KX 80 Jetting/Spooge

I posted a similar thread in the maintenace forum last week but didn't get much for replies so I'll try the mini forum since the issue is with an 80.

My son's 99 KX80 runs strong and doesn't seem to stumble or bog at anytime through the throttle, I haven't made a note of the current jets in the bike but it is spooging from the joint where the silencer and head pipe join. I am currently running Shell premium pump fuel 92 octane with Yamalube2 at 32:1, NGK BR9EYA plug (Was in it when we bought it and runs strong so stayed with that plug) Bike has never fouled a plug and like I said seems real strong all the way from bottom to top in throttle response so I'm not sure where to start as far as leaning it out to eliminate the spooge.

If I had to guess I would say it is one of the slow speed circuits as my son is not a super aggressive racer yet and I doubt he's WFO very often during his laps.

Anyone got any tips or should I just start with the airscrew and then move on to the pilot and needle from there and chart how each change affects performance?

Any advice appreciated as I'm reluctant to fiddle while it is running good as my mechanical skills are somewhat suspect :think:

Jason, Thanks for the tips, I'm probably going to start playing with it this week if we get time. As for the plug I am going to put a new plug in and start to check it more regularly, I'd be hesitant to take anything from the plug that is in it right now as it's been in there all summer. Never seems to be enough hours in the week right now. No sign of the tape yet but I'm sure it will arrive soon.

I started playing with it a bit today after riding his friends 00 RM80, the RM80 seemed stronger off the bottom out of turns so I figured maybe Troy's bike wasn't as clean as it could be in the slow speed circuits. I started with the air screw and noticed almost no difference at all from 1/4 turn out to 5 turns out. I then moved the clip up one position from the middle (3rd) to the 4th from the bottom. Just to make sure I'm thinking the right way here turning the air screw in leans it out and moving the clip up also leans it correct? As for throttle response at the lower thottle settings 1/4 and 1/8 etc should the test be just riding at a steady throttle setting and checking for a bog or crackle? The reason I ask is Troy's bikes seems steady but from about 1/8 throttle if I rip it WFO the bike kind of hesitates then hit's, if I get the revs up a little higher say closer to 1/4 throttle then it doesn't hesitate when wicked WFO. Is this just the nature of a 80 that it needs to be revving like crazy? or is that hesitation a sign the jetting is off slightly? A quick fan of the clutch deals with any hesitation quickly and I just assumed that was the nature of an 80.

No real bog to speak of it just takes a moment of hesitation before it actually starts to "hit and this is only when rolling along at about 1/8 throttle and then grabbing a handful to straight WOT, if I'm up around 1/4 throttle it hits immediately and lifts the front end. It does tend to smoke a fair bit as well (silencer repacked last week) so still think it may be rich somewhere. Going to play with the airscrew more tonight and then hopefully this coming monday I have a day off and I'll mark the throttle and go through the procedure listed on Eric's site for dealing with each circuit.

Can anyone confirm should this 80 be able to rip the throttle WOT from an 1/8 setting or barely rolling and have it hit immediately or is the hesitation normal? I don't want to chase my tail searching for an answer to something that is simply a characteristic of the bike.