Rode my KLX into work this AM like any other day. Wednesday is my favorite day because I take the bike out at lunch for a thorough 2 hour thrashing - keep a set of riding gear at the office for the occasion.

Almost into town, the bike started running rough - surging. Then it just stalled completely.

I stopped at the side of the road and it started right up. But, as soon as I give it any gas at all it stalls out again. Starts and idles just fine every time. I was even able to leave it in idle and put it in first to walk it up the hill to a friends house where I could leave it and not worry about being towed, ripped off, etc.

My first thought was a bad gas tank vent so I opened the cap, started it up and same result. I wondered if it was something to do with the new Vortex throttle I installed yesterday but it stalls even when I open the throttle by hand at the carb. Doesn't matter how slow I move the throttle - get a few RPMs above idle and down it goes.

Still at my friends house but I'll get it home at lunchtime. It's clearly not the clutch or sidestand cutout switches because I was able to walk it in 1st at idle RPM.

My 1st thought is carb. Maybe a torn diaphragm or a needle issue. I first thought maybe my mixture screw dropped out but I don't think it would even idle without it. Does the collar ever come off that N1TC needle? Didn't seem like even a good friction fit when I put it on.

Don't think it's electrical for the same reason - wouldn't start at all.

Any other ideas for this evening when I start the teardown? I plan to start with the easy stuff - tank off, pull the top of the carb before thinking about pulling that shecat of a carb.

Thanks in advance.

 

I had the needle drop out of slide a few years back. Same symptoms.

 

Ill give you 100$ for it as is. lol

maybe dirt in the jets.... fuel issue.

 

Sounds like fuel/carb. I'd be looking there first. Drain the fuel and replace it with fresh, then clean the carb thoroughly - including jets (using a fine wire).

 

Thanks for the help guys.

!st part of the mystery is solved. When I opened the top of the carb the slide was in the up position. I was sure I was going to find a torn diaphragm but it's fine. Needle, collar and clip where just fine as well. So, I cleaned the slide put everything back in and the top on the carb and checked it with the gas remaining in the bowl of the carb. Checked out A-OK.

Put the bike back together and it still runs fine.

I actually rode it into work this afternoon. Never thought it would be that easy a fix.

Now, the 2nd part of the mystery. Why'd it happen?

My slide hole is drilled AND I shortened the spring, AND I was whacking the crap out of it this morning trying to pull off a 2nd gear power wheelie. Thought maybe the new Vortex throttle would put it over the top. Not quite. I can definitely flip it a little higher with the vortex but not to balance point with just the free/cheap mods. I have a KLX300 exhaust coming tomorrow. Maybe the extra HP or 2 will put it over the top.

Anyone else had their slide stick in the up position? Should I go back to the stock spring length?

 

dj, I'm wondering about shortening your slide spring AND drilling the slide. Usually the only recommendation is to do one or the other. It might allow a tiny bit of "stiction" in the slide and carb body to let the slide stick. Just speculating.

 

Thanks TNC. That's why I asked. I was kinda thinking the same thing. I remember being torn over whether to cut AND drill. Couldn't really think of a downside at the time so I did both. I already ordered a stock spring today. It's a cheap way to find out if the shorter spring really made a difference or not.

I was also wondering if the power of the Vortex may have launched the slide into a place where it's never been (so not worn in so to speak).

 

I doubt it, the throttle only controls the butterfly on the carb and engine vacuum would still be the determining factor on how high the slide lifts.