Mech

Yeah it's often difficult to get the exact right manual, but generally a manual for a close model will do for most things. Sometimes the only difference is in the colour of the body work, or the carburetor, or the wiring because the other model has day-time running lights or no brake lights or some minor detail like that. If you look up atv parts on Babbits parts, you can choose each of the different models for your year, and browse through the pictures in the first page each model presents, and look for the things that are different to your model. https://www.babbittsonline.com/oemparts/c/yamaha_atv_2006/parts

Have you looked at the parts drawings ? That bevel gear on the outside is on a shaft that only has one big gear on it. I'd imagine there is meant to be a tiny amount of play between the two bevel gears that turn the output from chain drive to shaft drive, and then there will be noticable play between the big gear and the other big gear it engages with. I'd check for that play first. If there is no play at all then it's something with the two bevel gears(or bearings), or that first shaft with a gear on.

Ok, that's good. You should be able to feel that you are getting different gears because each higher gear gets slightly harder to rotate the shaft. If you have all the gears then we need to find what's gone wrong with the shift lever's shaft's connection to the shift shaft that comes out at the front. In this picture you can see how the shift lever shaft( 9 ), and arm (15), are meant to engage with shift shaft ( 17 ). If the arm 15 has come disconnected then you will have to try turning each shaft and try to get them to re-engage. Hopefully once they are engaged they will both move together. If they are already engaged, but jammed up so they won't move, then you are going to need to take the rear cover off think, but before that I'd spend a bit of time trying pushing both shafts length ways, even though I don't think either are designed to move length ways, and try rotaating them both so they do disconnect and then try re connecting them. If the shift arm 15 is engaged properly it will move shift shaft 17 both directions with very little lost movement. So.. recheck that the start washer is in fact getting every gear, then get the shift lever shaft and shift shaft working.. Then we can worry about why the electrical shift is working or not.. I suspect that once we have un-jammed the shift shafts the electric will work fine.

Ok.. so, if the drive shaft has a little movement at the engine then the bevel gears are probably ok, but if there is absolutely no movement then it's possible the bevel gear is broken. If there is a bit of backlash play between the bevel gears but then solid I'd guess it's the final drive..

Yeah that's a good sign.. It must be stuck in two gears, and as long as it hasn't damaged the gears it should be reasonably easy.. we hope. I haven't seen one of those. In the KQs there is the regular five speed box, and then that drives the reduction gears. The reduction gears are great big chunky things. If the five speed box had stuck in two gears, which is virtually impossible anyway, then you'd be able to slip the bigger reduction gears in and out still I think. So.. if it is the same layout(parts picture), it will be the reguction gears, or reverse that's somehow managed to engage two gears at once, which will be in the shift mechanism and interlock if it's reverse. Those parts, the shift mechanism etc, should be in the side case. I'll go have a look in a parts diagram..

The leak down of the compression tester might just be the shraeder(sp) valve.. You connect a vacuum gauge to the inlet manifold. It tells you pretty much as much as a compression test, and a bit more. We check the idle vacuum, the light throttle vacuum, take note if it's steady or fluctuating, One a multi cylinder it is a bit more accurate and simple to read, but on a single cylinder we clamp or restrict the hose so it doesn't fluctuate all the time because of the single pulsing vacuum.. Good compression has about sixteen inches of vacuum minimum, less and there's an inlet leak or low compression, but when we give it a bit of throttle the leak becomes insignificant and so the vacuum should come up to a normal revving engine vacuum of about nineteen inches of vacuum, if it's still low at a few revs then it's compression. If it's got a tight inlet valve then they get real fluctuaty.. fit to break your gauge..haha..

Nope.. sounds like you're on to it. Check the oil for metal perhaps ? Gearbox metal.

If it's the shaft the plate clutch normally fits on is moving in and out it's because the clutch is off it now. It needs pulling out, and the gears won't work if it's pushed back. Pull it forwards and turn that as you try turning the star washer, with the roller pressing on it. It will take a bit of force to turn it with the roller pressing it, and you need to rotate that shaft at the same time.. If you do that you should get five gears and a neutral. Even if the wheels don't turn, you should feel the difference in resistance between first and top gears, and perhaps be able to see the other gear box shaft rotating in a bearing. Get that right first. There's no point worrying about the more external linkages if the actual gears inside need stripping down. Make sure the star washer can get all the gears first. Then we can concentrate on fixing the change linkages. And the first step in checking the change linkages I think is make sure it's not the reverse interlock causing it. We need to get that manual shift lever working that change shaft that pokes out the front now, the one with that shift mechanism on it.

It's possible that the shift shaft has moved back now the shift mechanism is off it. It might need pulling forwards to re-engage with the shift lever's shaft. If you look in a parts places picture you will see how they fit together. I doubt there's anything wrong deep in the middle cases, which is where the gears themselves are. You need to retry the shift barrel and star thing, leaving the detent roller engaged with the star. You should be able to get all the gears and neutral. If you can get the gears(at the star wheel), then we can concentrate on getting the manual lever to work them, then figure what's gone wrong ..

Accuracy isn't so important. We can tell a lot about the condition of the motor by how fast the pressure comes up as we wind it over, and whether it improves with a bit of oil down the bore. Another tool that's just as useful is a good vacuum gauge. My gauge is big and old and made of brass.. It came form a dairy/milking shed... If you're looking for a vacuum gauge.. dairy shed supply places would be the place to look.

Hi. Yes you have a YFM450 and the specific model for parts or working in the service manual is the FAV.. You should be able to find a service manual in here that says it covers the FAV model.. The graunch into gear might be because the engine is idling too fast. That's pretty much the most common cause of it. It needs to be idling away at a nice slow pace. You should also check the clutch adjustment. There are two separate clutches in the quad, one is a centrifugal one and that locks up with revs to start the bike moving automatically. The other clutch is a plate clutch and it's operated by the same lever as shifts the gears. It's job is to stop gears crashing when we do gear changes at revs above the centrifugal clutch's lock up revs. The plate clutch needs adjusting from time to time.

Yes that second idle discharge hole is very important. It starts off diluting the mixture when it's idling, but then turns into a discharge port enriching the mixture as soon as the throttle is opened a little amount. It's an important part of the acceleration process and if it's not right, or if the throttle is too far open when you adjust the idle mixture, it will cause flat spots. It's not a good idea to use welding tip cleaners though.. that initial resistance you felt Oldguy, may have been aluminum being chewed away.. and we really don't want to enlarge that hole..

Yeah that's weird. I'd have not picked that given the symptoms.. spark when pulling by hand. Perhaps there is some play that allows the crank to move enough to rub, when the starter is operating.. but not move with the pull start. I think I'd be checking the main bearings for play..

Here's what I have.... output.pdf

I just realised the shift motor is on the front, and will already be off.. It has to be in the rear case where the two shafts come together at right angles, or, the reverse interlock is causing a problem.. Pretty sure.

Morning Hoss (well it is here), welcome along. I'm sure you will find a lot of good advice and useful information here.. There are owner manuals, and service/workshop manuals.. always a good place to start with a new bike..

Is there some particular breather tube that's troubling you Blasiri ? I can try to find and describe where things go by looking at the diagrams.. But not for every hose.

The shift problem is looking like being in the rear cover, which I think can be taken off in place.. I wouldn't rush to do that just yet though. If the gear shift shaft that comes out down near the star washer won't move, then it's something in the back, the lever that goes between the manual shift and the shift shaft, or the electric motor, or perhaps something to do with the reverse interlock. I'd try taking the reverse interlock cable off, and the electric motor off, and then try moving things by hand trying to figure what's happening, and what's not happening as it should. I'd hold the manual shift lever and the shift shaft at the front and check they were interconnected and operating correctly. If you look in the online parts places at the gearshift picture, you will see there's a short shaft and link operating that longer shift shaft that comes out the front. Try and figure whether those two shafts and links are connected together and working. Take off the electric shift motor and see if things move then.

I thought getting quad tyres off was the mission.. never had trouble getting them to go back on. I just push them down onto one side of the rim, then lift the tyre enough that it closes the gap at the top while I inflate it.. Old distorted tyres though.. yeah sometimes a rope around the circumference works, if it's tightened just the right amount. Slime.. I love it. We have lots of scottish gorse here, it grows like a weed and huge and drops prickles that will go through a quad tyre. I got sick of fixing slow leaks years ago and fill every tyre with slime these days as a preventative.. in my new tubes even.

That was a good learning experience then.. haha. Glad you got it sorted.. and fessed up.. haha.. Onya.

Excellent.. Things like the fan not behaving, even though we know the wiring isn't all attached, can lead us on a merry run around alright.. Like trying to run/fix things on jury rigged fuel tanks, only to eventually discover they need fuel pressure. It's always a problem though when we start on something unknown and just want to ascertain it's viability first.. Well done on finding the pragmatic way through..

I probably don't have any other pictures.. I'm a bit short of time today as well, but if I get a chance I will have a look.. But the explanation's going to be longer than you finding the info in a diagram... Sometimes you have to look carefully at the grey parts of the diagram as well as the vivid parts the drawing is showing.. Sometimes when you look at the plan view then the side view, it all becomes clear.. I bet once you have it back together, it will all look just like in the diagrams..

Yup it could be a bad earth with the starter issue, but I think since it won't start with the battery connected and using the pull start it will be wrong wiring into the cdi unit or the wrong cdi unit. Have you had it long Faroe ? What's the history of this issue ?

Ok, So we might have two issues here. We've ascertained that the shift barrel rotates, and so should be changing gears, but doesn't seem to have any drive, and the manual shift lever still can't move.. is that correct ? I think we should check whether the gears inside the case are moving and engaging first. That star shaped washer and it's sprung loaded roller that you were holding back are what set the shift barrel's position. Between positions there are neutrals, no gears engage. It has to be like that or you'd get two gears for a moment as you shifted. What happens is, as you move the shift lever up or down, it rotates that start washer and lifts the sprung loaded roller till it gets to the top of the star's bump, then the star washer and shift barrel rotate under the pressure of the roller and shift the rest of the distance into the next gear. It's that roller that engages and holds gears. You need to test the gears again but this time leave the roller pressing on the star washer. You will notice that the star has a smaller hollow which is the neutral position. Test to see that each gear seems to shift and be engaged, even if it's only checking they have some small resistance to turning.. If we are sure they are engaging and turning the second shaft then we will worry about why the tyres aren't turning. Perhaps a H/L neutral ? Or is this a super low first model ? I'll look in the book later if I get a chance.. Since the gears were working though, just no shift, I wouldn't worry too much about that part of it at the moment. If you do think the gears are bust, look for metal flakes or chunks in the sump.. use a magnet.. If we can get the gears working, we need to figure out what's gone wrong and jambing the shift lever. I think the first thing there would be to try and remove the electric shift motor. I'd suspect that if the electric motor seized it might jamb the manual shift as well.. But I haven't looked in the book yet..

Good one Have fun..