Mech

I was referring to your first and second gears.. If you put that chipped bit on the first pictured gear, it would look right, a cast finish... I wouldn't try taking that motor apart and getting it back together in one day Chris, not if I was doing it, it's rushing too much and will probably lead to problems. I'd figure on about two hours to strip it, then another two to inspect everything and give things a preliminary clean and make a parts list, then another five or six hours to put it all back together again carefully. Your mate is mighty ambitious.

The numbers were referring to the picture in that link. The gear with splines in the middle is third drive gear and the one without splines is third driven gear. The dogs are those bits which stick up, the bit that got chipped off the old gear is a dog. That chipped off dog must have come off the third drive gear since it has a cast finish on the little bit at the center/bottom of it.

That chipped off dog you have sitting on the new gear Chris, on the inside edge of it, the bottom of it in that picture, the surface is cast without machining, the gear it's sitting on is machined in that place. It must have come off some other gear or place.

That bottom picture looks like the third driven gear Chris, No9. The top picture I presume has drive dogs underneath it ? In which case it's third drive gear, No3. The missing dog wouldn't necessarily make for hard changing, not unless it was getting jammed somewhere it shouldn't be, which it probably wasn't. It might have got knocked off because of the original problem, which I still suspect is in the clutch. LTZ400 Trans.pdf

I had a read and that is a primer pump for extreme cold. If the float level is set correctly the fuel shouldn't get to or leak out of the top of the bowl. If it's idling and the fuel is getting shaken up then there might be some small amount of fuel getting to the top, but it should hardly cause any leak, just a bit of wetness. I'd take the bowl off and recheck the float operation and level. I'd inspect the rubber seal isn't too flat and if it's still reasonably round in cross section I'd try using it again. If the leak is bad, you've probably not got it located in it's groove properly allowing the bowl to be held away from the carb body. If you've tightened the screws real hard trying to stop the leak you may have distorted the bowl. Give it a quick rub on a bit of wet and dry paper on a flat surface to check it's still flat. Those rubber bowl seals usually last for years, but sometimes if you dismantle the carby and have it apart for a while the rubber distorts and can be hard to get back into place as you put the bowl on. The way to get the bowl on with the rubber seal in the right place is to fit the rubber in place as much as possible, then use a feeler gauge(or two) to press/hold the last bit down into it's groove while you fit the bowl. Once they are refitted in their groove properly, they normally seal even if they are old and hard.

Yeah that's what I'm suspecting too Dave.. The owners manual should describe that if it's the case.

I just noticed you say that it pumps if you pull up on the pump's linkage, so does that mean you have the spring above the diaphragm ? And is the push-rod attached to the diaphragm somehow ? It doesn't look like it's attached in the pictures I've got. In the DR400 that plunger gets pushed down, and the spring is underneath the diaphragm.. In the arctic cat and the DR manuals the spring is shown above the diaphragm in the exploded view, but in the DR description of operation later on it shows the spring as being below the diaphragm, and says the plunger gets pushed down to squirt the fuel. If you put the spring under the diaphragm would the plunger rod perhaps touch the throttle somehow then ?

Oh ok. I haven't seen one like that. It might be that they use the pump on a two wheeler, but don't think they need it on a quad. There is another system built in to serve as an enrichener during acceleration. The pictures in the manual it doesn't look like there's any linkage or anything that your pictures don't have. Does that part you have circled in the last photo move with the throttle does it ? In the manual, there is a diagram and it shows something near screw 29, do you know what that is ? It looks a bit like a linkage. Perhaps just try it and see if it goes ok.. Here's a picture of a carby off a DR400.. perhaps you are meant to have a linkage like this, except the pump plunger is different. That's the nearest I've got to your carby.. similar pump at least !

Yeah it pays to use the coolant recommended by the manufacturer. They know what metals and materials are in your engine, and even how the castings were made makes a difference.

In the manual the carby looks like it's on an angle, and I've seen plenty of bikes that did have it's carby at an angle. I'd guess you need a new rubber seal for between the float bowl and body, or the seal's misplaced/distorted, or the float level is wrong, or the float/bottom cover's distorted. In the pictures it doesn't look like there's anything attached to that part you have circled either.. Are you sure the accelerator pump doesn't work off vacuum? It could be that when it's idling the diaphragm gets sucked down, then when you open the throttle it goes up pumping fuel.. That's a fairly common system.

Oh yeah for sure.. I don't use a chainsaw, even though I've got three of them, but I love riding around on a bike polluting as much as the next man..

Yeah I agree Dave, that is annoying, both for my own convenience and because of the ramifications for the planet. Things might be changing though, my son bought two new screens for his cheapish samsung phone, a touch screen and the display screen, in a kit with tools to do the job, for $24 bucks the other week. And I see that all the parts are available for them, main board, speakers, aerials, vibrators, cases, batteries.. It's a good sign, but consumerism is what is fueling it, they couldn't afford to sell parts that cheap, if there weren't millions of the phones being sold in the first place. I just try to not consume. I've got an old phone, an old laptop, and I don't have any other electronic or electrical equipment other than the solar power controller which provides lights at night. I drive an old car, live in a very simple wooden house I built myself, don't travel or purchase anything I don't really need.. which are food.. clothes once in a while.. and an occasional bottle of bourbon.. haha.. I cut my firewood down and into pieces with a handsaw, do laundry by hand, do all my own maintenance and work on the property, and live a very simple life. We can arrange our lives in such a way we don't have to engage in the rat race. I've been doing it since I was twenty-one and managed to buy land, build a workshop, raise a family, serve my community and enjoy my time doing it. It is, as I see it, all a matter of priorities. People make the superficial, the temporary, the material things, their priority, and in doing so commit themselves to a life trapped in trying to satisfying an endless life of wants. Rant over.. Back to the bike repairs !

And I agree Dave, since the change to digital, and "modes", we are all dinosaurs. Kids now have all been bought up with that concept of modes and multi purpose buttons. They pick up some new device and start button pushing and seem to garner what each press is doing immediately. Me, I get shown and have to be shown or reminded several times before I can remember what they seem to know instinctively.

That's very kind of you to say Dave.. I'm not sure it's correct, but thank you. There are a lot of knowledgeable people in here, as with most subject specific forums. The internet is like tv in the old days, people say it has great potential for good as an educational and connecting tool to unite people. Unfortunately it gets abused and some people use it to spread misinformation, to try to raise disharmony. I appreciate the great opportunity it does offer and like to bring something positive to life and the forums I engage with.. And good work all those people in here that do contribute in a positive way.

ha.. I'm just the one with the most to say.. It's life in the country and no wife..

Yeah I grease the ends of the shafts where the splines are and where the seals run. I'd also put a bit of grease under the nut or washer on the outer end, it'll keep water from getting in and seizing the spllnes into the hub The grease won't worry the oil in the diff, and any MP grease will be fine. . Good idea to grease the shaft(if it's like the older models and a parallel shaft, not a taper) on the ball joint so it comes out next time too. All the bolts holding the body work are good to grease when you have them out, and the bolts in the suspension bushes.

Another thought.. When you have it apart, check the gearchange is centering itself properly, and that the mechanism between the shifter and the clutch is operating correctly and isn't too worn.

The oil won't start causing a problem after fifty yards. It's either not adjusted correctly, or there is some problem that was overlooked when they were overhauling the clutches. The clutch springs might be buggered, the clutch basket might have notches where the plates rub, or the centrifugal clutch drum might be worn out. It's got a lot of new parts, it will probably be something with the workmanship... Better take it apart and have another look I think.

A good engineering supply shop should be able to supply an O ring the right size. O rings come in different diameters and cross-section. Even the tiniest ones fitted to, for instance, the idle mixture screw, are standard sizes. And good for you for finding it. When you put it together do that tilting test to make sure it's closing properly and sealing right off air-tight.

Some old floats were hollow and could get cracks and not float, or not at the right height. That metal washer under the float needle seat might not be sealing. If the surface was made to have a rubber ring it may not seal with the metal washer. It might be changing the float level too. In most carbs the choke plunger is metal, and it has a rubber insert in the end to act as a seal when the choke's closed. And definitely try managing the float level by turning the fuel tap on and off while it's running. Once the carby's full it should run for two minutes before it runs out. Try only opening the tap for a couple of seconds at a time and see if it will run and idle. If it does run pretty ok then, then you do have a float problem.

You really should get a manual. It will guide you through the proper diagnosis process, and give you all the specs you need to verify. Try at "manualslib".. google is your friend. or here.. https://www.manualedereparatie.info/en/categorii/yamaha.html There are lots of places that have manuals for free download.

Is the clutch adjusted correctly ?

Have you checked the float actually does float ? As has been said, you need to be sure the float works and isn't leaking between the float needle seat and carby body. A simple test is to take the carby off and tip it up on it's side while you blow through the fuel inlet, then slowly tilt the carby till it's level and the needle should seal against your blowing. It should actually stop your blowing when the float starts dangling down against the needle, it doesn't have to be totally flat. If you tilt it so the float swings away from the needle, then swing it so the float will be dangling but against the needle, it should stop the flow then. It's a good idea to do that test whenever you've had a carby apart. Sometimes the floats get jammed down by the needle dropping too far. Rare, but it does happen.

If the choke is a plunger type, they only operate when the throttle is closed, or near closed. When the throttle's open they don't have enough vacuum to lift the fuel. I'd pull the plunger and check it's still got it's rubber seat/seal. If you turn the fuel tap off and start it, what does it do ? If you turn the fuel on and off enough to keep the carby just full enough to run, does it still flood ?

I agree that crank seals can cause starting problems, but this thing sounds like a flooding problem. If the seals leak, don't they run lean ? This bike accumulates fuel in the crank. I've diagnosed and fixed leaking crank seals before, but I don't remember flooding being the problem.. Perhaps my memory's no good... Was flooding a symptom when you guys found leaking crank seals ? Whether flooding is or isn't a symptom of seal wear, it would be something to check for hard starting. Have you checked the choke is right off ? Does the choke plunger have it's rubber seat still ? They can also get a distorted bore which buggers up the transfer ports operation.. That makes them hard to start. The way to check that is to pull the cylinder off, take the piston off, take the rings off and slide one down the bore. Then use the piston to push the ring down a little at a time, especially where the transfer ports are, and holding the cylinder up to the light you look for light between the ring and the cylinder wall.