I put on a Big Gun Exhaust, installed a Dynojet kit and a K&N filter in my KLR650 last week. I ran it, worked great. It was colder out then, about 45 degrees, everything worked great, idle, mid range and top end.

Today I go drive it in town, its 70 degrees out, ran in 8 miles on the interstate, ran great. Picked up some stuff in town, drive back home and get caught in rush hour traffic...running first gear most of the time, stop and go....it starts to die on me. I keep it running, but its stumbling at low rpm. After about 4 miles of this crap, the traffice starts to pick up...its stumbling but eventually I get cranking by everyone. Seems to run midrange and up. I get off my exit and it starts running okay.

I get home, go out about 15 minutes later, try to start the machine, it won't run for crap. Hard to start. I get it started, but missing low end.

So I read the Dynojet instructions, says when it starts hard after being warm, its most likely rich. I can't figure out why it was running great and then doesn't run for crap. So I figured I fouled a plug, so put in a new plug, same thing, running like crap. So I lean out the air mixture screw, no help, won't idle.

I take out the needle, I had it on the 3 position from the top, I try to 2nd position, same thing, try the 4th position, still runs like crap.

So....I put the stock needle back in, still runs like crap. I check the new plug, black....definitely rich. So I put the stock Keihin jet back in, still runs like crap.

I put the dynojet needle back in, still on the 4th position from the top, with the stock jet, still runs like crap. The Keihin stock jet is a 148, the dynojet jet I had in there is a 140. Apparently they don't correspond in size, so not sure how the one compares to the other.

So anyways, tired for tonight. I plan on putting the stock needle back in with the stock jet in the morning and see what happens. I'll put the air mixture screw back to 1.5 turns out from bottom.

If I have to, I will put the stock air filter back in and the stock exhaust back on with the carb stock and see what happens....

Anyone have any idea's?

dave

 

I don't know too much. I would check my vent lines from the carb and at the tank? Check plug wire real close. Check grounds. Check throttle cable for play - maybe it thinks it is like Polaris and sees slack and thinks you are stuck wide open?

 

If you get the float bowl off, check to see if the pilot jet is still tight. could the choke be sticking on?

 

If it ran okay for while, it sounds like you've got something else going on. I'd check for trash in the needle and seat and adjust the float to specs. Loose jets would be something to look for too.

 

i know how you feel elkbow. i'm soon to be changing the pipe on my pred. it sounds as though you're rich on the pilot jet. if it runs good in the mid and top but not on the bottom, the only thing left is the pilot. i'm not a jetting expert and this info is not from your pipe manufacturer but check it out. there are some tricks to try to see where you are at.

jetting

jetting


maybe this will help maybe not.

steve

 

Thanks guys for the inputs. I've checked all the vent lines and vacuum lines. I pulled the carb again, float is to spec, jets are clean. I wish I would have done a plug check right away before this happened to see if it was running rich then.

If nothing else, I'll put everything back to stock and see if it runs. My guess is that it won't and something else is wrong since it was running fine when I first put everything in....

any other inputs are welcome....I've sent an email to Dynojet, but won't call them until I've tried everything...

dave

 

Yes , it does sound like trash in the needle and seat

This is usually representive of loading up at an idle , but when heavy on the throttle it's ok

When this symptom occurs you can cheat , .......... turn off the fuel to the carb , .............. let it run till it dies , ................then turn the fuel on and start it up again , ..........this procedure 90 % of the time , because the float and needle have droped wide open , will allow the dirt to be flushed into the float bowl and get you home without loading up on fuel till you can remove the float bowl

 

I inadvertently installed a main jet n place of my pilot jet on my three weheelr once and had the same problems your describing, so I think it could infact be that its two rich. once started up it would idle and ran fine. After The motor would get warmed up ,I had to use the throttle to keep the trike idleing or it would just die out on me.

just my 2cents.

 

I've done alot of work on carbs, won three regional championships and two national championships in the AMA CCS series roadracing circuit, so I know the difference betwee the pilot jet and the main jet...but thanks for the info....Dynojet doesn't change the pilot on this kit as with most of their setups....except on the exup series yamaha's mainly....

Got the carb all back apart now, just in case I'm going to hose it out with carb cleaner and blow it out with compressed air....then I'm going to put everything back to the way I first installed it and then go from there....

 

elkbow didn;t mean to make it seem as if you were dumb, when I made this mistake it was the first rebuild I had ever done.

my intention was that maybe if the pilot was two large in the kit (wrong one could have been sent to you) it could be causeing your problem. just trying to help you trouble shoot.

good luck, im sure you'll figure it out.