Mech

Also... the standard test as set out in the manual, testing first engagement revs, and then full lock-up under load revs, should give a good indication of centrifugal clutch wear.. and allow us to deduce if the plates are the culprit.. sometimes.. maybe.. haha If the first engagement revs are right, then the centrifugal clutch shoes are not very worn, and so if we get slippage at and beyond full lockup revs, then we are likely seeing plate slippage. If it's late to start moving at the start of engagement revs though, then we can assume the centrifugal shoes are worn, and if we then get slippage at full lockup and beyond revs it might well be the centrifugal clutch.. but it might be both clutches worn.. The only way to be sure we are replacing the correct clutch is by stripping them and measuring and inspecting..

Actually, there's a better way to test your clutch.. The first bit of movement of the shift lever operates the clutch, and then the gears move. If you change down a gear and keep your toe on the lever you will be holding the clutch in, and if you then let the bike roll down to a lower speed and then rev the engine before letting your toe up, that plate clutch is going to get dropped with the engine revving and it should try to rocket you forwards. If the slippage is caused by a worn out clutch then dumping the clutch like that is going to make it slip badly. If the clutch is good still, and it's only the non-self centering that's the problem , then dumping the clutch like that after a down shift will hopefully make the clutch grab and rocket you forwards as it should. You could try the same technique on a down and an up shift and compare the results to try and decide whether it's a worn clutch, bad linkages, or a bit of both.

Ok, if it's made worse by shifting up but not down then it sort of points to the plate clutch. The shift lever has some linkages that operate the plate clutch. The clutch gets operated before the gears begin to shift, so the first bit of lever movement up or down is only operating the clutch.. If an up shift causes the clutch to slip, but after a downshift the clutch feels fine again, even if you are accelerating in that lower gear after a shift, then I'd say your lever, or the linkages, aren't coming right back to center after an up shift, so the clutch is being held slightly on(slipping). I'd disconnect the shift cable at the box and check it's free and then I'd feel by hand whether the shift lever on the side of the box seems to self center fully after an up shift... Then, if you are sure the upshift is making it bad, and the downshift fixes it(test it by doing a downshift from fifth to forth and then accelerating hard), I'd inspect the internal linkages operating the clutch.. as I was inspecting the plate clutch.

The book I looked in shows the cam cover breather going to the airbox front upper left.

Doh... forgot we were talking yamaha.. haha.. I have no idea where yamaha breathers run.. But the book will tell you.

You'd be best to download the service manual and have a look. The manuals tell us exactly where to route the hoses and cables and wiring.. The engine breather is often connected to the airbox breather, and they both have a branch that runs up and around the range selector panel and then ends in two open hoses up there. And that splined thing on the carby there.. are you sure it's not some sort of sintered metal and actually a breather..

Anyway Valkman, unless the oil you have is totally unsuitable for a wet clutch, which seems unlikely given you use it in your bikes, I think you are going to have to take the side cover off and inspect and measure both clutches. I'd recheck the clutch adjustment first though and perhaps try adjusting it with a bit more play than suggested just to make sure there isn't a bit too much stiffness in the cable or gear change linkages or anything.

Gee you guys. We've had wet clutches for more than a hundred years, and the manufacturers know quite a bit about their design and operation... What do you think we were doing for oils before the jaso standards were set ? We were doing what suzuki and every other bike manufacturer was telling us.. Using a suitable oil. They recommend a suitable oil, but it was never any jaso standard. Now that we have modern cars and modern oils to choose from and a lot more additives than we used to, then sure we need to be careful what we do put in our bikes, but it doesn't mean that only the jaso certified oils are safe. Just because some of you put some sort of car or truck engine oil in your bike and then had a slipping clutch, it doesn't mean we are all going to put the wrong oil in... If we follow the manufacturers recommendations and read the oil's label we will be right.. Old suzuki's do not have to have jaso certified oils in them.. There was no jaso oil spec when they came out... They ran fine for years with common old mineral oils. Please stop insisting that we have to use jaso certified oils.. It's not true. There are heaps of oils out there that are of better quality and imminently suitable, and cheaper, than some of the bike shop oils that have a jaso rating.

So that splined bit is part of the carb ? Very strange and surely not for a hose to go on..

There's different grades and brands of 4T.. The book says... "Use only a high quality detergent IOW/40 motor oi l with an API classification of SF or SG.".

I'd doubt the oil is the problem. The clutches aren't too fussy about the oil as long as it's an engine oil of the correct viscosity. Unfortunately it's really hard to differentiate between the centrifugal clutch and the multiplate clutch when you are trying to diagnose them. You can use the shift lever to slip the plate clutch momentarily as you are accelerating at a rev above centrifugal clutch lockup speed and sometimes they will start slipping bad then, which suggests it is the plate clutch, but it's far from conclusive. If the problem only happens at take off, and then seems fine once the revs are up, it tends to suggest it's the centrifugal, but again it's not conclusive. Luckily the two clutches are both together in the one side case, which can be got off in place, and are components we can inspect and measure once they are apart. That is really the only way to be sure you are fixing the right clutch.

I'd try blowing down it and see where it goes. It might be blocked off. On a Suzuki there is normally a float chamber vent just around the corner from there on a flat you can see shaped like a figure eight. The vent is drilled into the top of that figure eight.. If there's no other vent then that's probably what it's for. Blowing will tell you..

Ha, that's crazy cheap. At that price you could keep one in your tool kit..

The book I looked in says the 4wd has a screw, but the 2wd doesn't show anything.. Presumably a plastic lug or clip ?

My internet's too sh** to see the video today Parham, but good work getting it going.. I'll try looking later. I don't know what technique you use with the pull start, but the suzuki owners manual suggests an unusual way of using the decompression lever when using it. Most things you just lift the decomp and then pull the starter. Suzuki say to lift the decomp and then pull the starter very slowly till the decomp lever just flips itself back to the closed valve position, then let the rope right back in, gently engage the pull start and then give it a hard pull. It's a good system. It means you've parked the engine with the exhaust valve just closed and all ready to start an intake stroke, and still leave the motor enough turns to get up to speed before the next compression.. You get full charge of air and fuel, easy pull and a reliable start.. Ha.. and now my internet goes and I see you follow suzuki's way already.. I only read about it a while back after years of struggling to get bikes to pull start..

"Wide open throttle". Gwb... This is a good forum Rgeiser.. friendly, helpful, and not full of pedants arguing about hypothetical ideals..

Don't know that one Mga.. Some have several wires.. But if you are sure those are the only wires then presumably a switch would do it.

I'd doubt the hose goes to the instrument panel.. They have an engine and airbox venting hose that runs up under the range/rev/4wd panel where it branches and runs back down as two open breather hoses.. You might be blowing into one of them. I'd try and aim it downwards so it doesn't accumulate water or dirt. I'd also change that fuel hose going onto the carb.. It looks like it's old or the wrong size and wall thickness.

They can get vacuum leaks where the carby fit on.. And you should check the egr valve is closing..

Has it got good compression ? Have you checked for vacuum leaks ?

Yup check the pressure with a gauge..

I think the parts places are pretty dependable, if they say your part will fit another model then it will, and the other model part will fit yours. It's easy to cross check. Look up your part and see what else it fits, then look up some of those models and see if their part is said to fit your bike, then if you really want to check their info, go to another parts site and repeat the whole process. You may find that your part is available under another part number. Sometimes under several numbers. Also, I'd consider pulling that bent arm and straightening it. The suspension and the wheel alignments on these things really aren't too critical They can be a bit misaligned and still track fine and have no problems.

I don't know what those symbols on the carb mean.. Off will be horizontal though.. I don't recognise that carb from the hose layout, it's not the standard carb we get here, but I think that hose at the top center in the last photo would be a vacuum, either for the pump or the tap, and there is probably another vacuum port for the other, possibly that plugged one. It's usual to have a bigger hose going to the pump, and a smaller hose going to the tap. The two vacuum ports have fittings to suit. In the first photo there's a hose opening upwards, that doesn't look right.. if it's a breather it should be aiming down to keep crap out. And the fuel hose in that photo looks about ready to split where it goes on the carby.. If that was a standard suzuki carb that up facing hose would be a vacuum hose I think. On the carbs around here, the left side of the carb has from front to back, a small vacuum hose fitting(pressed steel pipe) aiming up, then a larger vacuum hose fitting(machined brass) also aiming up, then the fuel at the rear(machined brass) also aiming up, and on the right rear there is a breather hose fitting facing down. I'll have a look later and see if I have an old carb like that to check what the ports are..

Nice Ulf. Nice clear picture, and the view from the top would be worth a walk let alone a ride..

You need to have a look at your fuel tap and see if it has a vacuum hose on the back of it. If it has a vacuum hose then that tap has no off position. In normal use you leave it on run or reserve and when the motor stops the lack of vacuum closes off the tap, when it fires up the vacuum opens the tap. The middle position of the tap is called prime and it's on all the time, it's for filling the carb if it's empty and there is no vacuum. If you don't know it's a vacuum operated tap and turn it to the middle position when you get off you are bound to get a flooded motor. If the tap is playing up it can fail to close when the motor's stopped. It only needs a speck of rust under the vacuum operated needle and seat in the tap to make it stay open, then you've got three on positions and no off. They can also get a hole in the diaphragm that operates the tap. If the diaphragm has a hole fuel goes down the vacuum hose into the motor. Lots of float needles leak a tiny amount, not enough to effect the running but enough to fill the sump with fuel when they sit for a while. The tap is the first and most important thing to get right. The manual taps can also develop leaks. There's a rubber washer in the manual tap with holes in it. On some models it's possible to flip the washer over so you are using the new unworn side. I'd make sure the tap was turning off completely before buying a new float needle.. It's easier just to pull the hose off and check there are no drips..