One of the kids that ride with us has a KX80 that covers the swing arm with oil from the exhaust by the end of the day. He is using Maxima oil @ 32:1, the bike is running strong and starts on the first crank everytime. Why would so much oil reach the exhaust?
Running way too rich. Probably a jet size or two. do a search on this site for spooge and you will find quite a few hints on jetting but basically it comes down to too big a main most likely.
I have just been through that same problem. My son rides a 1989 KX 80 with an FMF fatty pipe. It was running very rich and the joint from the pipe to the muffler was almost dripping oil after a day of riding. Alot of smoke as well. But the bike ran well at the top and started on the first kick even when it was cold. I ran the gas back to a 36:1 & jetted from a 130 down to 112 then moved the needle back up to normal postion. Adjusted the clutch and geared it from a 14 front sproket to 13 & from 49 to a 54 on the rear. It is a real easy and smooth ride for my son.
Is the little rubber boot that seals the pipe/silencer junction missing ? Maybe get some silicone or some hose & hose clamps . If it runs good and has been for a long time and doesnt foul plugs maybe hes better off mnot leaning it out . It sure is a bummer to seize up a KX crank .
Our CR80 does the same thing, we run Maxima @ 32:1 and it always spooged somewhat. I added a fatty pipe and turbine core II and now it is downright messy, it drips out end of end cap runs down silencer & drips on swing arm. It also coats the rear fender. I am reluctant to lean out jetting even though FMF recommends it because it starts easy, runs great, and never fouls plugs :confused:
I am still having the same problem with my son's YZ85. Tried going down more on pilot and it wouldn't hardly idle. It would bbwwoogg when twisting the throttle while sitting still. Funny thing is, it runs good and starts good. We only ride trails and harescrambles. After 3 long races and a dozen trail rides, it still has the same plug. I have even tried different oils, but I haven't tried different mixtures. I've read that 32:1 is highly recommended on these mini's
since they turn so many rpm's. Sure does make a mess. Wish I had an answer.....
On our Cobra's we run 40:1 They spin 16,000RPM. I haven't had any problems. Spooge means pretty much one thing. Rich mixture. Not trying to be crass but FMF reccomends you run leaner because the new waves created by the pipe pull more fuel/air in. Just drop one jet size and see where you are. I have had plenty of bikes that spooged and ran good. then when I dropped one or two jet sizes I was amazed at the difference. Don't settle for the good power when the Great power is a jet size away.
I'd say search spooge again but Its disabled unless your a support team member.
Just do a plug chop when your done and you will know if your in the ballpark. Usually when serious spooge exists you drop one size and then your plug no longer has clumps of carbon on it. then drop another and the black plug goes to grey. You can stay here to feel safe. Or go one more and get the tan plug and you' be right in there.