1980 Suzuki RM 125

[claerhout]

I've got a 1980 RM 125. It seems to have good compression around 150. It is very boggy. Between all of the gears it just seems like it has no meat. The bike also seems rich. It has stock jetting, pipe, piston, etc. I cleaned the carb, checked the air filter, and I just can't seem to figure it out. Any suggestions? I know these bikes were slow, but a pw 50 is faster than this hog.

 

[wirefryer#85]

3rd time responding, hope it gets through.

Since you have decent compression and she seems to be running fat, I'd look at these. She obviously can't breathe as in starved for fuel or can't get it out the back end, it should scream!

(no inference intended on your mechanical skills.)

Pull the intake boot and check the reeds, if they are even remotely warped , replace them, I recommend Boysen dual stage reeds if you can get them (about 45-50 $ U.S.

Is the pipe badly dented, especially right at the head?

After 26 years of owners, somebody ran a bunch of convience store 2-stroke oil thru it. Check the pipe for sludge build up.

Pull off the silencer and make a couple passes down the block,
not at 1 am :ohmy:

Pull the fuel line off at the CARB and see if it has good flow.

Did you 'cook' the carb or just hose it out with carb cleaner? These Mikuni's are a bit fussy about how clean they are inside.

Check the carb floats for saturation AND if they pass, check the float levels.

Remove the 14mm nut off the bottom of the float bowl and check for ANY kind of grunge build-up as this is your main jet fuel well.


Try these out and maybe she'll run good, the ignitions on the Vin/Evo series RMs usually either work or they don't but don't rule them out either.

Good luck!!

#85

 

[Britt Boyette]

These are really great tips but the one other thing I would check would be the airfilter. Get a new one no matter how great the old one looks. Uni makes them for you application.

 

[jefpel_1213]

Also check the plug to see if is fowled up

 

[wirefryer#85]

Britt and Jef are quite correct, foam air filters do crazy things and evo/vin bikes do a good job keeping up NGKs' bottom line, plus these are easy to check, throw a fresh plug in and if that don't change anything pull out the air filter, clean the airbox good and go make a pass or two, both should be another clue to your problem.

Tim

 

[Pantera]

after you check everything that the other guys said and you are still having problems, its you stator

 

[wirefryer#85]

Oops', forgot one thing, and don't take this as an insult but is the choke button pulled to the up position? Up is choke on and down is choke off, when the button is pushed down after a cold start it should make a kind of firm 'pop/click' to confirm being out of the way.

I have smoked one stator after the crank bearings wallered out. After a grand or so (new cases, crank, blah, blah ,blah :bang: ) the stator I didn't replace caused foot long flames out the silencer no matter what I did to the timing plate so like Pantera said, it could be just that!

Might want to look at Ricks' Performance Electronics out of DennisKirkdotyouknowwhat, or try getting it rewound, stocker replacement is a bit pricey.

#85

 

[dirtdealer726]

Thanks

Thanks for the help guys.