Project FZR fix up

https://www.megazip.net/zapchasti-d...50-8618/fzr250-19068/3ln1-768321/n-a-13355947

 

This is what I would do.

Read the voltage across each coil (the small spade terminals) with a fully charged battery and ignition on. You should see a constant 12 volts. Assuming that is OK, read again when cranking the motor. They should ground out and come back up to 12 volts again. You may or may not be able to see it depending on how good your meter is. If you get good readings then your TCI and pickup should be working fine.

Then I would check the spark on all 4 plugs, leads, and caps, if anything looks suspect then rip it out and replace it.

Regarding the twin coils and leads. There are only two possible combinations, since each coil fires two cylinders at a time (with one being a wasted spark at top dead centre of the exhaust stroke - hence the name). The length of the leads will give you a clue, unless they have previously been chopped or replaced.

Fizzers are really sensitive to fuel supply to get started in my experience, especially if the pilot system is lean (partially blocked jets or too lean on the screws). If the float valves are leaking and the fuel tap is on, they will fill the intakes and your cylinders with fuel. To put this in perspective, the volume of the cylinder is compressed to roughly 6.5cc's, so there is zero chance it will fire. The fuel with be forced past the rings or valves, out the exhaust etc.

They don't like old stale fuel either, they tend to pump it out the exhaust where it ignites thanks to the wasted spark, letting out massive afterfires.

Speaking of which, you said you got to backfire. Is it actually backfiring out the inlet/carb, or did you mean after-firing out the exhaust?

 

Alright, you need to sort out this issue with the coil(s) before anything else.

If you are not getting 12v across the coil, there are only a few things that can cause it.

A dead coil (open circuit or shorted out) - most likely
Broken wire or high resistance in the wires from the TCI to the coil - second most likely
Faulty TCI - unlikely unless the voltage regulator has failed and killed it - happened to me with a Zeal. I also blew a coil wide open because some idiot put a 30 amp fuse in the ignition circuit which has a 5 amp fuse as standard, and there was dodgy hack job wiring to start it without an ignition barrel.

If you have a wrecker or are looking on ebay/gumtree etc, the Zeal uses the same coils, just with a different part number prefix (3YX instead of 3LN). You can use a Zeal TCI in a pinch as well, just to rule yours out.

After you have the coils sorted, drain the fuel tank and carby bowls and get some fresh stuff in there. Fizzers really do not like old fuel. How long as it been since it was running on all 4?

And did you end up doing the valve clearances?

Keep persisting and you will get there...