my old new bike

[Nismo3240]

I just got a 1980 yz125 from my father in law. Got it home, put some fresh fuel in it and a new plug, took a while to fire up cause its been sitting for a long time, but when it did it didnt like to rev up much, maybe cause it wasnt running for long, but I did notice an exhaust leak at the manifold, I took off the exhaust pipe and there wasnt a seal or anything there. So I am thinking I need a new gasket. Ive heard a little bit about using silicone or exhaust tape, would this work on this bike better then a new seal, and will it possibly solve the sputter when I rev it up?

 

[Tom68]

Regular silastic works perfect with bolt up pipes 2 and 4 stroke. Should work if your springs are tight enough.

 

[89RM]

Don't forget to clean the carb. I wouldnt do a bandaid fix for the exhaust leak, just go order a new gasket and springs, it won't be that expensive.

 

[Nismo3240]

thanks. so would a little brake clean thru the carb?

 

[rmc_olderthandirt]

but when it did it didnt like to rev up much, maybe cause it wasnt running for long, but I did notice an exhaust leak at the manifold,

There should be a small "flange" that bolts to the cylinder at the exhaust port. This flange will have a gasket underneath it.

The pipe slips over the flange and is held in place with one or more springs. There should be an "O-ring" type seal inside the pipe where it slips over the flange. Often times this O-ring is hard to see from all the crud that has deposited on it.

It is not unusual for the O-ring seal to leak, and I doubt that it is your problem but I do recommend replacing it. I do not recommend any "band-aid" type patches.

Did you ride the bike, or just try reving it up in the garage?

I would recommend taking it out and getting it good and warmed up before you make any hasty decisions. It wouldn't surprise me if the bottom end is a bit gunked up from sitting a long time and getting it up to operating temperature may clean things out.

It is also very possible that the carburetor needs to be cleaned. The only proper way to do that is to take the carburetor apart and soak it in a very strong solvent. You MUST remove all the jets in order to get the solvent into where it needs to go and you must remove the float valve so that the solvent doesn't destroy it. Let is soak overnight, rinse with water, blow out with compressed air and reassemble.

You can still buy OEM parts for this bike so I highly recommend buying a set of carburetor gaskets and new float valve. If you don't need them now you will eventually. Take inventory of what else the bike needs and order it all at once, it will save shipping and handling charges.

Things to look for:
Chain guide (plastic piece on swing arm, guides chain onto rear sprocket).
Chain rollers, on frame near pivot point of swing arm.
Exhaust hangers: Rubber flex mounts that hold the pipe to the frame.
Pipe to flange gasket
Pipe to silencer coupling.

These are all things that wear and/or deteriorate over time.

Good luck with it!

Rod

 

[Nismo3240]

awesome. I know it needs brakes front and rear too, so thats whats keeping me from riding it, I rode it in the winter in some snow but it was on a small farm, so I didnt get it going much out of first but it felt okay, a little sputtering. I cleaned up the pipe and flange and theres no gasket or o-ring whatsoever, and the flange is integral to the head. so I will be ordering a new gasket and a carb gasket kit. I went to a local bike shop and one of the guys said to just use some shoo goo on the exhaust, but that doesnt sound like a good idea, and I dont want to do a hack job anyways. I also hear a squeak when I pushing it around, its coming from the rear and I am guessing its the bearings.

 

[digifox]

if its been sitting awhile Check your pipe....mice like to bed up in them

 

[pre-game]

if its been sitting awhile Check your pipe....mice like to bed up in them

lol flying mice!! check that air cleaner too!! who knows how dirty it could be...

 

[_JOE_]

Yup! Kinda like them cannon things they shoot people out of at the circus.

He's right. Little critters can reek havok on things allowed to sit around for a long time. You might as well pull the seat and tank and look closely at the wiring, filter and airbox, too.