Help Please!!

[CmyBackULose]

Got ready to go to the races today, so I fired up the stock Kasea 50 this morning and it was cutting out. I took the Keihin 20mm carb apart and gave it a good cleaning. So I restarted it and same thing it was acting like it was flooded when you gave it gas. I changed spark plug with same results. Since then I have cleaned carb 6 more times with the same results everytime. I checked the spark plug again and it looks fine. I also checked compression and I am running 129 at full throttle. What should compression be? Any other ideas on what could be causing me this headache?

Thanks
Cooper

[Sjorge450R]

compression sounds good... check your air filter, make sure it isnt damp.

[CmyBackULose]

Tried different air filter, no air filter. Have jetted down one size on main also. Same results. Checked exhaust flange for cracks.......nothing found. Drained gas from gas tank and replaced with new mixed gas. Nothing is making a difference.

[Sjorge450R]

after my race today, my predator 90 is doing the same thing. And i dont know whats wrong. I think it is inbetween getting too much and too little air.

[Arctic Cat Dad]

Check the intake for leaks or cracks. If your running the koso intake with that keihin carb, some have been having them crack in some places.

[CmyBackULose]

Originally posted by Arctic Cat Dad
Check the intake for leaks or cracks. If your running the koso intake with that keihin carb, some have been having them crack in some places.

I am running the Koso intake. I remember seeing the cracking problem so that is one of the first things I checked. I appreciate the help guys.

[qwadfather]

Lucky 7 has the cure for the common Koso! Loook at http://www.lucky7racing.us/ Had to plug our site a little. But...we use this because of our own round of headaches with the Koso and a couple of other types of intakes and I wouldn't feel right if I simply sat on a solution without telling anybody. Even some of the stock intakes are butyl rubber. Throw one in a few ounces of gas and leave it for a few days, lol! What gets blasted through your intake? Why, one sort of solvent or the other! Anyway, didn't mean to stray off subject but maybe I enlightened someone. As always, Ride safe everyone, Ed and crew.

[Sjorge450R]

i tried 3 intakes at the race
it cant be that'

[AtvMxRider]

Replace the plug.

[Sjorge450R]

tried the plug too. Went from a 7 to 8

[AtvMxRider]

Check your stator

[Sjorge450R]

thats all clean too. I ran perfect the day before the race and then when we went up higher in altitude for the race it quit working. Who knows if it works now. I havent even tried to start it

[Sjorge450R]

alot of other 90's were doing the same thing but theres straightened out after the first couple laps

[AtvMxRider]

Originally posted by Sjorge300EX
thats all clean too. I ran perfect the day before the race and then when we went up higher in altitude for the race it quit working. Who knows if it works now. I havent even tried to start it

Well you just aswered your ? If you went up in altitute your jetting is off.

[qwadfather]

Up in altitude= leaner jetting (smaller size fuel orifice to compensate for reduced oxygen/thinner air)
You guys aught to live at 4500-8000 feet above sea level. None of the gurus seem to be able to recommend jetting that's even close, so we have to get pretty good at it up here! What elevation were you and what elevation are you usually riding. The bikes that started to run better simply ran enough to lean out their air filters, already jetted fairly close. If yours failed to run out better after a while, try to bump your main down in increments of 2.5 in size (ex. 115 down to 112.5), if you have'em handy. If not, use .5 increments (ex 115 down to 110), but don't forget to do a plug chop every time! If you think you got'er running too good to be true, YOU DO! Check the plug! Unless you went to drastic changes in altitude, (over 2000 ft, someone correct me if I'm off.) your pilot should be OK. A little air screw adjustment will be required, however. Midrange may require you to move the clip on the jet needle up one notch (leaner),( but probably not.)Some hints are Patience. These smaller machines are finicky. Don't get desperate and start guessing at what to do next. Take notes so you can remember what you did for the next race at this track. DON"T forget to put in the original jet when you get back to your home altitude. You WILL run it too lean in a hurry! Last but not least, Ride safe. Hope I've helped, Ed and crew.:)