Mech

If you keep an eye on the home page it will turn up there once the mods have approved it.

For some reason it starts with the supplement for 1996, then about a third of the way down it goes to the 1993.. I think your bike will be a 93 design sold in 94..

FWE is 1993..

Ok, closest I've found is for a FW, which it says is a FWE, and it has a supplement for 2006, so it must be close. I'll upload it and you can have a look

That's something I found home-schooling my sons Trackpin. And applied in the workshop. Let them compete, or apply themselves, and win, and it encourages them no end... Especially competing against Dad.. haha. You'll get a lot from working with the young fellah I'm sure.. It's all time put in, and it counts.

Well Kodiak, is it a water or air cooled kodiak,, and does it have a five speed, or a two speed belt drive ? And what differences have you spotted ?

So.. I was trying to find a manual for the 270 because I only have a manual for the 250/300, but I found this picture of the inside of the carb and it looks like that hole by the red arrow is normal on these things.. Weird but true. I also found a reference to some "pair solenoid", which it turns out the 250/300 have, and yours might too. It's not an electrical solenoid but a vacuum operated solenoid, and if it had a diaphragm with a hole in it , it could let too much air in.. MXU300.pdf

I'd just leave the wire clip off if that cures the problem. Lots don't have the clip and work fine.

Not knowing what might have been done is a bit of a bother. First up, have you checked the ignition timing is right ? And is the plug the right heat range ? And, have you checked the exhaust isn't partially blocked, and that there is plenty of fuel getting in past the float needle. Using the drain screw is the simple way to check there is plenty of fuel getting into the carb fast enough. Blocked exhausts manifest at higher revs. If you can attach a vacuum gauge and rev it up the vacuum will fade away if the exhaust is blocked. Then the way forwards is some very careful test riding trying things to ascertain where/confirming the problem is in the carb. So... the idle screw, can you just use a small file or saw to modify a screwdriver ? It's important the idle mixture is set right, and at a minimum throttle setting. There are two idle discharge holes into the venturi and it's important that at idle it's only discharging from the one near the engine, and drawing air in through the second one near the airbox, then as the throttle opens slightly the second hole starts to deliver fuel as well giving a richer mixture to accelerate. That won't be your trouble though if it gets up past about 1/4 throttle before faltering. Then there's another enrichening system for accelerating from about 1/4 to 3/4, that being the drilling the emulsifying tube fits into, and the tiny holes in the side of the tube. At low throttle settings that drilling fills up through the main jet and the fuel goes up over the tiny holes, and then as the slide needle starts to use fuel it draws fuel in through the tiny holes as well as through the main jet, until the fuel level in the drilling lowers and then the emmulsion tube lets air in through the tiny holes making it slightly leaner. Initially though as you open the throttle the raised fuel level works as an acceleration enrichener. Once you are on the upper range of the needle, and the main jet, the fuel is being mixed with the air from the tiny holes. If those tiny holes are too big, then it starts out sucking too much fuel, then goes much too lean, or, if the float level is so low that they never get covered with fuel, then it runs severely lean as soon as the slide needle comes into play. Those two acceleration systems interact with the idle and main fuel and air jets to ensure the mixture is right at steady throttle settings, but richer when we are accelerating. When we are test riding, it's good practice to take note of not only how much throttle causes the problem, but also how long it takes between opening the throttle and the problem to manifest. How it reacts if we ease the throttle off very slightly is a bit of an indicator of what's happening too. If for instance the fuel flow into the carb is restricted, then we can open the throttle and it will run ok(all else being right), till the fuel level drops, and that can take from a few seconds to ten seconds or more depending on the amount of restriction, whereas if it's the emulsion drilling being full of crud and so not holding the right amount of fuel, or, the emulsion tube having being changed with one the wrong diameter(which effects the amount of fuel being held in the drilling), then the problem manifests almost instantly. Perhaps too much information, or more than you really wanted, haha, but you sound pretty onto it and so hopefully that will help you pin-point what's going wrong.. And yeah, if it idles then it won't be a vacuum leak, they manifest bad at idle but have almost no effect at throttle. As far as the ethanol idea goes.. it looks too clean and nice to have been eaten up by that... Not that I'm too familiar with the problem because over here we only put ethanol fuel in things made for it.. which means modern cars and not bikes.

Is the float needle a rubber tipped thing ? They are normally very reliable. Are you sure it's not leaking around the O ring on the seat ? I've seen the O ring be a bit too big and not want to go down into the hole, so it was just sealing against the carb body, which also upset the float height by a heap. New O ring and set right in and it was all right. Good you got the partner mobile.. Let the adventures begin.

If you let us know the suffix I might be able to find you the right manual.. I don't post links because it's good of this site to host the manuals, so I'll grab one and upload it if I can find one. And yeah, when you first get a new old bike it's always a good idea to get it going as cheap as possible and then try it before spending too much on what might be not worth it, or need something more urgently.

Ha.. I know almost nothing about yamahas Kodiak.. I'm a rural mech and have worked on suzuki and honda mainly. I've been working on bikes though for fifty years. What I don't know I can generally research and figure out. If there are any questions ask away. There are plenty of experienced yamaha people watching on I'm sure.

You had it all fitted before, and it was all going except for the clutch plate not being aligned and fitted onto the clutch hubs splines, causing clutch slip. You haven't had the nut off, so the hub can't have moved, only the inner plate with the pillars has moved forwards. The adjuster should be able to accommodate that travel. If the adjuster isn't accomodating that travel, then the whole hub must be too far forwards.. i think. Can you post some pictures ? One at an angle at the front of the nut, and one straight side on showing how the basket teeth align with the centrifugal clutches teeth.

Have you checked the adjuster is right back ?

No that doesn't seem right at all for there to be a hole by that arrow. That should stop fuel being lifter through the idle jet.,, Except.. you say it idles fine !! Does it respond to adjusting the idle mixture ? Does it have a diaphragm on the side of the carb ? That plug is lean alright, but not too lean for a modern machine. If it idles then it won't have an air/vacuum leak. If lifting the slide needle made no difference then it's either a blockage of the fuel, or too much air getting into the mixture. Have you checked the air metering jets at the air-box side of the carb are there ? And have you followed the drillings making sure the big one is going to the main jet ? And have you had that brass tube the main jet screws into out ? And at the top of that brass tube, does it poke out into the venturi ? Some have a separate short tube on top of that tube and if that was missing the main wouldn't discharge right. And.. have you ever had this bike running right, or did you get it not going ? Do you know it's history ?

Nice Gw. It's important to make those moments.

Good that you can get him there at all.. Just let him beat you at a few things and he'll jump at the chance.. Don't let him know you let him beat you but..haha

Ok.. That's a good system then. Often putting the battery in backwards plays havoc with the electronics..

Online parts places(babbits or partzilla) will show you the model options it could be, and there are probably service manuals in this site for free download. It's generally a good idea first to look your bike up in some online parts place and check what exactly your model is known as. They are generally YFM400, then two or three letters. The suffix letters are important if you want the very specific information about your bike. The general YFM400 will do for some things, but the specific suffix lets you know things like the carby model and jetting, the ignition system it uses(because they vary a lot), and any spare parts you might want to buy. Getting the right service manual is important if you want to diagnose or work on the ignition system, the charging, or the carby.

The cdi units and the stators change a lot Case and if you look at the wrong wiring diagram it will send you off on a wild goose chase, same with the carbs.. It's always a good idea to be absolutely sure what exact model you have when diagnosing things. Checking the CDI wiring is a good way to check you do have the right model service manual.

Yeah if it's not meant to have the little wire holding the needle to the float it may be the problem. Pull the needle and blow through the seat to make sure there's nothing up there, then try the needle by itself. It should stop you being able to blow through it with just very little pressure on the needle, the weight of the float should stop you blowing through it..

It sounds like it's got a bit of dirt or fluff under the needle.

Yes the whole needle slides including the spring supported pin at the float end. Most of them you either just have the float resting against the pin, by dangling the float straight down from the pivot, that's with the carb tilted on it's side so the pivot is at the top, or you turn the carb upside down and let the weight of the float rest on the pin. If you let us know what size the bike is I'll check that if you like. Or, there are service manuals on this site for free download. It's probably got a little wire clip that goes onto the float. That's to pull the float down when the float drops. I suppose the new float needle seat did have an O ring on it to seal it into the carb body ?

Can you see that file I posted ? In #2. That tells you how to do it. Sometimes people can't see linked files.. security settings or something.