I originally posted this topic on the Kawi forum, and a member there advised me to post it here as well, considering the KFX and the Z are the same quad......

I purchased by KFX a couple months ago.....I'm 35, so I've learned to take care of my toys and followed the recommended break-in procedure for the engine.....

Now, after 15 or so hours, I've started to open'er up......and have noticed, that when the engine is under a load (deep sand, ripping down the road in 4th or 5th gear or bogged down in sand while attempting to reverse out) the engine begins to "stall" or miss......It's really noticeable, and can create problems when I'm ripping up a steep hill......

I took it to the dealer yesterday, and all he said was this is a "common" situation with a lot of these engines, and I need to stop babying the engine and start hammering it!......

Today, I sunk the rear axle in deep, slimy mud, and couldn't go forward......when I put it in reverse to attempt to back up, the engine started "bogging down" and was running like crap!.....I had the trottle pegged, and it was missing, and sputtering.....I had to get off, spin the quad around!....

So....is it me, or is there something wrong with my engine?......Does this sound familiar to anyone with a KFX or similar engine?......

Please offer advice!.....

Thanks in advance!......

 

If you just have this problem in reverse, then yes it is a commen problem because the reverse rev limiter is set pretty low. If its in the forward gears as well, my guess would be poor jetting. Good luck

 

Ah ha!........so there IS a reverse RPM limiter?.....I'd thought maybe that was it, because it does sound like the engine is "limited" when the tranny is engaged in reverse!.....O.k...that does explain a lot.....

As for the forward "missing or stalling" problem.......still not to sure about that one......it doesn't happen all the time, and I really notice it most if I'm in to high a gear for the situation......like climbing a steep sandy hill, in 3rd gear.....once I shift to 2nd, BAM!.....engine recovers, and runs normally.....

Am I simply "bogging" the motor to much maybe?.....I haven't ridden ATV's in 15 years.....and I'm still not used to the RPM ranges......

Thanks for the advice!.....

 

The same thing happens with my 1992 Suzuki rm80 when i hill climb, race, and get past half throttle in higher gears. Never knew what caused is so i bought a new piston foe the he!! of it . I'll see what happens and keep you posted.

 

How easy is it to take the jets out and clean them?......considering the age of my engine, could it be possible the jet (jets) are clogged or dirty?.....

 

Jets probly dont need cleaning, but they might because this sounds like a fuel delivery problem. Check you lines and vent hoses. If you dont find anything to be the matter, try reving your KFX higher on hills. Stock is geared a little bit high and needs to be revved up a bit.

 

I'm going out to check the vent line on the tank right now.......I'll report the findings.....

Yeah, I noticed my KFX is geared higher.....much higher than my wifes Lakota Sport.....

Could this be a symptom of me "bogging" the engine by loading it to heavy in too high a gear?.....

(to add, my buddy rode my quad, and he noticed the same "missing, stalling" symptoms as I did)

 

nah....the vent line is clear (I've got a fresh taste of gas fumes in my mouth!), and the main fuel delivery line "appears" in good condition.....

I've got an appointment with the dealer to perform the first service next week.....I'm going to tell them AGAIN, that the engine isn't running right......although, it's going to be hard to explain, since it only does it when under a "load"......all other times it appears to run great!.....

Thanks again for the help!.....

 

Go find a nice hill and rev the **** out of it. I'm willing to bet you are not used to a machien being geared that high. Dont expect to goose your way up a hill on a stock KFX. Well you could but you clutch would be shot by the time you got to the top. [img]i/expressions/face-icon-small-tongue.gif[/img]

 

Yeah man, you're probably right.......I just need to get used to it more.......I wish this thing had a tach on it, just so I could have a ball-park reference for RPM's.......