[ctandc]

maybe the jets are new, but what about the float needles, are they stuck

Well the floats were moving freely, not sticking, and were in spec.

The same exact carbs (only difference is the jet kit) ran fine on the SAME engine in the other bike before I tore it down.

This evening, I verify that the coils / ignition / plugs are good, then after that I'm pulling the carbs, putting the stock jets and needles back in, as well removing the 5 degree advancer.

[ctandc]

I'm at work and trying to get my head around this issue.

2001 750 engine ran FINE before I pulled it out. In fact I was a bit surprised how good it ran considering the air filter was nasty and the airbox had never been cleaned / drained. Engine had 4K miles on it.

1991 600 engine ran FINE when I pulled it out. Right before the swap, I kept tripping the main breaker, and it during the swap I found a couple of rubbed through wires in the main harness near the engine. I sealed those up with liquied electrical tape, then taped over each wire.

Swapped engine in. Got it fired up. Ran it around a bit and discovered it would almost bog and die when letting off the clutch...had to rev the crap out of it to keep it from stalling. It ran "okay" but seemed way down on power, even compared to my 600. After parking it, with it at idle, noticed that the #4 and #3 header pipes were so cool I could literally GRAB them where as the others were HOT. Also noticed massive oil leak.

Pulled valve cover - fixed oil leak (spark plug tower gasket).

Put bike back together fired it up, no leak, but still #4 and #3 act as if they are not firing much if at all.

Pulled plugs, #1 and #2 had oil on them (that's the side where the oil leak was) cleaned them off for later use, but installed BRAND NEW NGK's in all 4 cylinders at this time.

#3 and #4 plugs looked perfect...but did reek a bit of gas. Cleaned them off with compressed air and let them dry out.

Fired bike up (this is when I took the video's posted earlier in this thread)

It fired right up (had to choke it AND open the throttle)...it did backfire on starting. Ran rock solid smooth at idle with a bit of choke...let it run a minute or two, took it off of choke and it idled great. But just didn't sound "right". (highly technical term right)...and that's why I posted the video's I took to make sure I wasn't going crazy.

So I checked #4 and #3 exhaust pipes and they were cool...cool enough I could grab 'em and hold 'em.

At that point I checked to make sure I had fuel in #4 and #3 carbs...opened the drains and they had gas in the bowls.

Pulled #4 and #3 plugs (they look almost like they have never fired - I'll take pics tonight) and made sure the plug wires were making a good connection by cutting a bit off the wire and re-threading it on the boot.

Fired it up last night and the same thing...fired right up, #4 and #3 pipes cool enough to HOLD while #1 and #2 were HOT.

I have also tried swapping from the 93 750 CDI I bought for this swap TO the KNOWN GOOD 91 600 CDI that was on my bike originally with no change.

Now common sense tells me the coils aren't the problem, since the LH coil fires #1 and #4 and the RH coil fires #2 and #3. So each coil is dropping one cylinder?

I verified coil connections. Orange with White is the common positive to both coils. Verified that pos / neg terminals to coils were wired up correctly.

Verified I have 12+ volts at both pos coil wires with the key on and engine shut off.

Tested the RH coil I have been using and it's within spec on Primary and Secondary sides.

According to the service manual / wiring diagram / common sense, the next ELECTRICAL suspect is the signal generator.

[steves]

Didn't get to mess with tonight. I'm going to install both of the old coils that were running the 91 600 just fine when I pulled it.

If that doesn't fix it, I'm going to pull the carbs and go through 'em again.

Well I may try it but I don't think it's the coils. I've read several threads that talked of the newer 98+ coils being designed to drive a different type of spark plug that those of pre 98....until I cross referenced the part #'s and the CURRENT pt#'s for replacement coils for my 91 Kat 600 and the 01 Kat 750 (donor bike that engine came from) are IDENTICAL. So there goes that theory.

So I'm going to stay with the 750 coils (which ran FINE in the donor bike before I removed the engine). I'm going to cut the ends off every spark plug wire and make sure they are making a solid connection. Pull the plugs and clean 'em off. Make sure coil connections and CDI connections are good.

If I'm still dropping a cylinder at that point, I'm at a loss to be honest.

I'm getting gas to all the carb float bowls. The engine runs super smooth, even it does seem to be only running on 2 or 3 cylinders.

I wonder if I should try swapping the signal generator from the 91 600 onto the 750? The plugs were IDENTICAL and plugged right into my 91 Kat 600 harness...but now I'm grasping at straws.

UPDATE:

Just checked the 01 750 coils (Which have been on the bike since I swapped the engine) and both test within specs.

Tomorrow evening I'm going to check the signal generator as well.

Are the 98+ coils expecting TPS input?

[ctandc]

Are the 98+ coils expecting TPS input?

I was thinking along those same lines. That is until I went to Ronayers and checked the microfische...

The pt# for the 91 Kat 600 coil is now superceded by the identical part #'s of the L and R coils I have installed on the bike now, which came off the 01 Kat 750.

So that would mean if I had a bone stock pre 98 Katana 600 / 750 (no TPS) and ordered new replacement factory coils, I would receive the EXACT part #'s I have installed now.

So I would think the answer to your question would be no.

I wonder if the signal generator from the 01 750 is not compatible with the pre 98 CDI? It plugged directly into the harness thought and the plugs / wire configuration / color is IDENTICAL to the signal generator on my 91 600 engine...

[steves]

Maybe the problem is still related to how TPS might operate... if you are using the 750 coils, on the old 600 wiring harness that has no TPS connectors.... and on an engine that does have TPS connectors?

I don't know enough about how it works...

ANd I always use this rule of thumb: CDI, CARBS, ALTERNATOR, WIRING HARNESS all stay WITH BIKE, not engine.

[ctandc]

Maybe the problem is still related to how TPS might operate... if you are using the 750 coils, on the old 600 wiring harness that has no TPS connectors.... and on an engine that does have TPS connectors?

I don't know enough about how it works...

I need to verify that SOMEONE / ANYONE has used the post 98 carbs with the TPS unplugged on a pre 98 wiring harness with success. I've been told it works, but haven't confirmed someone doing it.

[David F C]

I'm lost. If it is not the signal generator I don't know what else could be. Can you get the engine to back to stock,test it, and then introduce a mod at a time. If that way you can't find the problem I don'k know how else you can find it.

Hmmmm, I'm puzzled...

[VifferJim]

PM SpecialK (if he's still around, haven't seen him in ages) or CP and see what they think...

Have you pulled the plugs out of #3 and #4 and know you're getting spark?? I thought I saw that you were somewhere along here... And, you know you're getting good fuel flow to the #3 and #4 carbs?? I'm almost positive I saw that in this thread.

If only it was something as simple as you having the wrong petcock on there - where you should have the two-outlet petcock and only have a one-outlet jobber running right now.

This is a good one.

[steves]

PM SpecialK (if he's still around, haven't seen him in ages) or CP and see what they think...

Have you pulled the plugs out of #3 and #4 and know you're getting spark?? I thought I saw that you were somewhere along here... And, you know you're getting good fuel flow to the #3 and #4 carbs?? I'm almost positive I saw that in this thread.

If only it was something as simple as you having the wrong petcock on there - where you should have the two-outlet petcock and only have a one-outlet jobber running right now.

This is a good one.

Keith still responds to emails... but doesn't have much time to get on the site.

[ctandc]

I may email him...

right now I'm going to hunt down a couple of hunches.

First off my battery voltage reads good. But it only takes a few times cranking the bike before it starts to drain... So I'm stopping by and grabbing a new battery on the way home tonight and let it trickle charge all night.

Next - I'm going back the 01 750 coils, verify all plug / boot connections are good - then tomorrow ( I'm off work) I'm going to run the bike a bit up and down the road to see if the #4 and #3 exhaust pipes heat up after running the bike at HIGHER RPM (into the main jet range) for a bit.


If it DOES, I think it might be something as simple as a clogged up pilot jet....even though the carbs looked CLEAN...it would explain the issue at idle.

We'll see.......

[hardlydangerous]

I would put my $$$ on it being the CDI
the CDI relys on input from the TPS for accurate spark timing.

If you unplug the TPS on a 98+ Kat it runs like a bag of **** and lacks power.

That's the only thing different that you are running from the complete 750 when you tested it. You can still run the 1 cable.

Find a 2001 750 CDI and hook the TPS back up.
If the fuel is ok, compression is ok then it's got to be your spark/ignition timing. And i'm betting the pre and 98+ CDI are NOT the same.

[VifferJim]

I would put my $$$ on it being the CDI
the CDI relys on input from the TPS for accurate spark timing.

If you unplug the TPS on a 98+ Kat it runs like a bag of **** and lacks power.

That's the only thing different that you are running from the complete 750 when you tested it. You can still run the 1 cable.

Find a 2001 750 CDI and hook the TPS back up.
If the fuel is ok, compression is ok then it's got to be your spark/ignition timing. And i'm betting the pre and 98+ CDI are NOT the same.

When you already looked everywhere except one place, chances are that's where you'll find what you're looking for...

[steves]

Okay, I'm thinking less about the TPS now... based on this diagram



Page 6-26 in the factory service manual. Could the advancer be in the wrong position?

Are the wires to the coil packs connected correctly?

[ctandc]

I would put my $$$ on it being the CDI
the CDI relys on input from the TPS for accurate spark timing.

If you unplug the TPS on a 98+ Kat it runs like a bag of **** and lacks power.

That's the only thing different that you are running from the complete 750 when you tested it. You can still run the 1 cable.

Find a 2001 750 CDI and hook the TPS back up.
If the fuel is ok, compression is ok then it's got to be your spark/ignition timing. And i'm betting the pre and 98+ CDI are NOT the same.

Remember this was swapped into a PRE 98 frame / wiring, which never had a TPS. And the 750 CDI I bought used came off a running bike...so it 'could' be bad, but the 600 CDI I've tried is the one that's been running happily on my 91 Kat since day one.

The TPS is meaningless to the pre 98 electronics. No input at all.

Okay, I'm thinking less about the TPS now... based on this diagram



Page 6-26 in the factory service manual. Could the advancer be in the wrong position?

Are the wires to the coil packs connected correctly?

The advancer only goes on one way. And I've verified coil connections. Orange w/ white is 12 volts coming from the CDI, and connects to each POS terminal on the coils. The two other wires are ground and go the negative side.

I'll know tomorrow morning if those cylinders are firing without a doubt, gonna hook up my timing light to the plug wire.

Just verified via inductive timing light that I AM getting FIRE to #4 and #3.

Tomorrow I'm going to run it around the block and get the RPM's up (off the pilot circuit) and see if those pipes get hot (#4 and #3) just now after running a couple of minutes at most, #1 and #2 were hot, #4 and #3 not.

I'm betting trash in the pilot circuit of those two carbs right now.

We'll see.

[steves]

Okay... that does point back to carbs then...