KFX has some probs

[fast_enough]

Alright, heres the deal I'm gonna just tell you how it went and maybe a few of you can help me. I rode it 2 days ago, and it ran like a top. Then while riding it acted as if it had ran out of fuel, open lid up in take it looked fairly low, so I put it on res. But that did not help, so i made the trip home. Then I went ahead and put gas in it and filled it to about half tank at least. Still ran like this, so I pulled it in the shop, and heres how it acted. It would almost rev all the way up, but it would cut out and miss trying to get there, but it would almost rev all the way up when you held it open, then it would drop all rpm's and then rev back out and drop down and it would repeatedly. So I tear it down, check plug, some carbon build up, so I cleaned it and put it back in still same results. So then I cleaned the carb repeatedly also checked all lines for pressure and it all checked out. I cleaned the filter and I checked to make sure the choke was working properly, and again everything checked out. Also I cleaned the tank and all its components, and checked the spark and it was great. I checked a few other things out, and everything is checking out. I had the motor rebuilt not long ago, and spent $1100 just so I knew it got done right. I know of all the timing issues with these, but I donbt believe thats the issue with mine, it just seem like it to me. The motor sounds great and tight inside. Quad doesnt burn oil or anything. I'm thinking its electrical and possibly the CDI, I've heard of problems with alot of the CDI's too. But I'm no expert mechanic, let me know what yall think. Any help is appreciated greatly, thanks again.

[HondaRacer300ex]

It sounds like it's running too lean or too rich. Your jetting may be a LITTLE off.

[fast_enough]

I believe its jetted properly, it may not be, but still. Why would it run like that all of the sudden because of jetting? It has been running with the same mods for months. If you know what I mean.

[zeus54]

i think hondaracer is right you should bump down some sizes in your main jets or try raising your needle jet up one clip.buddy of mine had a similar issue ran a 165 main throughout summertime and into fall but when it started to get cold it would die under full throttle and if you tried to just blip the throttle up slowly it would work sometimes but not always, so agian my advice is play with your jetting. the needle controls 1/4 to 3/4 throttle while your main is a little on before 3/4 to full throttle. any body else out there disagree with what im saying

[z400clone]

^^^ Yep, I disagree. The weather did not change 50 degrees while he was riding.

Have you put the tank on "pri" to make sure the carb is getting plenty of gas? Leave it on pri and see if that that fixes your problem.

What does the spark plug look like after you cleaned it, ran the bike some, then put it back in?

Can you switch the cdi out with a friend that has a z400?

[zeus54]

not to get into a pissing contest but temp and humidity effect jetting just as much as altitude. all im saying is for the 30 minutes it would take to do changes in the carb might settle it down and if not then i guess i'll send him my cdi if he doesn't have somebody to help him :rolleyes:

[z400clone]

LOL yes I know, but he probably didn't climb 2000 ft elevation either. He went back to his house where he probably jetted it in the first place. Yes I know it all makes a difference, but I'm just trying to give him a reasonable answer to his problem

[fast_enough]

I've done everything listed above, and I did check the plug and it looked perfect. As for the CDI, I had buddies I could've used but I didn't know if something electrical might've fried mine, so I didnt want theres to get fried and me stuck with paying for 2 lol. I dont think it would have hurt it. But I called the shop and they said if it was anything they worked on when they did all the work to it, that they'd replace it free of charge. So we'll see how it goes. Thanks for the input

[z400clone]

Well if you are scared about frying his cdi, then see how your cdi works on his bike........

[fast_enough]

Originally posted by z400clone
Well if you are scared about frying his cdi, then see how your cdi works on his bike........

Damn, never even thought about that, its ok though as soon as I made my last post I took it to the shop. There finally gonna look at it tomorrow. So I might have it Saturday.

[hardkoratvmxr]

sounds klike the main jet fell out