Mech

Yeah that's right. Some of the figures are ohms, some are Kilo-ohms, and some and Mega-ohms. You have to have the test leads the right way around. At the top left of the chart it shows + / -. If your coil has a low ohms reading though(which it has) then it will be drawing a bigger than standard current and will be straining the current flow. I think you need to check what sort of spark the coil has if you use a 12 volt battery and two jumper leads to fire it off. Then you will know whether the coil is capable of making a decent spark or not.

Yeah but if I log in as a guest I don't get advertising.. I use mozilla firefox.. for linux, or Win ten with er.. some gimmicky thing.. Edge I think it's called. As a casual visitor I don't get much advertising.. I have all my security settings set to not interact with the world automatically as much as possible. I'm an internet hermit..

Oh yeah, the son would like that. It'd go right next to his coventry-victor. (Also horizontaly opposed).

Seems it's made by a company generally known as Highper.. Which may or may not also be Hyper.. But either way there's not much info on them, not even a parts supply to look at pictures, which would perhaps help identify a de-comp. Perhaps if you show us some pictures of the top of the engine.. If there's a vacuum de-comp it would be obvious I think.

You need a good 12 volt supply to the ignition coil. Without any voltage drop from the battery to the coil when it's under load. The load should be about four amps.. A car headlight bulb would be enough load to test the 12 power supply to the coil. The ignition unit shorts the coil's negative terminal to earth for a few milliseconds before it wants a spark, then disconnects the coil from earth at the instant it want's a spark. The ignition unit also controls the ignition timing, and in that bike it has a wire coming from the gear change indicator unit to the ignition unit which they say to check for no spark situations. (I see you do get a spark now if the spark plug lead's cap is off.. That's good. ). The ignition unit has to have a good earth so it can earth the coil properly. The unit's earth needs checking for voltage drop under load. A car headlight in the place of the coil will be a good load. Since you do in fact have a spark though, I'd suggest you leave the spark plugs cap off and use a split pin or a bit of bent wire poked down the end of the HT lead and connected to the spark plug, to check for spark and try to start it. It's possible you are using a resistor plug and a resistor cap, and possibly a resistor lead on the coil.. Each of which makes the spark just a little thinner..

How long have you been running it without a battery ? That might be the trouble. And Gw's right about after-market carbs.. they always need stripping and checking before use, then some tuning quite often. Unless the old carb is badly worn in the slide I'd reuse that. The way you are describing it I'd suspect that if it is a carby issue, it will be something wrong with the main emulsion tube, that's the brass tube going from the main jet up to the slide needle. The tube has tiny holes in the side that need cleaning, and the drilling it fits into needs to be clean, and the air jet near the air-cleaner end of the carb needs to be clean. Oh.. the breather hoses need to be clean..

I couldn't see the link Params. The coil will only make one spark every time you disconnect the power from it's two primary terminals. The spark will be from the HT lead to the negative coil terminal. If you connect the sparkplug and the jumper to the coils negative terminal, and then just rub the positive jumper clamp on the primary positive terminal it should make and break contact as it scrapes along and make several sparks.

Hmmm.. Haven't been able to upload that. Here're the bits you need though..MXU300.pdf MXU300.pdf

Ok, just found a manual for a MXU300, and it's ignition coil is meant to have a primary resistance of three point four to four point one ohms resistance. I'm uploading the manual at the moment, it won't be available till a mod has checked it though..

Yes I believe your MXU is a 12 volt ignition.. Some of the kawasaki use a 12 volt system. The specs you quoted for resistance, were too high for a cdi system, so the bike you were quoting for (the 200 kawasaki), is a 12 volt system. Then, the measurement from your coil is too high resistance to be a cdi coil unless it's shorted out, so it seems your bike is 12 volt ignition, like a kawasaki. Your resistance reading though is a little low which could mean it's partly shorted inside. That would make it draw a higher current than intended, and it would have a weak spark. Try using a set of jumpers and try the coil on 12 v.. it should throw a good spark with it's cap off the lead.

I'm not sure Notall. Most have some moving parts.. A pin that comes out or a ring that turns.. If they are mechanical. I think you'd have to pull the cam cover off to look. Your one might be operated by vacuum and that might be why putting your hand on it works so well. If i't s a diaphragm one there should be a fairly large diaphragm somewhere obvious.. I think. Have you tried the jumpers off a good battery straight to the engine and the starter motor ? To eliminate the starter solenoid. Do you know the make ? We might find some manual for another model that's made by them, that has a de-compressor.. It might tell us something.

Cdi ignition coils have very low primary resistance, from about point one of an ohm up to about point four of an ohm. Twelve volt ignition coil primary resistance is higher, from about one ohm to three ohms. Are you sure the earth between the coil mount, and the engine are good..

There are heaps of variations. You will be able to download several manuals and they will have several different wiring diagrams each. You need to count and take note of the wire colours in the cdi unit, and the key switch, and that will narrow the possibilities down when you start looking at the manuals.

Oh, and another thing.. Most coils need to have the primary terminal they share with the secondary windings, going to the earth. If they are back to front the HT has to earth back to the shared primary terminal, and then back through the primary windings on it's way to earth. The right way round the primary current goes through it's coil and to the common primary terminal, and when the HT earths back it just goes through it's windings to the common primary earth terminal. There will be a best way around for the coil....

That coil resistance is too much to be for a cdi. The most I've ever seen for a cdi is, I think.. Er.. point seven of an ohm, as the maximum allowable. It would appear it is for a 12 volt system, but, it is a little lower than specs which would suggest an internal short.. which would give a weak spark.. The thing a lower than intended resistance would do, is it would draw more current, and strain any bad connections. I think you need to test the coil, then check the wiring. I think I'd test the coils spark with a known good 12 volt supply.. from the ends of my jumper cables.. If you just tap or wipe the jumper over a terminal so it makes an interrupted connection, it should make a lot of good spark.. five mills easy. If it does make a good spark with twelve volts, then it's back to checking for the bad power or bad earth I think.. Because the ignition unit only turns the coil on for a fraction of a second before switching it off to produce the spark, it's going to be hard to find it by a voltage drop.. not with a digital gauge anyway. I think you just have to check things by eye and feel..

And both of you guys, Param and Mule, both need to check your ignition coils are the right sort for 12 volt ignition systems.. The most common sort of coil now is for cdi, and you can pick them up for a few bucks. 12 volt coils are getting rare. Cdi coils are made to run on hundreds of volts. If someone fitted a cdi coil it's not going to make much spark from only 12 volts. cdi coils have very low primary resistance, about point one or point two ohms. 12 volt coils have a primary resistance of about two ohms.

Do you have a battery in it ? Have you checked the charging is charging, and regulating ? To reply in here you go down to the bottom of the thread and type in a box, then click on the "submit reply" button to post it.

It may be that the ignition system is like some kawasaki and not a cdi system. Since it made your test light flash when you used it in place of the coil, I'd suspect you need a 12 volt ignition coil, not a cdi 300 volt coil..

If the spark plug cap comes off the lead try taking that off and checking the spark. The cap might have too much resistance or a short. Also have a look at night and you might see sparks running along a rubber boot or across the coil to earth.. If you have a timing light, connect it up but put a screwdriver through the pickup, then use the screwdriver as a probe looking for leaking voltage.. It'll make the timing light flash if there's an HT leak..

They are quite soft, and can bend.. As long as we are gentle we should be able to bend them straight again.. Heat would help but then it's hard to handle and work. I think I might heat it and let it cool as slowly as possible, cover it with hot ashes would be good.. That would soften the metal to it's softest natural condition, called normalizing. Then I'd use a one pound hammer on an anvil. The trick is telling when it's right again.. Have you figured that out ? Might have to take the other side out and use that to compare as a mirror image..

The diagrams show several different switches, with different behavior. Some are just a single set of contacts, and some have two sets of contacts, and the two contact sorts can work both poles in parallel, or inversely, (so when one goes on the other goes off).

Yes I've seen eight dollar bearings when the good ones were twenty.. they were hardly fit of the wheel barrow !

I'd be a bit cautious about bearings that are too cheap Kp. Make sure they are an old and recognised brand, and of the correct clearance. Also some japanese seals are special, with some sort of hard wearing lip to them. I always get the old seals out and check them before going off and buying a seal from the local engineering supply place. Some I get from the dealer..

The cdi units come in a lot of variations Quadman, you really need to identify your one absolutely. If you check how many wires the cdi has going to it that narrows it down. You need to look at the wiring, not the cdi. Count the wires going to the cdi, and tell us the colours and we can try to identify what wiring your bike has, then check you have the correct cdi for that bike. Modern cdi units have the tune for the bike designed into them. If you buy an after market one it is likely to run, but not be tuned correctly, which can badly effect the engine. If you have to buy a new cdi, I'd recommend a genuine yamaha one..

The starter shouldn't operate with the kill switch or the main switch turned off.. but it does.. or was. That sounds like the wrong key switch to me..