Ignition pickups and cdi testing

[GaryS-NJ]

I'm troubleshooting my 1995 katana 750 that does not fire on cylinder 3. I went through carbs, verified coil voltage, and saw spark under compression in cylinder 3 but just realized that could be #2 waste spark.. And I swapped coils and still #3 doesn't fire. I'm working and can't research schematic now but can anyone say how many ignition pickups there are and or post a link to help isolate between CDI or pick up (or wiring).. Physical location of connectors would help too..

[92xjunker]

1 picked up coil, 2 pulse triggers. It's a fuel issue......if you're plug is dry it's not getting any. Just a thought.....have you checked the valve clearances yet? It is possible...... still think it's fuel...

[GaryS-NJ]

Thanks again. So if it fires on 2, it has to fire on 90 degreeslater on 3?? The pulse triggers you speak of are sink transistors or fets which is common for 2/3? So then it would have to be the get controller missing one cylinder which is unlikely. I troubleshot a CDI for my old Yamaha and it had 4 sink transistors. Yes, the plug looks dry and I even started it with the plug out to look for mist.. Didn't check lash but I have compression so I would think it would fire somewhere on the rpm scale or at least pop out the pipe or intake. I just don't see how the bowl could fill (I even checked the bowl fuel height!) and pilot jet clear and paj1 clear through the 3 orifices and the emulsion tube and needle opening (gonna see that with air cleaner off next), and not get frigging fuel into the cylinder. Thanks again for your continued tech support

[92xjunker]

It's the pilot circuit.. The passage under the pilot jet. Some run fishing line threw it.

[92xjunker]

As far as trigger timing, it is a wasted spark system. (both plugs fire at the same time), only the plug under compression will actually ignite. it is a magnetic pickup type trigger (found on the right side of the engine, under the small cover). Duration and advance are controlled by the CDI on an RPM curve. The manual covers it and how to test the ignition circuit.

[GaryS-NJ]

Silly question, but I'm going to have the carbs off AGAIN later and can you say where to where the fishing line should go?? Last test with the coils swapped I tried sending propane directly into the #3 throat and didn't make a difference but revi,g it I could see fuel sucking past the needle.. And this time #2 and #3 weren't firing at idle but the do fire if I rev it as evidenced when I pulled the signal off that coil it was very dull revving (with the coil wire it revs nice). And this time she needed choke to idle). Really sounds like fuel now. And I sprayed carb cleaner and wd40 on throttle shaft washers and intake boots without noticing any air leaks..

[ZookRick]

how do you know it has enough compression? Did you do a compression test?

[GaryS-NJ]

Yes. Did al compression test. All around 140.

But with 92xjunker help, I'm sure I nailed it now! The small carb body orifice from the pilot jet to the main jet was clogged. Kicking,myself now because previously I wondered how the pilot got fuel but I didn't see the orifice and just kept going.

Side note, I butchered one of the pilot air jets on removal and my paj's are 1.3. I have/had California emissions and have the 5ez63 needle with 32.5 pilots. The carbs are not marked but assuming they are e-33 carbs, the manual says I should have 1.25mm paj's. I have to buy one anyway so should I just buy a 1.3 or get four 1.25's ??

Second side note, I removed the fan too. What the he'll was that for? Seemed to just blow a little air on the #1 carb bowl...

[Kreylyn]

Yes. Did al compression test. All around 140.

But with 92xjunker help, I'm sure I nailed it now! The small carb body orifice from the pilot jet to the main jet was clogged. Kicking,myself now because previously I wondered how the pilot got fuel but I didn't see the orifice and just kept going.

Side note, I butchered one of the pilot air jets on removal and my paj's are 1.3. I have/had California emissions and have the 5ez63 needle with 32.5 pilots. The carbs are not marked but assuming they are e-33 carbs, the manual says I should have 1.25mm paj's. I have to buy one anyway so should I just buy a 1.3 or get four 1.25's ??

Second side note, I removed the fan too. What the he'll was that for? Seemed to just blow a little air on the #1 carb bowl...

The Pilot air jets need to match, so verify what you have and order accordingly.

The fan was designed to cool the carbs to reduce the amount of fuel fumes that would be evaporated from engine heat. All it really does is run down your battery.

Krey

[GaryS-NJ]

Still not running right

Well I thought I had it licked after cleaning those carb body orifices that feed the pilot jets off the main jet tube. I got a replacement mikuni PAJ 30 to match the others and on reassembly, #3 was firing but 1 &2 dead and I isolated to a stuck float on #2. Fixed that and then #2 was dead. So I moved that new PAJ from 2 to 1 (didn't make sense but just in case) and then 1 was dead. Recleaned #1 pilot circuit and moved that air jet to #3 and. Then 2 was dead again (I didn't touch that frigging carb). Then just running and #2 came on and 3 went cold. At this point, it really seems like an ignition issue with one cylinder always dead. I'm going to start a new thread on troubleshooting that.. (Oh and yes, I checked resistance on the coils and redid the connections at the coil that was feeding #2/3..).