87 rm125 help please!

[Hadley]

hi, Ive got am 87 rm125 that wont seem to idle, and there is quite alot of oil coming from the begining of the expansion chamber. Also is real smokey idling,(holding the throtte open a wee bit).
Any ideas or suggestions would be greatly appreciated.
Cheers.

[Motu]

Throw out the fuel and drain the tank,make a fresh mix at the correct ratio - and if it still does it then look at idle setting and jetting.

[Hadley]

Thankyou, Will give it a try.
Cheers

[Wellyman]

check all those seals on the pipe, replace seals, fresh gas and should be sweet

[F5 Dave]

After a gazillion year the oil will build up. Clean out the pipe & repack the muffler (will go better & be quieter). Clean the airfilter or replace. Most bikes produce excessive spooge when they are too rich. Some will happen.

Also it will be worn pipe to barrel interface.

Spooge is created by rich jetting where some unburnt gas is expelled due to incomplete combustion, because it is too rich –there ain’t enough air in there to burn all that gas that was sucked in. In this unburnt gas is the same oil that you mixed with it when it lived in your gas tank.

There is confusion over oil to gas ratio vs gas to air ratio
Oil ratio is not your problem & anyone who says so needs a slap in the face with a wet kipper.

Your task is to find out where it is rich, pilot, main or all of the above. Guess one is pilot jet.

Read a jetting article & fiddle some brass. Or just clean it out, service the filter & leave it be.

Mx bikes often don’t idle. Esp if the throttle slide is worn.

[Hadley]

Choice, cheers for the help.
Any ideas how to fiddle the jetting?

[F5 Dave]

Yeah, do a search on the net & you will find something far more comprehensive than we can type in a few words. Try Eric Gorr's site but there are plenty more. two things though
1. make sure you clean the airfilter/repack the muffler before doing any jet changes
2. Consider how long it has been since a rebuild. Just as the bike is old doesn't make it any less a race bike it was designed as. They got huge performance from a 125 by building it on the edge.
3. (so I lied) how much is the spooge really bothering you? I'd change jets if it is blubbery rather than a cleaning issue.

[Hadley]

Thanks.
Rebuild was quite recent, about 7 hours riding.
Spooge isnt really an issue for me, unless it goes all over the garage floor (girlfriend owns the house).
Bike is really a weekend knockabout toy, although obviously i'd like it to run like it should.
Whats this you say about Packing the muffler?
And how would i do it?
sorry, have to excuse me noobeeness.
Thanks again.

[F5 Dave]

Well if you do a search on muffler repacking you will find something try DRN.net. Basically the muffler will be riveted together, you drill the heads off & slide the sleeve off (with some effort) & will find the packing has gotten blown out/ caked in gook. Runs best when freshly packed. Any bike shop will carry muffler packing. Pink batts in a pinch, but no where as good.