Frank Angerano

I see you cleaned the tank did you also clean the gas valve at the bottom of the tank ? 

And also make sure the vent at the top of the tank on the gas cap is not blocked. It seems like it’s statving for fuel. What is the air/fuel mixture screw set at ? And has anyone messed around with the main jet needle setting on the carb slide ? 

Hey gator man. Are the new jets oem parts or aftermarket? The jets as far as I know are seated until tight and just a small bit of pressure to make sure they will not come loose. Now as far as adjustment I believe there should be only two screws for adjustment.  1 is the air/fuel mixture screw.  This should be turned until snug and then bring it out about 2 and 1/2 turns and leave it there.  The next one is the idle screw and that should be adjusted once the bike is running.   

The air/fuel screw should be slightly adjusted once the bike is running  maybe a quarter turn more out or in and can be determined after you take a ride and see how she runs. 

Was the carb in bad shape and dirty? 

Also with regard to the jets and  mixture screw were the springs and o ring in place  on the air/fuel screw ?  

I think that the timing is ok based on that pic. 

I would really break the carburetor down and clean it good. It has to soak and use a fine piece of wire to clean the jets out.  A piece of a bicycle brake cable works well in the jets. 

Have some air ready to blow out each jet/passageway you clean to make sure the path is open in the carb.

A small can of that air people use for cleaning keyboards is great. 

A lot of people say they cleaned the carb good only to go back and do it again so make sure you do it right the first time. 

The air fuel mixture should be 2-3/4 maybe 2-1/2 turns out from a snug position. 

I think if you start there and see how the bike runs would be a good way to go with a fresh spark plug.  Also lastly make sure the tank is clean and the shutoff valve is clean.  

Wow. Everyone is all over the place on this. 

Great looking bike awesome find lucky you! 

The cdi is a working or non working component.  So the fact that it fires up I would say it’s good.  

Now since you have all the plastics off and everything is exposed I would take your time and unplug each plug one at a time and clean and add electrical lube and reconnect. 

A good eye glass screwdriver allows you to get in and scrape clean the contacts of all the plugs.

after that go through all the wires that are attached with a bolt or screw, grounds, battery connectors and the starter relay .  It’s very possbale that the starter relay is no good and a much cheaper part to replace. Keep in mind the electrical system is big! That means the coil wires, ignition, handlebar controls, regulator etc. do it in sections and move on to the next section.

After all this is done if it still does the same thing it hasn’t cost a penny before you start guessing and buying parts and all bad connections are ruled out. 

Put a fresh battery in that baby and see what you got.

Lastly is I’ve had a bad cdi box and one way that it will not perform is if it has moisture inside. Simple stupid way to get that out is to put it in the oven for 10 min on 250! Make sure the oven is on 250 before you put it in and no more then 10 min. Take it out and cool off and try it. 

Good luck and keep up posted.

You get what you pay for. A cheap pair would have prob not welded well or held up well. Would have been cool If the part had the vice grip name on it where you can see it.  

Nice work! 

That’s a great design. Love the vice grip part. Did you weld that together while that shifter was still attached  to the bike ?  Usuallly bad for the shifter seal and bad for the electrical system. 

There are parts ! I have a guy in PA he is great.  He has so many parts etc. if you need anything I will shoot you his info. He ships all over!

So I would first start off by checking for spark. If you don’t know how to do this it’s simple.  Take the spark plug out and plug it into the spark plug wire and put the bottom of the spark plug against the engine so it’s touching a good metal part of the head  and crank the engine. There should be a good clean blue/orange spark at the plug.  If not try the old cdi and repeat. Make sure the run switch is on.  If you have spark then great it will be a fuel issue.   Try this and get back to us.  

Worked out perfect! Bike runs like new.  This happenes to be on of the most powerful bikes I own.  It’s amazing how theses parts were  still available.  

But in the end 100% worth it and a ton of fun ripping it apart and putting back together.  

Thanks for asking!

It’s shows the TDC and how it’s done. 

It looks good. Check this out maybe it will help. 

Cam lobes facing down, sprocket marks parallel to the head cover and the sprocket should have a small hole on the top side about 1 o’clock ish. 

So let’s back up for one second and recap.

Did you pull the head off of so why?

Did the bike run while you own it?

reason I’m asking is in my experience I’ve missed things during a rebuild back in the day and had to go back to see where I failed.  

You are missing something. I looked at the manual and can see that there is only one timing mark that’s labeled “c” ? 

The  lobes state they should be facing downward and there is a small hole on tye cam sprocket that should be on top ? 

I would go back double check that. If all looks right then I would look at tye triggger cool maybe it’s loose ? 

Can you post a few pics of the timing marks you see on tye engine as well as the top end cam and sprocket ? 

It’s most likely 180 deg out of time. It’s very easy to make this mistake. 

There are also a few different marks on the flywheel. Make sure that you have the correct mark and make suite it’s on the compression stroke when aligning with the cam. 

Aside from the few things listed above the only other things I can think of is the timing chain is jumping off of the sprockets ? Or the pick up coil is loose delivering the spark at the wrong time.  

Welcome back Allen. It honestly sounds like the engine has seized. I would take the head off exposing the piston and cylinder to see if there is any damage inside the cylinder walls. And maybe go further into this by taking the cylinder off completely. 

But prior to any of that make sure your not missing something else like the starter bearing or in the stator coil area   

Did you drain the oil? 

I have the same bike and it’s reliable and tough. But if there was no or low oil well that’s that! 

Hopfully you will find out and keep us posted. I’ve been a little busy since I opened up my own company but will try to check in from time to time. 

Goos luck. 

There are only a few reasons for that diaphragm to not open.  One being there is a small hole in the actual diaphragm or it’s not seated properly. Two the air flow into the carburetor is restricted at the air filter intake. Three the neede at the bottom of the diaphragm is bent or not sliding in and out of the main jet properly. Four is the carburetor has gotten something inside the main vacuum port or oraface that allows vaccume to pull that diaphragm open “up”. 

The carburetor works on a vaccume system. When you hit the throttle it’s connected to a butterfly damper. The butterfly opens allowing air to be sucked into the carburetor which in turn has a small vacuum port that goes to the top of the carburetor that sucks the diaphragm up hence lifting the needle up allowing more fuel and air to mix and enter the engine. If that vaccume system is blocked or any one of the above listed items are compromised you will have a problem. I would bet the diaphragm is not seated right or has a hole in it. 

I attached a link for your use to see how this works. It’s worth a watch. You will have a clear understanding of how it works. 

Good luck. 

It looks like a Yamaha based on the way the engine sits but not sure. Have you been able to locate the vin number on the frame ? 

 Have you looked on eBay for a used one ? I’ve picked up an oem carb before from eBay in good shape put a rebuild kit in it and for $100 I had a very good oem carb.

im assuming yours is beyond repair or the bike cane without one ?

Very good. Should be a sold engine after that. 

Good luck and keep us posted. 

You are missing something, did you wire brush the top of the piston and the head for carbon build up to make sure there aren’t any pinholes or cracks? I would also check the head where the gasket sits to make sure it’s not warped. And lastly the rings could be bad even though they look ok. I would think it’s just a piston and ring replacement job. 

There could be a hairline crack in the cylinder jug or head  but that would probably have shown up with a dark spot or hearing air coming from it. 

I would put a new gasket kit and piston and rings and see where you are at.  

Ive heard of the 50cc engines losing compression from the crank case bearing seals but not on the 80.   

Welcome to Quadcrazy. From your description it sounds like you heard a noise and then it shut off?  Is the bike in neutral ? It’s possable that the engine is seized up.  I would take the spark plug out and try to pull start it to see if the engine turns over.  Then drain the oil if there is any oil in the engine and see if any metal pieces are present.  It’s also possable that something else is locking up the engine causing it not to spin like a blown clutch bearing, maybe something came apart in the stator coil area or transmission. 

Wow that’s a lot of oil.  Prior to breaking it down I think I would give the engine a complete wash down with a can of gunk engine cleaner and make sure you have the location of the leak nailed down. Just to be safe.  

Yes most likely a head gasket but this happens some times bc you loose a valve seal and the head gets oil inside the cylinder and during the compression stroke the gasket blows out. Have you done a compression test? Hopefully not the case here and just a gasket swap. And yes generally easy. Download the manual and get fimillar with the engine as well as YouTube the work. Between that and Quadcrazy member support I think you will have it up and running in no time. 

Post some more pics when you tear into it if you can please. 

Forgot to mention. 

Have you pulled the plug and checked for oil on the spark plug? 

Welcome to Quadcrazy, it appears from the picture that your head gasket is blown and hopefully not a cracked head.  If you reved it as high as you said you did then it’s possable more damage was done like a valve seal but I don’t think so. You may get lucky and just need a new gasket.  I would spray a soapy water solution where the oil was coming out and slowly crank the engine with the spark plug wire off so it does not start. You  should see bubbles if its coming from the head where you see the oil leak.