A Couple of Exhaust Questions

[PCMAX]

1-/ Just wondering how you guys deal with leakage at the exhaust flange? My 82 CR125 was meant to have a seal (#12 in the pic) but they're no longer available. I would imagine excessive gas leakage would also affect performance. Opinions??

2-/ Even though my plug colour indicates I have the mixture correct there is heaps of gooey oily crap around the exhaust flange and down the front of the motor at the end of the days riding. Not really keen to go for a smaller main jet but there does seem to be a lot of unburnt mixture dribbling out 

[TT5 Matt]

don't worry about it rm's from A up and yz's don't have seals just a slip joint,bad side is yeah you got a mess to cleen up after each riding day

[Lozza]

That's HP oozing out, and your jetting and ignition is not correct if you have oily deposits in/on the pipe. Make another flange that uses 2  viton o rings.

[oldyzman]

I have used quite successfully Very High Temp Silicone (red in colour). obviously Lozza has a better solution to the problem.
Brett

[SON]

Lozza is right on all counts
O Rings will fix the leak
it is Horsepower that is leaking
And your air/fuel/oil mixture is not right
Leaking even more HP.

[Hoony]

I have used quite successfully Very High Temp Silicone (red in colour). obviously Lozza has a better solution to the problem.
Brett

Yes i do the same. its a quick fix but does not last. need to do it regularly

[80-85 husky]

To Use silicon join area must be spotlessly clean, lavish it on and assemble it and leave it for 24 to 48 hrs before running. you should get a few good rides before it starts leaking.

To reduce the splooge  (American term for black sludge) try using motorex  fully synthetic 2 - at 60 or 75 to 1. This has reduced the pooh on my old 400 husky dramatically. if your a 32 to 1 man, you may see your jetting richen slightly if you do this.

i've run my husky and ktm 300 on this stuff as lean as 100:1 with no worries (3 years of testing) just did the kato top end and all was good, easy to clean the power valve as well.

[John Orchard]

Yes Lozza & son are correct, your jetting is wrong somewhere in the fuel curve, you may have the right main jet for full throttle (and main air bleed for high rpm full throttle) but the needle could be too high (half throttle) or pilot jet too big (idle to 1/4 throttle). Don't get me started on pilot air screw, slide cutaway, needle taper and needle jet.

When I got my KX250A5 it dribbled black gunge from all joins in the pipe, now I have the jetting correct (it turned out to be a badly worn needle jet), no dribbles anywhere  :-)

[EML]

A quick fix....never used on this forum by any members....is to use a roof and gutter sealant (black) cheap and nasty but will work fine. The red silicon is for very high temps but also for oxygen sensors were as the CR doesn't need that. We have (had) used black silicon for years until oxy sensors came on line about 10yrs ago. Don't use tile and glass sealer as it has an etching agent and it will make everything rust.
The black silicon will burn to a nice rubbery gasket and will (should) last between rebuilds. If you have time put a small bead around the pipe and let it go (almost) off....as good or better than a 'o' ring.

[pancho]

 on my XT I use an exhaust flange composite gasket as fits some Toyota ex flanges. Go to Repco or Auto One or the like with measurements, the have various sizes in stock.
 cheers pancho.

[EML]

Or talk to an exhaust shop, they know more than some dopey kid at Repco