3/4 to full throttle problems

[jolly green thumper]

At 3/4 to full throttle in all gears engine is running poorly. I have cleaned carb, air filter, new 94 octane gas with octane boost (+2) with Klotz oil at 40 : 1 and new plug. Problem has not cleared. Engine is not bogging but sputters. I think it's running leaner at higher revs. Dealer I purchased the bike from told me it needed to be run at higher speeds to blow it out. I have ran it at full throttle in 5th gear but problem has not cleared  Is this still a carb problem or something more involved ? Any main and pilot jet sizing or needle jet adjustment suggestions ? Also have to kick the hell out of it to get it started. Usually 20 kicks to get it going. Right foot is getting a little sore. Any tricks to starting the beast a little quicker . From idle to 3/4 it runs great no problems at all.

Mike

[Arigato]

Run it full throttle again and hit the kill switch while wfo.  Pull the spark plug and tell us what it looks like.

[gowen]

It's running super rich. Things to take a quick glance at: Powervalve opening?  What is your needle position/Needle #, Mainjet #, Also how many turns is your air screw in?, and make sure your choke isn't on. lol

When doing a sparkplug test, make sure the sparkplug is new. Because if you have been running it rich for sometime it will be black.

Get back with the mainjet # (stamped on the side of the carb). Also, just for kicks, try raising the needle clip (dropping the needle) and see if that is of any help.

[hughes]

How is idle to 3/4 throttle?? Carb flooding out one of the vent lines??

[doordie]

Put in a large mainjet until it?s "fourstroke" and then lean it down from there.
(A stock K5 have 165 mainjet, put in a 180 and go down from there).
55-60 pilotjet with stock reedcage.

Clean filter in gastap to,blow it,dont suck .


If problem don?t solves,check inside exhaust port that KIPS moving and don?t "hanging down" or stuck.

[FuriouSly]

All good info here.  Plug Check - Power Valve opening? (pull the plastic cover above water pump and check travel of powervalve) - Go big on jet (180) and come down - needle does mostly 1/2 throttle area (where main jet works great WOT but throttle is sluggish just getting on the pipe) -  kickstarting issue? look here --->  http://www.kxriders.com/forums/index.php/topic,2169.0.html

Have you resolved the issue yet?

Sly

[jolly green thumper]

 Finally had time to look at the problem again. Used a can of carb. cleaner the first time . Friend advised me to use lacquer thinner and to soak the whole carb. in it overnight to remove varnish. Put in a 165 main jet(down from 168), and new Boyesen Pro Series reeds. Bike runs great, and pulls very hard 3/4  throttle and up. Thanks for all the suggestions. Love this site.   

[jolly green thumper]

Forgot to mention the starting trick with a few slow kicks, rocking the bike in second gear, and then kicking it like you mean it works like a charm. Started on the second try.

[kx666]

Forgot to mention the starting trick with a few slow kicks, rocking the bike in second gear, and then kicking it like you mean it works like a charm. Started on the second try.

make sure your at TDC when you kick over the bike. i have seen them throw people into the handle bars...   

[Polar-Bus]

At 3/4 to full throttle in all gears engine is running poorly. I have cleaned carb, air filter, new 94 octane gas with octane boost (+2) with Klotz oil at 40 : 1 and new plug. Problem has not cleared. Engine is not bogging but sputters. I think it's running leaner at higher revs. Dealer I purchased the bike from told me it needed to be run at higher speeds to blow it out. I have ran it at full throttle in 5th gear but problem has not cleared  Is this still a carb problem or something more involved ? Any main and pilot jet sizing or needle jet adjustment suggestions ? Also have to kick the hell out of it to get it started. Usually 20 kicks to get it going. Right foot is getting a little sore. Any tricks to starting the beast a little quicker . From idle to 3/4 it runs great no problems at all.

Mike

Could also be you are simply in need of a new top end. Do the "plug chop" read first, as this is a simple test, and tells you all you need to know about exactly how you are jetted on top end. Keep in mind, even jetted stock, a KX500 will pull excellent. Once you lean them down a bit, then they REALLY start to haul the mail on top end.....