It is built into the battery plug. If there is good spark, leave that alone for now. A clogged pilot jet will keep it from starting and idling correctly. The pilot jet can be cleaned with an orifice cleaner (welding store,) or with the small (E) string from a guitar. Bet you will start up with a good carb clean. Make sure you have fresh gas, and that it is getting to the carb bowl, be sure to turn the vent on your gas cap to the "open" position, if it has a switch (some of the later ones don't have it.) If it is the pilot jet, a shot of gas or starter fluid will get the thing to run for a couple seconds. Good luck.

[jsander9]

The reason it started with the battery connected is that little jumper I told you about. It is built into the battery plug. If there is good spark, leave that alone for now. A clogged pilot jet will keep it from starting and idling correctly. The pilot jet can be cleaned with an orifice cleaner (welding store,) or with the small (E) string from a guitar. Bet you will start up with a good carb clean. Make sure you have fresh gas, and that it is getting to the carb bowl, be sure to turn the vent on your gas cap to the "open" position, if it has a switch (some of the later ones don't have it.) If it is the pilot jet, a shot of gas or starter fluid will get the thing to run for a couple seconds. Good luck.

I will give it a shot tomorrow!! Thanks for all of the help!!

[jsander9]

So i bought what you said from the welding store and...........its too clogged i cant get through! I took it to the honda dealer and neither could they. So i need a 38 pilot jet thats a push in not screw in.

Anyone?

[Python]

Some bike shops use ultrasound cleaners for carbs, they usually get all the dirt out that way. I would not recommend poking jets too much with wires etc., they're usually made from really soft brass ... it would be of little use if the jet finally was free but 2 sizes larger than to begin with

[fatcaaat]

Here is how you clean that sucker...take a piece of braided wire and remove the sheathing...now take 2 strands and twist them together. take 3 and twist. make a few singles. now, as you sit in front of the tv mindlessly just pluck away at it. After an episode or two of your favorite show, it will be clean. I just did this on a pilot that was clogged really bad...this is my approach.

[jsander9]

Got it guys!!!!! I let it soak in carb cleaner for a day and used the tool davmo reccomended and after some time its finally free and clear. And guess what??? It started up and runs pretty darn good considering the amount of time it sat before I bought it! Now off to the title bureau to run it in my name and get plates!!!!!

Thanks for everything guys!!!

[SO-FLO]

hey man, i definitely could not have helped your diagnose this sucker... glad you got it running...some people on this forum really know their stuff...i just pretend to


as much as i love my cheapo SSR, i cannot say that it will run just fine after a little "jet cleaning" if it was birthed 32 years ago!!

truly impressive and a statement to Japanese technology...

I have a 1993 Acura Integra DB1 (4 door) thing is solid as ever...used to RIP northern Cali Santa Cruz Mountain roads a few years ago
Also have a 1995 Lexus SC400!! Thing gets sideways everytime it rains here in south florida.... (ok i make it go sideways)

so i like Japanese stuff...glad you got it running man, enjoy..and when you get it tagged, throw soome pics up!!

[davmo]

Got it guys!!!!! I let it soak in carb cleaner for a day and used the tool davmo reccomended and after some time its finally free and clear. And guess what??? It started up and runs pretty darn good considering the amount of time it sat before I bought it! Now off to the title bureau to run it in my name and get plates!!!!!

Thanks for everything guys!!!

Way to go! There is nothing quite as satisfying as making an engine run again. Now you have done it, and you can pass your knowledge to the next guy with this problem. Good job, now do some riding!!!!!!!!