KLR250 RPM hangs before dropping

[biketimus_prime]

Hi all,

I may have gotten my old KLR back after the owner was selling it again to get a better bike. I've decided to keep it and sell my hyobag because the KLR is more fun and I regretted selling it to be honest.

Anyway,

When I rev the thing, the revs go up and then hangs around 2500 before slowly dropping down to around 2k.
I usually does idle around 1500 when I start it and gradually turn off the choke. It's idling high after riding.

A slight counter clockwise turn of the idle knob brings the revs right down to barely idling and it will die. It is fully turned in as it is so that it idles fine.

I've cleaned out the carburettor and nothing was blocked. I've also drilled out the cap that blocks the idle mixture needle, only problem is that I can't reach it from either side to adjust it! I tried using a ratchet with the flathead bit on it but there's just no way. Is there a special tool? It did slightly improve after cleaning of the carby, was a lot worse (idled at like 4k before dropping slowly).

But the thing is, if the bike is 100% stock, the carby boots aren't damaged or anything, everything is in great condition, revs don't go up when I spray stuff around the boots either. I shouldn't have to adjust the mixture screw should I?

I admit I didn't adjust the float height. Could that be an issue...

[bogan]

Float height could be a factor, but it does sound like fuel screws are just set wrong.

[biketimus_prime]

Float height could be a factor, but it does sound like fuel screws are just set wrong.

I'm the first owner to have access to the fuel screw as it was blanked off by a plug until now. Had to drill it out to get access. I haven't adjusted anything yet though.

[haydes55]

Throttle cables? Choke cable? Choke itself? Air leak?

[biketimus_prime]

Throttle cables? Choke cable? Choke itself? Air leak?

Throttle cables snap and return freely with no issues
Choke works correctly
No air leaks not even exhaust leaks

[biketimus_prime]

Fuck it I went out again and had a proper crack at trying to turn the screw while engine and shit was cold so I can reach in better. Adjusted it about 2 and 1/4 turns out. She runs really well now! Revs don't hang anymore but more of a slow but sure drop. I also managed to turn the idle adjuster out about 2 turns to get the right RPM. Comes down and settles there just fine now. Is that acceptable that the RPM doesn't drop quick, it's more of a steady drop?

I guess I could richen it a 1/4 turn more and see what happens next time. Way better now though.
Can someone explain why I had to adjust it when nothing else was touched on the bike to begin with? Is it just wear and tear over the years? It's got 27,000kms

[bogan]

It should drop pretty quick, but not drop passed its idle rpm.

Age/filter/exhaust condition, air temp are all factors. Things like this do seem to show up around this time of year as it gets colder out.

[Gadget1]

Fuck it I went out again and had a proper crack at trying to turn the screw while engine and shit was cold so I can reach in better. Adjusted it about 2 and 1/4 turns out. She runs really well now! Revs don't hang anymore but more of a slow but sure drop. I also managed to turn the idle adjuster out about 2 turns to get the right RPM. Comes down and settles there just fine now. Is that acceptable that the RPM doesn't drop quick, it's more of a steady drop?

I guess I could richen it a 1/4 turn more and see what happens next time. Way better now though.
Can someone explain why I had to adjust it when nothing else was touched on the bike to begin with? Is it just wear and tear over the years? It's got 27,000kms



Here's some pilot mixture screw adjustment info:http://faq.ninja250.org/wiki/How_do_I_adjust_the_idle_mixture%3F

Don't worry about the fact they call it an idle mixture screw.

[nzspokes]

Read this. http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html

[biketimus_prime]

Here's some pilot mixture screw adjustment info:http://faq.ninja250.org/wiki/How_do_I_adjust_the_idle_mixture%3F

Don't worry about the fact they call it an idle mixture screw.

Cheers for the link, good idea for the screwdriver, might make one for next time. I was using the second option of a small bit with a holder.


Read this. http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html

Thanks! Really informative and easy to follow. I have gone with the assumption that the needles are all correct and it is running well bar the lower RPM operation. I don't know how a KLR should feel through the rev range though. It seems to pull well? I might just put my pride aside and accept that I don't understand how to tune the bike properly and take it to an experienced tuner who can give me a crash course in it :)

[Gadget1]

Cheers for the link, good idea for the screwdriver, might make one for next time. I was using the second option of a small bit with a holder.





No problem, there's plenty of other info on that site about engines, brakes, tyres etc.

Also, there's a mobile motorcycle tech in Auckland called George (The Motorcycle Doctor) for the finer points of tuning.

[biketimus_prime]

No problem, there's plenty of other info on that site about engines, brakes, tyres etc.

Also, there's a mobile motorcycle tech in Auckland called George (The Motorcycle Doctor) for the finer points of tuning.

Yeah George is the guy I will probably go to. I've bought about 5 or 6 bikes and of them, 4 have been worked on by George for the previous owners efore I bought them. He gets around! Haha

[biketimus_prime]

Took the carby out AGAIN and reset the float height. They were at 16mm rather than the factory 17. I was a bit pedantic and set it at 17.3 or so from what I can tell. Doesn't hurt to run a bit rich right?
What a difference it made! The bike idles perfectly fine now, and is very peppy than even after the first clean out.

Next thing to tackle is the cam chain tensioner. It has a manual one installed and I can hear it slapping a bit so I have to sort that. Then it'll be in to George for valve clearances because I'm to pussy to do it myself.

[biketimus_prime]

Holy this this thing wheelies easy as!!