Mech

Drain or dip a bit of gearbox oil out.. look if it's got metal dust, chips or chunks in it.

Could there be a wire somewhere that's swinging around and shorting, or disconnecting when the bike's on an incline ? I've seen the similar symptom before, except when cornering.. several times actually. Loose battery...

If you scroll down there is a link to more information about them and it gives the amps volts ad watts. But even 1.5 amps is going to be flattening the battery at low revs I think... without a tail-light.

If you take the knobs off and then the plastic cover the cables are all under there, and the ends are all facing upwards after a fashion.. if you wanted to lube them that is where you would do it.. but I wouldn't encourage that. The cables have rubber boots and you would have to tear them to lube the cables, and if the bots are worn out already, then the cables are probably full of dust which won't go well with the oil. Best to flush the dust out with water or air if possible, then oil them.. if you must.. but I don't really think you should do that either. The cables have a nylon or teflon liner between the inner and outer, and they used to recommend they shouldn't be oiled.. Things might have changed but as far as I know modern cables should be flushed and dried(if possible/no boots) and if that doesn't fix them, replace them. Are you sure the cables are the problem ? Do they feel like they have a lot of drag ? The gears can be a bit hard if you don't either back up to change, or, change on the run by throttling on or off just as you slip it into the next range.. always at slow speed though. To check if the cables are stiff, and the problem, disconnect them all at their lower ends(not too hard), and then see if the levers move nicely.

Those spotlights actually draw 180 watts of electricity Dave.. That's 15 amp for both or seven and a half amps each.. Even one's already blown the power budget at full revs.. At moderate revs the battery will be going flat. If the charging puts out about thirty watts, which is what the manual says it does at 5000, then it will only be 2.5 amps at 5000 revs. At lower revs, say 2000, we might only get one amp, possibly less..

The charging only puts out about 30 watts at high revs, and a lot less if you\re driving around a bit carefully and at slower revs, as you should at night. I'd try rigging up a variable resistor or load of some sort, and use it to check what sort of current I could get out of it (at driving sort of revs, not high revs) before the volts dropped below about 12.6.

Well spotted..

It needs more petrol ? Pull the spark plug out, connect it to it's lead and rest it against the head so you can see the spark gap, then look for a spark as you spin it over. If you do it in a dark place you will see the spark easier.

Your battery may be causing the problem. Is the electric start operating ? You should check your charging system is operating correctly. Is it charging and regulating ? An easy test to see if the charging system is causing the problem is to turn the headlights on and see if it will rev a little higher before it plays up. If turning the headlight on makes a difference, then it's your battery or charging.

Standard times become pretty irrelevant once things are that old, and a quad bike. A single seized screw on the bodywork can hold things up. I was a mech and I always charged for all the time I spent productively working on the machine. If I get sidetracked in my diagnosis and spend time "barking up the wrong tree", then I discount that time. If I break some bolt off unreasonably, I fix it at my expense, if the break was unavoidable and necessary, they pay. Old machinery needs more time and care than new machinery.. People were always very happy to pay me and they always insisted that my terms were more than fair. The whole thing about being professional is in giving people every reason to have confidence and trust in you and your methods and workmanship. Explain the complications, and the problems, and what you've charged for...

The fuel pump may have a hole in it's diaphragm allowing fuel down the pump's vacuum hose.. You can check by sniffing or sucking very carefully on the pump's vacuum hose.. if it's got fuel in it then the diaphragm's holed. And I think the fuel tap you have doesn't have an "off" position. If it's got a "Pri" position, that stands for prime, and it's because both other positions, main and reserve, are both turned off automatically when the vacuum's not being applied to a diaphragm on the back of the tap. If there's no vacuum being applied then the Pri position allows fuel to flow, which is handy if the fuel has run out and the carby is empty. If your bike doesn't have a vacuum hose to the back of the fuel tap, then you have probably been running it on Pri, and the diaphragm operated positions have both been off positions for you. Perhaps the diaphragm in the fuel tap has got a hole in it now.

Suzuki quads have a bung at the back of the muffler and it's part of suzuki routine service to take the bung out and start the motor.. But you know, in forty years of servicing suzuki, I've never seen a blocked muffler, not unless it was a blown motor and the muffler was full of oil. On various bits of machinery though, and vehicles, I've seen blocked mufflers, and it causes spitting out the inlet and bogging down as the revs build. The usual way to diagnose it is to attach a vacuum gauge and rev the engine on the spot. If the mufflers blocked the vacuum drops steadily away as the revs rise.

Yeah that hose into the float bowl to check the float level has been used for half a century or more by mechanics.. I've been using it for more than a half century.. haha. It's a toss up whether it's best to check for fuel flow right through the carby first, or whether it's best to check it's getting to the carby as a first step. Either way we have to go on and continue looking for good flow or blockages if there is anything not right. I always suggest to people that they do the easy things first, (even if the easy thing seems unlikely, it's best to eliminate it before going for the complex stuff). Mostly, even on the side of the track, we can pull the fuel hose off and check for fuel. It's the "simple" that people need to have in their mind when they do find themselves broken down and wondering what to do. And... for Spr or anyone else reading this that is not used to diagnosis.. when we diagnose things there are two things we need to consider, the symptoms, and the circumstances.. If someone says their car makes a rumbling noise it means nearly nothing, it's just a symptom alone, but if they say it makes a rumbling noise when they go around corners, it tells a whole lot more, and if they say it's only doing it around left hand corners, then it's getting real clear what things we should be looking at. If a bike stops running at the track, that is an entirely different scenario to a bike that has sat for a week and now won't start, or a bike that sat in a shed for ten years and now won't start. So we need to know if it manifests the problem hot, cold, after a long sit, after a long or short ride, cornering, decelerating or braking, when it's wet, at part throttle or full throttle. . As far as symptoms go, we need to look for every symptom our senses can detect, visual symptoms, sound, smell, vibration or heat, even sometimes a taste we get in our mouth from certain things (no, don't go tasting things). Every symptom, and every circumstance can help diagnose a problem, and if we look really diligently for a symptom or a circumstance and it's not there, that allows us to ascertain the problem through a process of elimination.. The symptom or condition that's not manifesting can rule some things out. That's why we need the full history Spr.. Haha.

Yup, there are several things, or combinations of things that could cause it... So, Spr, in the thread title it says "popping" out the carby and then you describe it as "spitting fuel" out the carby. If it's just spitting fuel then it could be a blocked exhaust, not enough clearance on the inlet valve adjustment, worn cam bearings or a mistimed cam. If it's backfiring out the carby(with a flame/loud pop), then it could be all sorts of things either fuel, electrical or mechanical.. At the moment to me it sounds as if the mixture is too lean, which causes it too burn too slowly, and so have lingering pockets of flame when the inlet valve starts to open.. And those lingering pockets of flame, ignite the incoming mixture every so often giving that "pop"... And yes, all this happens even despite the exhaust stroke having supposedly swept the cylinder clean. Flame can "hide" up the spark-plug or in the corner between the valve and the head. The changed carby could cause all this. If installing and disconnecting the air-box makes a big difference, then it points to the carby operation, not electrical or mechanical. Since it's simpler and cheaper than fitting new parts, you really need to make sure the new carby is set up for your bike, and the local altitude, temperatures and fuel grade. The simplest way for you to do that, if the replacement carby is an identical design as the original, is to change all the jets and needle and discharge tube which the slide needle drops into. If the new carby isn't identical then you need to first clean and adjust the carby, then set it up with the air-box and filter, then diagnose speed range and which jets or adjustments need to be made. You tune the idle jets and mixture and speed, which in your case souds about right already, then you adjust the main jet so it has fuel right to full power, you figure this by reading the spark-lug after taking it for a short full throttle blast, then after that you adjust the needle slide. Get the carby right and I'll bet your problem will be fixed.. Oh, and Spr.. it would be a probably help if you told us the history, how long you've known the bike, what the original problem was, when and under what circumstances it arose, what you did first, how the work has unfolded..

Not familiar with it but it's probably more likely the seal than the gasket, but I'd check the bearing in there too to make sure it's not play in the shaft making the seal leak.

What Curtis is showing there is a good way to check the float height, but it doesn't guarantee that there is enough flow of fuel to keep the bowl full once you open the throttle.. You need to disconnect the fuel hose from the carby and lay it sideways into a bottle, then either turn the tap on or start the engine so the pump operates, and check the fuel is flowing out of the hose at the full diameter of the hose. It's a good idea to check there is a good flow of fuel when you open the throttle too if it has a vacuum operated fuel pump. Start the motor, hop on and lock the brakes, put it in gear and give it about half throttle so it's starting to load up a bit.. the fuel should still flow out of the fuel hose at full diameter, if it doesn't, you may have a weak vacuum or a crook pump.

It's probably best to download a workshop/service manual and have a read.

If it idles fine it won't be a valve problem. It sounds to me like it's not getting enough fuel. Either that or the exhaust is blocked. As has been said, aftermarket carbys are not set up for any particular market or altitude or fuel grade, they all need adjusting. I mostly take all the old jets out of the old carby and fit them to the new carby, slide needle and discharge jet included. Before you do that though, (because this is easiest, but you don't mention having done it), you should check there is plenty of fuel getting to the carby by disconnecting the hose from the carby and running the pump if it has one.

Look up a parts place online and look at parts that tend to vary from model to model, such as carbies, bodywork, electrical components, speedos.. It's pretty easy to identify which model you have. Also, some parts lists have a feature where you can look up a part number, and then click a link somewhere that shows you what other models that parts fits. This can be handy to see which other models do have that part your bike has, before going o to explore those other models and comparing their parts with what you have. If the first spares site you look up doesn't have that cross reference feature, it's worth looking for a spares site that does have it.

Ok, well the bearings should tap easily onto the cv shaft so something is wrong there. Not in the hub or way you've done it, something not right with the dimensions on one part.. Good work fixing the leak though. I'd try disconnecting the battery overnight or for a few days and check that the battery doesn't go flat by itself. Then I'd rig up an amp gauge and check for discharge when I reconnected the battery. It shouldn't have more than a few milliamps with the key off, two or five milliamps are probably ok, any more and there is a fault. Some voltage regulators are connected direct to the battery and don't get disconnected when the key gets turned off, the wiring diagram will show it. If the current draw is too much disconnect the reg and see if the discharge disappears.

Oh.. I thought the cv shaft poked through the bearings til it butted up against the seal's shoulder on the shaft, (that should be a palm fit), then the wheel's hub with disc, slides on splines, onto the outer end of the cv shaft, till the wheel hub butted up against the bearing. When the big nut gets done up it clamps the bearings between the cv's shoulder and the wheel hub. Without the nut being done up, and if everything is nice and clean and lubed, you should be able to knock it apart with the wooden end of your hammer handle. If you are having trouble getting the wheel's hub onto the cv's spiines, where they are meant to slide on the splines, it might be the wrong number of splines on the shaft, or the bottom of the splines might be dirty on the wheel hub. A small triangular file is good to clean them. The splines should slide together with a palm or light tap..

It does sound like the sort of thing that could come right with a little adjustment to the idle settings. An air leak around he manifold could cause it too though. I'd try adjusting the idle mixture and speed when it's warm first off..

Hi. Perseverance always wins.. Clean the shaft and it's splines, clean(using a small triangular file if necessary) the wheel hub's internal splines. grease it all, and then work the cv shaft through till it's all the way through the bearings and seal. I've done it in place by holding the whole hub in my hands and bumped it against the inner cv and diff, via the shaft, till it hammered gently through, but you need to be gentle doing that, or, if I've had the boot off the outer, or taken it off for the purpose, I've tapped on the inner end of the outer cv. You need to part rotate the shaft every few bumps/taps to ensure it's not trying to go in crookedly. It should go through easily, every bump or tap should sound and look/feel as though it has moved. If it's not progressing easily tap it back out again and check what's tight.. Once that's in right you should be able to refit the steering knuckle to the swing arms, and holding the cv from behind, gently tap the wheel flange on far enough to get the big nut on the center and pull it up tight. While tapping, or tightening the big nut to get the wheel flange on, make sure to rotate the whole thing every few taps or half turns of the nut. All the bits, other than the bearings in the steering knuckle, should slide together firmly, about what we call a "thumb", or perhaps a "palm", fit. A thumb fit means you can press things in with a thumb, and a palm fit is a bit tighter and requires a palm to press the part in. Given that it's a bit inaccessible from behind, a tap or bump is ok to get the shaft through, and to get the wheel hub on. Once it's all together it's a good idea to tighten and then loosen the big nut, turn the wheel several times and then retighten the big nut.. Better still turn the wheel hub while you are tightening the big nut.. It should when tightened up, turn with a little resistance but not be tight, or noisy, or feel rough/rumbly.

If the bung has a flange, try tapping that around with a small slightly blunt cold chisel, or a nice new engineers punch with a sharp (90 degree) edge to it's end. If there's no flange then try tapping on the flats, near the ridge the socket usually touches. If you use a chisel there, you can sometimes raise a little metal on a couple of flats and it's enough, with the nudge from tapping, to allow the six sided socket to grip. Tapping the plug on it's end might also loosen it a little, and at the same time splay the edges of the hex, allowing a little more grip for the socket. Don't hit too hard anywhere, or use too sharper chisel.. The idea is to raise a little metal as much as move the plug.

Do you mean the plug's real tight in there, and the head of it's rounded off so you can't get it out ? Have you tried a six sided socket ? If that doesn't work they I'd use a small blunt cold chisel or engineers punch to tap the head of the drain bung around a tiny bit, a little on the left, then a little on the right, then a little on the left again, then try the six sided socket again. Put the socket on then give it a tap with a hammer to make sure it's right on and to loosen the grip of the drain bung. Then you need to apply as much pressure as the grip of the socket will allow, and hold it there till the plug begins to move. It you mean the drain plug is out but the threads are stripped in the case where it goes, you could ask at an auto shop and them will be able to get you a slightly oversized plug.