Mech

CJ.. have a look at the manuals, they come in a lot of different versions, some do only one year, some do many, some of the manuals here are correct for the american market, but not right for other market's years. Trying to classify them all without doubling them up in a lot of folders would be impossible..

Yup.. good to get the kids or grandkids involved. Teach them skills and self reliance.. and how to keep out of the clutches of thieving mechancs !!

There's little or no satisfaction in doing what's easy. There's always satisfaction after overcoming difficulties.

People fit aftermarket carbs when all that's needed is a careful clean and adjust a lot of the time, or to see if it makes a difference to their badly running bike.. It's better to clean and adjust the original carb in most cases. The only bit that wears is the slide and the body where it runs. If that bit's badly worn and causing a problem(hardly ever), then buy an aftermarket of the same make and model, then change all the old brass jets except the float needle and seat into the new carb body.

So if you put it straight into second gear. would it go faster or start struggling even earlier ?

If it's a carb problem then it should rev up when you open the throttle and squirt some engine start down there..

The higher resistance primary reading means it has more, finer, windings, and so draws less current Params. That's ok as long as the secondary windings are in a suitable ratio to the primary; so the step up in voltage is enough to throw the spark. If it was a multi cylinder and had to throw more sparks per second then it's an advantage to have thicker wires so they carry a heavier current and so magnetically saturate the iron core faster. In this case, of a slow revving single cylinder, there is plenty of time for the magnetic field to build, and so a low current through a lot of fine windings will do the job adequately and without using too much power. The conventional coil in a 12v system builds up a magnetic field in the core relatively slowly while the power is flowing, then cuts the power and the rapidly collapsing field cutting through the secondary windings induces a high voltage. In the cdi system the capacitor gets charged up to hundreds of volts and is then discharged through the primary windings, and the rapidly expanding magnetic field cutting across the secondary windings induces the high voltage. One system induces the spark on the expanding magnetic field, and the other uses the collapsing magnetic field. The coils are different. The resistor cap is not very critical and isn't dictated by the primary resistance. The overall resistance of the lead, cap and plug is normally about 25Kohms.

I reckon if it was revved up with a strobe timing light attached, the spark would stop happening as the rev limit is reached. That's what it sounds like to me listening to the downloaded video..

Have you tested the battery yet ?

It sounds to me like an electrical problem. In the video it sounds like something's switching the ignition on and off really quickly when you rev it up.. That doesn't sound like carby to me.. Does it run any better if you turn the headlights on ?

Use jumper leads and connect a battery...

Big paper gaskets often shrink or expand. If they are too big when you go to fit them you dry them out in the sun or in front of a heater. If they are too small when you go to fit them you steam them a little over a kettle.

http://www.motormasterpowersports.com/UserFiles/File/Jan18_MMPS_U-joint.pdf

No, I don't think it has a centrifugal advance. They might fire the ignition at a low point on the rising side of the pulse coil's AC wave, in which case there is a natural advance as the voltage rises to the trigger point earlier with a faster moving magnet,(that's how most older cdi systems worked) or.. They use the change from rising to falling of the pulse coils AC wave to trigger it,(which is consistent and accurate no matter what the voltage or air gap), and then do a sort of calculation for advance inside the cdi unit, which is how most of them have been for a long time now. Some motorcross bikes and road bikes have switches on the handlebars now to choose how much power you want. The kawasaki with it's 12 volt system being triggered by the pulse coil, will be one of those two systems for timing, the only difference being most bikes now have cdi which use a low impedence high voltage coil, and the kawasaki is using a higher impedence low voltage coil.

Not sure about the toyota.. The nearest thing to these is an old points and capacitor ignition.. Except they've replaced the points with a transistor. They did use then in cars, mostly with an optical sensor/trigger. This uses a pulse coil to trigger the firing.

I'd seen that broken bolt earlier.. Good work. I always use a tiny chisel (made of an old pin punch), to get broken bolts out too.. Whenever possible.

The key you can buy from yamaha or an engineering supply shop. The brass bush I'm not sure about but if you could post a picture of it we might be able to suggest something.

It sounds like a dead battery. If the battery was good and charged up, I'd expect it to run the bike for hours if there weren't too many electric starts or headlights. You need to charge the battery with it disconnected from the bike, then turn the charger off and let it sit for an hour or four and then use a gauge to check it's voltage. It's voltage must be 12.6 or more. That checks the battery isn't self discharging. Then put it in the bike and before connecting the earth lead use the amps gauge to check for any discharge while the key's off. There shouldn't be more than about 2 milliamps. That checks the bike isn't draining the battery. Then you connect the negative lead and start the engine and use the volt gauge on the battery to check the voltage is going up. It should go up to about 13.7 volts quite quickly and at an idle, and with a few revs and a few minutes it should get up to 14.7 volts. After a few minutes of running it should be somewhere between 13.7 and 14.7, and if you turn the headlights on it shouldn't drop below 13.7 as long as there are a few revs on. That all checks it's charging. The last check is to turn the headlights off and hold the revs up watching the rising voltage and it mustn't go above 14.7 volts. That checks the regulator's working.

Yeah I'd try to straighten it rather than cut it.

I suspect that old 12 volt coils are getting rare, in these quad bike designs anyway, and so every one is getting sold coils made for cdi, or some multi purpose coil that can/might operate on cdi or 12 volt.. A 4 ohm coil draws 3 amps, a 2 ohm coil draws 6 amps, a 1.2 ohm coil draws 10 amps..

The different resistances are probably because some are using old silicon transistors and big capacitors and circuits that draw power, and others will be using metallic oxide semiconductors. Transistors are current operated, and metalic-oxide semiconductors are voltage operated. MOS just need to sense a voltage on their triggers to start conducting, they don't require any current at all compared to a transistor, which conducts in proportion to the amount of current being fed into it's trigger..

No the pulse coil just triggers the ignition to fire. It doesn't effect the current through the coil other than turning it on and off. It does set the timing.. If it wasn't working you'd get no spark at all. There's a chance the ignition unit might be damaged, and not putting power through the coil for long enough, or with enough current, or not cutting it off cleanly as it should at the instant it fires the spark, but it doesn't seem likely if you get some spark out of these low resistance, poor spark, coils. If you can't get a good spark on the bench with 12 volts, don't expect the bike to perform some miracle and make then throw big strong sparks.. It's not a cdi and it's not going to do it.

I'm not sure a gasket is a good idea Gw.. Water gets down the pull handle anyway..I think some even have a small dimple bent into the metal to leave a drain hole..

One tree might do it. Chain it to a tree, put blocks under the chassis in the right places, then a big lever might be able to twist the frame, or bend tubes. Or yeah a second tree with a block and tackle.

Sounds right.. I think it only happens as the engine bounces backwards as it stops. So I wonder whether there is meant to be some different rocker that hangs over the edge of the cam face enough to get held up by that flat.