Question for 2 stroke fans......

Shouted the 500 triple an "Ivans Jet Kit".

As most triple owners know the carbs for these are pretty simple and not much can go wrong.

But....
I have one troublesome carb that no matter which cylinder I put it on,it doesn't fire and the corresponding header pipe is cold.
So therefore have taken electrickery out of the equation.

The carb in question is super clean and float has been set to the correct level @ 25mm.

Struggling to come to grips with this problem and have no answers.

Any help would be appreciated .....

Given that it is specifically isolated to one carb and the misfire transfers if you swap carbs over and the fact you have checked both the float level and also wear on the needle and the seat, then it can really only be a blocked carby. Are you sure all the jets are free? Recheck the carb in it's entirety and make sure fuel is able to flow through. It can only be a fuel issue it transfers from cylinder to cylinder. If it were only one cylinder, then you might check compression etc., but being that it stays on that carb it has to be a fuel blockage somewhere........... Good luck, finicky issues suck.

That's the reasoning I can come up with as well Strika.

Ive become a master at removing cleaning and refitting the carbs

Gos may have some answers?

Hi Dave - Strika has hit the nail on the head I think ? if you have tried this carbie on all 3 pots and the problem follows it around.....it has to be the carb.

Last time I saw a problem like this it was the pilot jet. Looked clean enough when you held it up to a light source - you could see light through the jet - but it was still blocked. Needed a decent tub with carbie cleaner and then a good blast of compressed air.

How about the carb slide - is it in the right way around ? These are easy to drop in backwards.......

test for fuel flow by taking off the float bowl on the dud carb, fit it up normally then turn on the fuel - this is a good test for the needle & seat. If fuel flows in without issue - it has to be the low-speed circuits - idle mixture and pilot jet.

Does the choke actuate properly on this carb ? Need to suss this out as well, if this has an air-leak it could cause issues....

Good luck with it mate, let us know how you go.

Can't be an air leak Gos. It's not firing at all. If it were an air leak, it would still fire, just run very lean and nip up rapidly. I still think you're spot on saying the Pilot/Idle jet is still got something blocking it. Kawadave, nip over to Gos' place one Sunday morning. He'll have is jet blower going then. It's food and bourbon fuelled though, so take you're gas mask. But...it will clean out ANYTHING from a pilot jet!

I've already hit the nail on the head Gos...the fucken carb will be next thing to get hit on head...

The pilot..needle and main jets are brand new from Ivan.http://www.ivansperformanceproducts.com/h1.htm

I've cleaned the carb religiously and used hurricane force compressed air.

The carb slide has a key-way...so can only be fitted one way.

Have swapped over components from carb to carb only to find the same result.

The choke works fine and has a cable for each individual carbie.

Will try the fuel flow test as suggested, but feel this is all good....are well back to the drawing board.

Has the cylinder connected to the dud carb been getting any heat at all into it??? Choke slides,where the cable hooks up to, in the top of the carb,are they moving freely??Can be a bit cantankerous those buggers.

My own next move after a fuel flow check.....boil the stripped as far as possible carb in rolling boiling water for a good ten minutes. Give it all a really good compressed air blow when cool enuf to handle,and clean again with carb clean.Next,ultrasonic cleaning.

After that , back to the KTOG.

Stu....wherever the dud carb is placed you can put your hand on the header pipe after a few minutes and its dead cold....its also not popping like the others are.

Every time I've swapped the carbs I've used the corresponding fuel lines and choke fittings...ie 1 2 3 etc.

It defo sounds like a blockage...even the KTOG boys are stumped on this one.

I haven't used stuff from Ivan's before - but his site looks pretty good ! Some excellent bits there......

Marty - the leak in the choke I was thinking of, would stop the choke working - which could cause cold-start issues on that particular carbie ? Not so much an air-leak at the manifold which would lean things out as you say.........and yeh the bourbon-fueled talking arse talks in 5 octaves now !!

Dave - what does the plug look like in the dud cylinder ? Always dry ? There has to be some type of blockage, these carbs are pretty simple .......I can't think of anything else ? I have some OEM H2 carbs but these are 30mm and too big for your stock inlet manifolds......

Dave - what does the plug look like in the dud cylinder ? Always dry ? There has to be some type of blockage, these carbs are pretty simple .......I can't think of anything else ?

Gos...as you know I'm using iridium plugs...tried swapping them also...but generally slightly wet on the dud carb.

slightly wet......hmmm there must be some fuel getting in there ??

Have you tried cracking a bit of StartYaBastard up the guts of the dud carbie (with throttle full open) - then trying to start the bike ?

No I haven't mate...the bike starts, runs and idles...but its just not firing wherever the dud carb is.
Worth a try I guess.

it must have a lumpy idle ? How easy does it start ? Normally if 1 cylinder is down on the triples, they can be a bitch to start and don't idle well at all......and riding them is difficult as they just don't pull cleanly ??

Surprisingly enough it starts easy and idles well.
But when I took it for a test ride it was boggin down badly at low to mid revs....which also suggests it is a pilot jet problem,yes?

Daves and Stu, KD says the plug is wet. So, perhaps it's not a fuel blockage at all?? Could it be a shitty needle on the float valve, or a shitty float which is flooding that cylinder? Have you tried sticking a fresh plug into the cylinder which is wet and doing a WOT start to see if it fires? As Gos suggests, perhaps some SYB to help get it going and then see what happens. If it fires at WOT then it might be a worn float flooding the cylinder.

Or, as Gos says, the choke circuit might be screwed? However, you said you rode it, so I assume you had backed of the choke by then??

Yours truly
Confused