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'07 KLR 650 stuttering or worse at 4-5k RPM when warm

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I've had some luck in the past with sticky float valves by turning the petcock off while the bike is running, riding until it starts to run out of fuel (float bowl empties out) then turn the gas back on. The flow of gas through the float valve sometimes is enough to flush out whatever crud may be in there.

If that doesn't work, I'd pull the carb, remove the float bowl and thoroughly clean out the float valve. While you're in there, clean the main and pilot jets and the main emulsion tube, too. Get a can of aerosol carb cleaner and use it all up, alternating with compressed air.

It would be tempting to do the 22 cent mod while you've got the carb in your hand, but I'd recommend you resolve the problem before complicating the situation. One thing at a time--that way you know what worked and what didn't.
 
A couple things when pulling the carb down and spray cleaning.
A. be very gentle with the floats, if you have a hard smooth surface, place the floats on it and eyeballl how they sit . Both floats should be equal in their place. Place them in a bowl of water, they should float equal.

B. Use brake parts cleaner, it evaporate quicker and is less likely to cause swelling in the nitril bits (rubber) Do not spray oil on your carb rubber bits, causes swelling.

C. Take a pipe cleaner to your passages and spray them out.

D. Take your time, it is gonna be cold for the next few days.
 
If I had more money in my life generally, I might not know how helpful people can be. I might have just had someone drop my GS off at the dealer for me and had them take care of it.
But, I bought a KLR for a reason. I could kind of afford it as a second vehicle, and I could conceivably work on it myself. I'm grateful. And, actually, at this point of my life, even if I got rich, I'd keep this bike, and continue working on her myself. Maybe not wait so long between farkles though.
I'll post again after I take the carb off and get into that.
Thanks everyone :-D
 
Well, that was promising. If heat has anything to do with the problem, than obviously today wasn't a good day to test ride, but for what it was worth, she ran great. Maybe better than ever.

I removed the carb, opened up the float bowl and removed all the little parts in that part of the carb. Sprayed the heck out of it all with carb cleaner and put it all back together. I didn't see anything obviously wrong while I was in there.
I was apprehensive because I hadn't worked on the carb before but, miracle of miracles, it started up fine when I got it all back together!
There was zero hesitation at any rpm. No stuttering at higher rpms, no cutting out. Power actually seemed subtly smoother on acceleration that I remember it ever being. There has always been a tendency to knock under hard acceleration but there was none of that today.
Time will tell...
 
Excellent! Was there a bunch of crud or varnish in it? Did you have to poke anything through the jets to clean them out? When they're clean, you should be able to look through the tiny little holes and see daylight (assuming it's not night time, of course ;-})

That clip you posted of the gas "pulsing" through the filter made me wonder if the float valve might be sticky, but in my experience they usually stick in the "open" position, causing gas to flow out of the overflow tube.

Another possibility: when you removed the carb, you had to disconnect all the hoses, right? Fuel line, vacuum line and vent line? If the vent line was blocked that could cause fuel starvation at higher RPM's when demand is higher, and when your removed/replaced it, you may have knocked some crud out of the vent line.

Glad to hear it's working better! Gives you a warm, fuzzy feeling, doesn't it?

Here's what I found in a carb off a '98 KLR I recently bought:

attachment.jpg


Runs like a top now that it's all cleaned up.
 
road_thing said:
Excellent! Was there a bunch of crud or varnish in it? Did you have to poke anything through the jets to clean them out? When they're clean, you should be able to look through the tiny little holes and see daylight (assuming it's not night time, of course ;-})

That clip you posted of the gas "pulsing" through the filter made me wonder if the float valve might be sticky, but in my experience they usually stick in the "open" position, causing gas to flow out of the overflow tube.

Another possibility: when you removed the carb, you had to disconnect all the hoses, right? Fuel line, vacuum line and vent line? If the vent line was blocked that could cause fuel starvation at higher RPM's when demand is higher, and when your removed/replaced it, you may have knocked some crud out of the vent line.

Glad to hear it's working better! Gives you a warm, fuzzy feeling, doesn't it?

Here's what I found in a carb off a '98 KLR I recently bought:

attachment.jpg


Runs like a top now that it's all cleaned up.
Click to expand...

Man that is one nasty looking jet! (is that considered a jet?)
The inside of my carb was pretty clean looking as far as I could tell. Nothing plugged up at all, although it almost seemed like the float valve/needle was kind of sticking but it was hard to tell. I wanted to see something that looked wrong but it all looked pretty good to me. I cleaned the heck out of everything while I was in there though because it sure seemed to me like a carb issue.
I had already checked the carb vent, which was kinked as a matter of fact, but fixing that didn't solve the problem.
The fuel filter looks a little different after the carb cleaning, in a good way. There's still no more than maybe a quarter of the filter body with fuel in it at any given moment while it's running, but instead of fuel dribbling in off and on like it seems to in the video, it now seems to be flowing slow and consistent.
I sure hope this did it. I wanna feel that warm fuzzy, but I've thought that I fixed this problem so many times before. Perhaps the problem was really in the carb the whole time?
I'll post again if the problem returns, or when I become convinced that the problem indeed was resolved by this most recent and hopefully last effort.
At least it forced me to get into the carb. It wasn't too bad and so now i'm looking forward to doing the 22 cent mod, and/or whatever other carb work I want or need to do in the future. Ride On! :rider:
 
That's what my fuel filters have looked like- 1/4 to 1/2 full, but consistent, not on and off like your first post. Hopefully you got it for good this time.
 
RIDE REPORT! :rider:

Still too soon to say for sure, but I'm hoping to punctuate this thread with this positive ride report after months of trying to solve the stuttering problems.

I had a very confidence inspiring ride today. The bike has never run this good. Sure hope it stays this way for awhile.
Went to Marble Falls from Leander and stopped for coffee and apple pie at the Bluebonnet Cafe.

I just did the 22 cent mod. (Thank you DaveC for those washers!) I started conservatively with only one washer/shim on the needle since I have not modified the exhaust or the airbox, yet. Drilled the slide and found the pilot valve was already about one turn out. I moved it another half turn out from that.
And as previously mentioned, I seemed to have some success last week, pulling the carb and cleaning the heck out of the bowl and floats.
So today, no stuttering whatsoever. And what I thought was cool, is some new behavior and sensations... Like, before as one example, if I throttled hard going up a hill, the bike would tend to knock. It would accelerate conservatively, and it would usually knock a bit. Now, I hear a nice barking exhaust note, and the bike pulls up the hill with confidence. It felt great!
The bike feels stronger whenever I roll on the throttle, so I don't know what was off with the carb, but apparently something wasn't exactly right, until now!
This was also the first slightly longer ride since I removed the Conti TKC 80s and put on Shinko 705s. There's a lot of good to be said for those TKC 80s, but for the kind of riding I do most of the time, they weren't really appropriate. As the TKC 80s started to get a little scalloped on the front, I'd get some pretty scary shimmying at freeway speeds and on fast cornering. Didn't like it. The 705s are like night and day, maybe partly because I had them balanced. There was no shimmy and they rolled in and out of the curves great today.

Also, since I've had the bike, there's been a couple of times where my ammo can panniers caught my leg just a little when I put my foot down and I started wondering if they were a busted ankle waiting to happen. So, I pulled them off. I'll get some soft panniers when I need them. I liked the look and utility of the cans but those rascals along with the bracket weighed almost 40 lbs!

Okay, I'm done rambling :thumb:

IMG_0744.jpg


IMG_0742.jpg


IMG_0741.jpg
 
wanabeguru said:
Fingers crossed for ya!
Click to expand...

Thanks wanabeguru! Had another good ride today! Did a 85 mile round trip to Inks Lake State Park from Leander.
My wife would have preferred I stay home and paint the house but I really need to get out once in awhile. Gotta work all week... I can get a little peevish if I don't get any ride time. I came back in time to help her for awhile just before it got dark at least and that seemed to appease her... phew

The bike performed flawlessly again so I reckon I can put this thread to rest now. Really thankful for all the support and ideas from everyone. It would be hard to own a bike otherwise.

The Hatchery was closed
IMG_0752.jpg

But the state park was open. They gave me a free pass so I could check out the park.
IMG_0746.jpg
 
DaveC said:
:ponder:
A KLR guru in the making?


:mrgreen:
Click to expand...

Sheesh... I guess there is an upside to having various problems in life. I have ended up knowing all kinds of things because of computer problems, motorcycle problems, appliance problems, etc. Builds character :eek2:
 
Thank you guys so much for this excellent thread! This is the most detailed and systematic record that I have found anywhere of someone trying to find the root cause for the same issues that i am running into. Looks like I'll be tearing into her...again....right before I was planning on leaving. I'd rather do it at home than out on the TAT. Uuuggghhh!! 🤣
 
thejohnnyutah said:
Thank you guys so much for this excellent thread! This is the most detailed and systematic record that I have found anywhere of someone trying to find the root cause for the same issues that i am running into. Looks like I'll be tearing into her...again....right before I was planning on leaving. I'd rather do it at home than out on the TAT. Uuuggghhh!! 🤣
Click to expand...
Post back up your findings here or on the KLR thread.
www.twtex.com

KLR650 Thread

Conroe area here looking for more KLR riders in the area.
www.twtex.com www.twtex.com
 
Have fun on the TAT and be careful.
 
thejohnnyutah said:
Thanks! I will be!
Click to expand...
I will say for the kind of ride you're wanting to do I would put a manual petcock valve on and not worry about that. You can also get a pulsing if your chain has too much slack in it. jelly if you have that you'll be fine under acceleration but fixed RPM and slowing down you'll feel the pulsing
 
I ordered the KLX jetting kit from Eagle Mike. He was extremely helpful (even when I called him at 7am because I forgot about the time zone difference). He was genuinely interested in helping me to get the right parts on my MC, not in trying to sell me as much as he possible could.
I decided that I was going to take out the carb the night before so that I could start the install and test run early in the morning. While doing this, I just happened to put my hand on one of the acorn nuts on the exhaust manifold and... it moved. 🤔 I then realized that the other nut was completely missing. Made a run to the hardware store, tightened down the new nuts and... viola! Problem solved. 🤣🤣🤣
I did go ahead and remove /clean /re-jet and adjust curb idle and remove the snorkel on the air box. The bike runs better now than it ever has!
Thanks for all the info and I hope I'll run into some of you out there!
 
Well, I'm just beginning to narrow down the cause of the "stuttering problem" in this KLR... I already swapped my fuel filter for a new one, and I'm not seeing anything there. I used some throttle bore cleaner to make sure the gas cap vent(s) are clear, no problem there. I suspect there's a piece o' crud lodged somewhere in the fuel line, perhaps the petcock is the culprit... I'm not sure whether this is the original petcock, as the previous owner put an aftermarket fuel tank on the bike. So that's one suspect area, the next will be the carb, which may very well have a gunked-up jet or needle. I may bite the bullet and start tearing into it manana... 🤔

I took the bike for a check ride yesterday, fiddling with the fuel mixture screw every so often, but I couldn't eliminate the stuttering. The problem was most evident in high gear or at high(er) RPMs, but it seemed to rear its ugly head in lower gear too, after I messed with that screw a bit. I reckon I'll start tearing into the bike tomorrow, gonna watch championship football today, aye? Once I remove the seat, I can also access the air filter and clean it, though I don't think that's the problem. Petcock or carb, those are my two greatest suspects in this stuttering scenario... hopefully I find a large piece o' crud lodged somewhere in the petcock, lol. 😬

Of course, I'll probably tear into the carb anyway, just to make sure there's nothing glaringly wrong with it... I'll buy a carb kit if necessary, I can't afford to pay somebody else to rebuild the carb at this time, and I usually do all the work on my vehicles anyway, since I'm mechanically-inclined and I like tinkering with motors. Got plenty of tools too, so no worries. The stuttering problem is just another slight headache at a time when I didn't really need it, lol. Meh, such is life, I'll sort it all out pronto... but right now I'm already locked into the countdown for the first championship football game, I think it's Chiefs-Ravens for the first match (AFC Championship game). 🏈
 
My first suspect would be the vacuum petcock valve or the vacuum line that activates it. I have had similar problems in years past before I went to a straight mechanical petcock.

After that I would probably bet you need to go through the carburetor. If you have access to a ultrasonic cleaner or can get one. It will make cleaning that carb a breeze.
 
ntklr650 said:
My first suspect would be the vacuum petcock valve or the vacuum line that activates it. I have had similar problems in years past before I went to a straight mechanical petcock.

After that I would probably bet you need to go through the carburetor. If you have access to a ultrasonic cleaner or can get one. It will make cleaning that carb a breeze.
Click to expand...
Step one on a carb'd KLR... throw the stock petcock in the trash.... Step two, the "T" vacuum hose mod...

Then... a good carb cleaning and a $0.22 mod while putting things back together usually cures any fueling woes that they can have.
 
Yeah, my next step is to pull the petcock, which has had a very slight intermittent leak as well... probably enough to mess things up, I reckon. It doesn't happen very often, and it's just a drop of fuel that gets lost as I turn the petcock off or on, but I don't like the leakage. This ain't no British bike, goldurnit! Wait, the British bikes usually leak oil, lol. Maybe I'd be better off with an old Triumph or a Norton Commando... my brother who used to live in England, rest his dear departed soul, he had a nice collection of old British bikes, including an old Vincent which must have been worth a fortune from a collector's standpoint. Triumph, Norton, BSA, Vincent... all those makes were represented in his collection. Dunno if the family over there still has the bikes, haven't heard anything about 'em lately. 😕
 
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