Surging problem?

Hey guys :thumbsup:

My KLX starts with like two kicks when bone cold so it starts great.

My problem is when I ride and I lock the throttle in one position the bike surges\hesitates as if I'm moving the throttle back and forth when I am not moving at all.

Any idea what I should look at? I don't know that much bout these things, learning as I go! I tried to do a search but I couldn't find much information.

Thanks!

Check your cables. May be one or both of your throttle cables is binding or kinked. Especially if it only does it when riding and not at idle. good luck

Hello!

Thanks for reply, when I pull the throttle and let it go it snaps back nice and crisp, but I will try to check them for binding and stuff when I get home, I probably need to lube them but the cable luber I have the dang throttle\clutch cables are way smaller then the luber hole haha. but I digress.

Also, the KLX tends to randomly stall. Like once it stalled when I pulled in the clutch and jammed on the back break, the other time I was just waiting for a car to go by.

it doesn't seem to very in throttle much while sitting at idle tho when I'm just letting it warm up, at least not noticeable by me!

Thanks for advice I will check out cables soon as I get home from work (nights boo hiss)

Check your cables. May be one or both of your throttle cables is binding or kinked. Especially if it only does it when riding and not at idle. good luck

Does the surging only happen at constant throttle positions? If so is it all throttle positions or just around a certain position. Put some tape or white out on the grip and the Cam to mark off 0, 1/4, 1/2, 3/4 and full throttle. Maybe then you can narrow it down to a certain throttle position. It kinda sounds like it is lean surging but try to find out where it is doing it and then go from there. Is the bike rejetted? Is the hot start cable getting pulled?

I'm gonna chalk it up to jetting. If you haven't rejetted yet...you should...it'll clean up all your jetting circuits and give you a good base jetting to work from.

Sounds to me like your jetting is to rich and your loading up. My old yz did that cause the previous owner put a 190 jet in it instead of a 175 like it was supossed to have.

Hey Guys:

Little history I guess then , I got the bike it's an 08 from the stealership as a demo used model. I never tested it (cept to see if it ran) as it was winter, and I installed all hte upgrades I read off the forum before I ever drove it, so not sure how it was stock.

Upgrades: AIS Block off, smog bypass, FMF header, FMFQ4, New air filter (TwinAir) and JD Jet kit.

Red needle 3rd clip (10C and up)

170 Main Jet

I'm around 1200-1500 above sea level.

I ride anywhre from 8C-28C

Pilot is not stock, it is richer then stock. I cannot remmeber off hand, I wanna say 78 that sound right? I would hvae to look again! It came that way. I have the stock pilot tho in a bag.

I put that medium O ring on the spring as per JD.

The bike will start with like second kick after a week of sitting with no choke. And the first couple times I goose the throttle black smoke will come out.

As for the throttle, I will admit I moved up from a DRZ (and I bearly drove that as it shoulda) so this bike scares the shit out of me.

Thus, I have prolly never went higher then half throttle and 2nd gear at best. so most of my riding has been under half throttle for sure so far as I get used to her.

When im riding on the road is when I notice the surging most, so Im putting along in second gear maybe 1/4th throttle def less then half throttle.

I am off tomorrow so I can get into her and start chking out what you guys have all recommended! Last night shift!

It sounds like the pilot jet to me. Swap the pilot that is in there for the stock size and give that a try. The stocker should get you pretty close.

thanks for the advice, Soon as I wake up tomorrow I will try to swap the pilot for the stock one! Also I think I will buy a new spark plug, I never changed it out who knows how old it is, can't hurt neway.

I'll let ya know!

Hey Guys:

Little history I guess then , I got the bike it's an 08 from the stealership as a demo used model. I never tested it (cept to see if it ran) as it was winter, and I installed all hte upgrades I read off the forum before I ever drove it, so not sure how it was stock.

Upgrades: AIS Block off, smog bypass, FMF header, FMFQ4, New air filter (TwinAir) and JD Jet kit.

Red needle 3rd clip (10C and up)

170 Main Jet

I'm around 1200-1500 above sea level.

I ride anywhre from 8C-28C

Pilot is not stock, it is richer then stock. I cannot remmeber off hand, I wanna say 78 that sound right? I would hvae to look again! It came that way. I have the stock pilot tho in a bag.

I put that medium O ring on the spring as per JD.

The bike will start with like second kick after a week of sitting with no choke. And the first couple times I goose the throttle black smoke will come out.

As for the throttle, I will admit I moved up from a DRZ (and I bearly drove that as it shoulda) so this bike scares the shit out of me.

Thus, I have prolly never went higher then half throttle and 2nd gear at best. so most of my riding has been under half throttle for sure so far as I get used to her.

When im riding on the road is when I notice the surging most, so Im putting along in second gear maybe 1/4th throttle def less then half throttle.

I am off tomorrow so I can get into her and start chking out what you guys have all recommended! Last night shift!

You're rich. If you are running a 170 main, and a 48 pilot...that is even rich for sea-level on this bike. Try a 155-160 main and look then to the pilot and think about leaning it a bit...maybe 45...then a 42 if 45 was no better. Fuel screw is 2-2.5 turns out? I run a 155 main and a 42 pilot at sealevel but as others have found, the jetting on this bike differs from bike to bike even at the same elevation...humidity seems to play alot. (ie: california sea-level vs. BC sealevel)

Keep us posted and good luck

Hey Dirk, thanks for the advice.

I believe I am 2 turns out on the a\f screw (I pretty much carbon copied the JD kit instructions) it did say use a 160 main I believe, then it said if you changed the exhaust to start with the 170.

So reading here on the forum, I should change out my main jet as you advised, then warm the bike up, then set the idle to just bearly running smooth, then start turning down my A\F screw until it stalls, if I can screw it all the way in I need to go leener on my pilot, if I go more then 3 turns out I gotta rich the pilot eh to fine tune it?

How do I know if I am to lean when I start messing wtih the jets?

Hey Dirk, thanks for the advice.

I believe I am 2 turns out on the a\f screw (I pretty much carbon copied the JD kit instructions) it did say use a 160 main I believe, then it said if you changed the exhaust to start with the 170.

So reading here on the forum, I should change out my main jet as you advised, then warm the bike up, then set the idle to just bearly running smooth, then start turning down my A\F screw until it stalls, if I can screw it all the way in I need to go leener on my pilot, if I go more then 3 turns out I gotta rich the pilot eh to fine tune it?

How do I know if I am to lean when I start messing wtih the jets?

Priority one is to get it warm and then start the process you have outlined. You don't need the main circuit at all...leave that til last...make sure the needle is in the correct position for your altitude and then confirm pilot circuit. After that its all easy street. If done correctly, your fuel screw should make a noticable difference if you turn it more than 1-1.5 turns in any direction. Once pilot is correct the main is all about personal preference...you want to be rich enough to run cool but lean enough to get the most power out of it without going too lean and running hot.

Hey Dirk, thanks for that clearification.

one thing I'm always super afraid of is after warming it up going around the block, will I over heat it while fooling around with the idle and A\F combo to verify the pilot circuit?

I mean I know people do this so it might be a baseless fear. But like, do you play fo ra minute, then turn the bike off?

Once you get your pilot circuit verified, how do you know if your bike is running to hot? DO you just rip around your normal riding style and feel if the bike has enough power with out boiling over? hehe.

seems kinda black magicish?

Hey Dirk, thanks for that clearification.

one thing I'm always super afraid of is after warming it up going around the block, will I over heat it while fooling around with the idle and A\F combo to verify the pilot circuit?

I mean I know people do this so it might be a baseless fear. But like, do you play fo ra minute, then turn the bike off?

Once you get your pilot circuit verified, how do you know if your bike is running to hot? DO you just rip around your normal riding style and feel if the bike has enough power with out boiling over? hehe.

seems kinda black magicish?

Take the bike for a rip...keep wind through the rads if you're stressin it...just make sure you are up to operating temp...5-10 mins of regular riding...make sure the bike idles well...then start closing the fuel screw...follow the procedure and you're gravy...it'll only take a minute to perform the fuel screw check. Once your pilot is confirmed you can start in on the main. It will take a couple attempts i'm sure but try different mains...see what feels best when you crack er open. If it is too rich it will fall off up top. You won't need to worry about too lean as long as you stay stock or larger. i would try a 150-155 at your altitude but maybe someone from Alberta will chime in...KMAX? anyone.

Thanks for the advice, lookin' forward to working on it tomorrow see if I cannot dial it in a bit better ! you guys are awesome.

Stupid question tho, what do you mean by it will fall off up top. ?

Considering ive never put it to WOT and doubt I have the balls or skill to do that hahah. what would be considered up top? and what is fall off.

thanks!

Thanks for the advice, lookin' forward to working on it tomorrow see if I cannot dial it in a bit better ! you guys are awesome.

Stupid question tho, what do you mean by it will fall off up top. ?

Considering ive never put it to WOT and doubt I have the balls or skill to do that hahah. what would be considered up top? and what is fall off.

thanks!

What DIRK means by "fall off" is at your upper RPM range [in any gear] you'll feel a very noticable power hesitation; almost like a stumble. Coming up to that point, you'll feel an increase in power, torque until you hit the "point" where your not burning the fuel you're feeding into your carb and you'll begin to feel the hesitation I mentioned. Hey DIRK, good explaination above :thumbsup:

Busted her open today and realized a couple mistakes.

I said I was red needle 3rd poss. I'm actually Red Needle 4th Pos as per instructions 0-2000feet.

The pilot is a 48, the stock is a 45 (which I have)

Are you able to change the pilot with out taking the carb out? is there a trick, I hate taking this carb out lol.

Hopefully by end of day I can have her runnin right, thnx for all the advice so far!

Busted her open today and realized a couple mistakes.

I said I was red needle 3rd poss. I'm actually Red Needle 4th Pos as per instructions 0-2000feet.

The pilot is a 48, the stock is a 45 (which I have)

Are you able to change the pilot with out taking the carb out? is there a trick, I hate taking this carb out lol.

Hopefully by end of day I can have her runnin right, thnx for all the advice so far!

You CAN do it but it is easier to just remove the carb and be done with it. Good luck.

Got the carb off, changed the pilot jet, couldn't get the carb back on haha.

That damn metal clip keeps getting pulled off by the suspension and making my life annoying! After like two hours I gave up and took my street bike out hahaha.

Hopefully finish it tomorrow :thumbsup:

Ya that damn metal clamp is the worst part of getting the carb back in lol and if you dont get it right and get sand in your motor your screwed. just peak behind the header and shock and make sure its seated right

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