Finally took the bike out for it's first ride of the year today. Over the winter, I'd start it up once a month and let it idle until the float bowl ran dry then I'd put it away for the rest of the month then do it again. The bike would always start fine with the choke on, then as soon as it idled up to 3000rpm, choke off and it idled nice around 1300rpm or so until it ran out of gas, no problem at all all winter. Took it out today and for most of the ride it seemed fine with no problems at all. Was about 10km from home and it started to stumble and die so I switched to reserve and it picked up again for about another 2km then died and wouldn't start again. I thought it was out of gas but when I looked in the tank I could see and hear fuel sloshing around but I gassed up anyway.

As soon as I tried to start it again it wouldn't fire. Pulled the choke out and it fired right up but idled around 5000rpm and as soon as I put the choke in it would sputter and die. Made it home the last few km's by keeping the rpm's up enough and the choke in so it wouldn't die in traffic and when I got home, same deal, would die and not start with no choke and idled insanely high WITH choke........anyone have any ideas what the problem is? It SEEMS to me like it might be a vacuum leak somewhere but has anyone else had a similar problem??? I'm gonna go out and pull the seat, tank and front plastics and see what I can see but I wanted to share with you guys and hopefully get some input.


Thanks in advance!
Tony

 

You have a plugged Jet. Happened to a guy that I know, 5 minutes into the ride all he could do was idle back to camp with the choke on and head home. Ended up taking off the carb, and cleaning out the jets and the gunk in the bottom of the bowl.

 

also, if you are de-smogged, check your vacum plug on carb. the cheap rubber ones from the auto parts store may have cracked and is leaking.

 

+1 To what Tmoe said. Happened to me once. Was suggested to me to use vinyl caps.
Dan

 

Like this.

 

wierd.....I pulled everything off including the airbox lid, started it up and it "seems" to run fine.......gremlins I guess

haven't desmogged yet but I read on here about the auto parts plugs sucking so I'll see if I can find some vinyl ones. If it's nice out tomorrow (getting cold and dark now) I'll pull the carb and check everything over and clean it out, hopefully it was just gunk in the tank that temporarily clogged a jet and worked its way out but I don't wanna get stuck on the road or trail somewhere with this again.

Just out of curiosity, does the choke bypass any or all of the jets? Why would it run (albeit idle high) with the choke on and not without?

 

Like deej said you may have a clogged jet, and by your described symptoms, the pilot or low-speed jet, which is quite small (~.012"). Sometimes these get a microgoober in them, and the bike won't start well or run right or if the jet is mostly blocked the bike will run only with the choke part on.

Fuels with ethanol can be a problem, not because there's anything wrong with ethanol as a fuel, but ethanol likes water - a lot. It can absorb water well, but if your fuel has too much water, and your bike sits for months, some really weird stuff will precipitate out and evolve into ghostly cheeses. As long as you are using your bike regularly, somewhat wet fuel will hardly be noticed. Gasoline-ethanol that gets wet plus sits a long time can really ruin your day.

The chemicals like Sea Foam people recommend may dissolve a bugger, or just be money spent. Many of these additives contain mostly alcohol... the stuff that's 10% in most of your fuel anyway! I really have no way to prove they work or don't.

Sometimes the problem will mysteriously disappear, only to pop up again for no sane reason. That's because the obstruction can move around microscopically, clogging the jet to varying degrees. Sometimes removing the fuel screw (don't lose the washer and o-ring!) and pulsing pressurized air in the hole will dislodge the bugger. Sometimes you just have to go in and carefully check and clean every circuit and hope you got it.

I had this problem pop up on my KLR650 the DAY BEFORE a long trip to the Pacific Northwest. Not a fully clogged jet but had to use the choke later into warmup. Desperate, I leaned the carb over and did the fuel screw air pressure trick, and that helped (it would run without the choke), but it ran a little lean down low, causing too much engine breaking when the throttle was closed, which cause performance to be jerky. The fuel screw was also not responding as it should have, which was more evidence of a clogged pilot jet. I just screwed the fuel screw way out and put up with it, as the KLR650 carb is not fun to remove outside a shop. A couple weeks later in Washington, something dissolved and the problem went away and has not returned.

 

I'm not too sure if the bike is even jetted correctly either. I noticed last fall after I jetted it that if I let the throttle off all the way and compression braked to slow down I'd get some light popping out of the pipe but today when I did the same thing it sounded like it was almost backfiring the popping was so loud.......would that be the pilot jet as well?

I have the fuel screw out the usual 2 and a half turns, stock pilot jet and a 128 Kawasaki main jet, N1TC needle on the 3rd clip from the top and a drilled out slide.....and the other mods you see in my sig. I'm PRETTY much at sea level (280') so I'm not sure if these are the right jets to be using. It seems ok but at higher rpm's it almost seems like it cuts out a tad or sputters so I'm not sure if I'm too rich or lean or what.....any suggestions? I'm thinking about taking it to a dyno and having them fine tune it to eek the most performance out of it for the time being.

 

Try one of these. Another $ well spend IMO.

 

you might want to check and see if your slide is hanging up.
If it happens again, loosen the air cleaner boot and look into the throat of the carb.
I had the same exact problem when i used the DJ spring.
I think my slide needs to wear (lap) into place or something.
I only have 12,000 miles on it