Cleaned Carb 600 wont stay lit

To anybody that can help.

1st: I cleaned every square mm of the carb, due to sitting long.

2nd: Brand new tank of premium.

What's different: XRS Only Choke Plate.

Fast Forward: I just went past choke, and half choke, to no choke (80 degrees here) and I have the bike firing for two or three revolutions, then it dies. I tweak the air screw and idle adjustment for sometimes better, sometimes worse results, but nothing consistent.

It really seems like a gas problem, like starvation, but the carb is clean, and the gas is flowing out of the fuel line.

My right leg is getting the workout of its life.


In most cases it is a plugged idle circuit (you can't tell by looking). Remove idle jet, squirt carb cleaner up into hole (squirt a lot), blow air up into hole using air compressor. Reassemble, being sure to have the plastic splash guard in its proper position. If the above is too much of a hassle, take it to the dealer and they will do it.

When you say cleaned the carb. Did you remove and clean the jets? Was there alot of varnish inside the carb. when you took it apart? When I clean a carb. I will disassemble it and soak it in a bucket of carb. cleaner for 24 hours. Then I take an air hose and blow out all of the parts. Hope this helps. :thumbsup::thumbsup:

yeah, I soaked the jets, I even blew carb cleaner through the three circuits on the the air side, I disassembled the air cut-off, and cleaned.

I have a five horse-sixty gallon, that cycled a few times while I blew this thing out.

I also put in some other jets I have for high-altitude riding, no change.

Believe me, its really acting like the idle jet is plugged, but its not.

The only new increment is the new choke plate.

I'm stumped.

Fast Forward to this weekend:

I put all new seals in the carb. I found the o-ring that was "missing" for the air screw, but it wasn't, it was in there, but I replaced it with a new one anyway.

I cleaned the carb again, TWICE, and all circuits are clean-really clean.

I put Form-a-Gasket on the intake boot where it mates to the head, just in case there was a leak there.

I half choke, turn the idle all the way to stop, and kick.

Two or Three revolutions and stall.

Turning the air screw does little or nothing to improve.

This bike ran last fall, and had no problems.

This is unbelievable.

Sorry to hear of the latest disappointments. I had hoped the o-ring issue might help, but not. I once reassembled one of these carbs and couldn't figure out what was wrong for some time, then realized I had intalled the float in upside down, and it acted fuel starved. The flat side of the float must be on the bottom. It looks wrong that way, but that is the way it is supposed to be. Just thought I'd mention this as an outside possibility.


I used a caliper to measure from the body to the float (bottomside, Flat), to check the float level (which was perfect).

I guess I'm shopping for a new carb, as I cant really find the problem with this one.

Have you ever heard of the decompression mechanism on the exhaust valve failing?

I dont have a decompression lever-took it off when new, but this other mechanism is pretty buried to check out. I wonder if lack of compression is causing my problem.

I had something similar happen with my KTM. cleaned the carb many, many times before swapping out with a known good one and learned that something was wrong with my carb. I happen to look in my gas can and found a bunch of small rubber pieces. turns out one of them got in my carb and more or less "stuck" to it making removal difficult using carb spray. I never did find the piece, but after cleaning it out a few more times and using a small wire to clean out the orfaces it finally ran like it should.

I wonder if lack of compression is causing my problem.

Check for good compression by operating the kickstarter very slowly (so that the autodeomp doesn't kick in) until you feel compression resistance. You should be able to push the kick start lever with quite a bit of resistance through the compression stroke, if you feel very little resistance, you may have a compression problem. I can't imagine why you would remove the manual decomp lever, it is a very useful item for easy starting under just about all conditions.

The petcock screen would filter out debris-and its clean, plus I have good flow from the tank.

I have compression.

As far as no lever, I learned early on that crashing is not cool, so I rarely drop it, and if I do, one hand is on the clutch, and the other is on the throttle.

If it sits for 10 or more seconds between kicks, the next "start" phase is longer, starts up, rumbles longer, then stalls. The kicks afterward are shorter start-ups. It seems like a starvation thing, like the idle jet siphons down the gas, or is out of the gas.

Is the idle jet stem supposed to be submersed?

I'm going to mess with float level a bit. Tried everything else.

When I had my XR600R I went over a small jump and sucked a piece of crap into the pilot jet it died, but even with the pilot plugged I was able to choke it and get it started and keep the revs up above 1/3 throttle and rode 8 miles home, I had to use a wire to get that crap out air and carb clean wouldn't budge it, but if you can't choke it and rev it up to the midrange circut maybe you have another problem, I would try to see if it runs well above the low speed circut. get a small spray bottle you can spray gas in the carb with the filter boot off, may need 2 people, but it should rev once above 1/3 throttle, be carefull of backfires out the carb, at least you can then verify it runs fine except on the idle circut, or not, good luck

take the bottom off the carb and with the gas on manualy operate the float to see if the needle and seat are working properly. Check for good flow. You allready checked the float level so that leaves the Idle circut. Check the spark plug. if it is dry then definatly starving.

Choked mine with a plastic bag over the filter with the Idle turned way up one time. then took the bag off and had enough gas in it then to start and run with Idle way up. 25 miles back home :thumbsup:


I jumped the main over to a 172 from a 165, and the idle screw is cranked all the way up, and it ran for about 4 seconds (woo-hoo!)

The second kick was less than exciting.

So that said, the main circuit is doing fine.

I also switched the idle jet from a 68 to a 65-but no result there.

The only way it'll run is with the idle screw cranked (Main Jet), which means that there is no gas in the idle circuit.

I left the carb on today (its been off literally 10 times), removed the bowl, jets, float, and air-cut off. Then I fashioned several different tubes to fit my compressor nozzle, and did a round robin assault on all the circuits. By plugging different passages, I was able to hear flow coming out of every passage. I could eat off the inside of that carb!

I should say, that while running, I can gun it, but it sounds like its bogging, and it dies. Naturally, I'll agree with everyone and say the idle circuit is not doing its job to help the bogging.


The Pilot Screw is screwy.

My Honda Shop Manual shows the Pilot Screw,Spring,O Ring, and Washer.

The Microfiche shows Pilot Screw,Spring,Washer,O Ring.

EXARESIX says Pilot Screw, Spring, Washer, O Ring.

Other bikes Have Pilot Screw, Spring, Washer, O Ring.

Does anybody have a working example?


That's totally different than what I've seen-but I'm desperate, I'll try anything.

I doubt that rearranging the needle components will make any difference. There are two easy options though: 1. Take it to a dealer, this can be very educational! 2. Buy a new carb ($275)...I had to do this once for a 600. It is nice to examine a new carb the way is is supposed to be. Just put on your larger jets before installing.

I haven't seen two pilot screw diagrams that are similar, including two that are in the factory shop manual.

Not an option to take it to a dealer, they would just stare at the pulse-charged injection, at a shop rate.

If I were to replace it would be a 41mm pumper-no point in going back now.

It is probably something really stupid-I need a day off to figure it out.

I'm not clear on your symtoms, first off is it a XR600R? Is your problem only with the bike idling? Will it run if you rev it and keep it in the higher rpm range?

XR600. It wont idle, and it bogs when I give it gas, after it does fire. So no, it wont run in the upper rpm range.

Runs 3 or 4 revolutions the first kick, less on the second and third kick.

The carb is clean.

You triggered a memory where my quad would run with a plugged idle circuit, but it backfired alot.

I never had an electrical problem before, but what would let the bike consistently fire on the first kick, but cease on the following revolutions? The firing is just too even to be a short.

Not an option to take it to a dealer, they would just stare at the pulse-charged injection, at a shop rate.


Hmmm...this is the first mention of "pulse-charged injection." Maybe you should run this by Eddie Sisneros on the jetting board. I don't understand exactly what sort of injection this is, but it surely would introduce some other variables in anyone's recommendations.

You live in Phoenix, as I do, and one resource I use here is a guy named Tom Rowland. He is the head mechanic at the Polaris ATV dealership in Cottonwood. He comes to Phoenix three days every week and does free-lance stuff on all makes of bikes. He is very good, and he has worked on turbocharged bikes too. (The Honda to be specific). He might be able to help. Also, I think that the folks at NVH Honda on Cave Creek Rd. would be able to work with it, "Pulse charged" or not. They have never done me wrong, and I think their rates are very reasonable.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now