The wrong kind of Kaw triple

Simply cannot get #2 cylinder to fire. I've played whack-a-mole as far as fixing cylinders firing and not firing, but here's the rundown on what's been done.

-Replaced all float valves, cleaned all carbs, replaced all gaskets.
-Top end rebuild, adjusted valves, replaced shims accordingly.
-Replaced #2 and #3 coil, both get spark when tested. Passive resistance tests a bit high on the multimeter. Around 25 ohms.
-New K&N pod air filters.

Its the damndest thing, its just the #2 cylinder that won't fire. I assume that if the coil were bad, both 2 and 3 would not fire. True?

Should I be thinking condenser or regulator at this point?

Thanks,

A

Skonnie Boy wrote:

Simply cannot get #2 cylinder to fire. I've played whack-a-mole as far as fixing cylinders firing and not firing, but here's the rundown on what's been done.

-Replaced all float valves, cleaned all carbs, replaced all gaskets.
-Top end rebuild, adjusted valves, replaced shims accordingly.
-Replaced #2 and #3 coil, both get spark when tested. Passive resistance tests a bit high on the multimeter. Around 25 ohms.
-New K&N pod air filters.

Its the damndest thing, its just the #2 cylinder that won't fire. I assume that if the coil were bad, both 2 and 3 would not fire. True?

Should I be thinking condenser or regulator at this point?

Thanks,

A

Have you tried switching the plug, caps and wires from cylinder #2 to #3 and see if the problem moves?

Caused by one of the following basic problems:
1. Compression (valve clearances, rings, etc.) - compression test?
2. Fuel delivery - is fuel getting into the float bowl? Have you checked float height measurement using clear tube method? Does the spark plug smell like gasoline? Is there an air leak at the manifold causing that cylinder to be extremely lean?
3. Ignition - verified fat blue spark laying the plug against the head to complete the circuit?

It sounds like you have verified ignition. I would suspect fuel, but a compression test is quick and easy to get out of the way. Harbor Freight has a cheap compression tester ( www.harborfreight.com/automotive-motorcy...on-tester-92697.html ). If compression is low a leak down test may be required to find the source of the low compression. Again, Harbor Freight has a cheap and decent leak down tester ( www.harborfreight.com/automotive-motorcy...wn-tester-94190.html ).

Patton will likely chime in with a much better detailed list.

Best of luck!

Still have points and condensers? If not converting to electronic then I would put in new points and condensers.
25 OHMS? Something not right with that maybe your meter was on the wrong scale? Probably 2.5 OHMS.
At Harbor Freight/ "China Tools", they have a in line spark checker for like $5. You can see the spark as it runs. Did you verify the voltage at the coils? Should be within .5 of Battery voltage. Is the plug wet with fuel when you pull it out? If not you may have a stuck float valve/ needle. Try taking out the float drain screw and turning to Prime, should get a steady flow.

Sorry, should have mentioned that a compression test gave me 120 - 125 on all cylinders, might have been a few lbs. less on #2, but not much.

Pulled the #2 plug, and its definitely getting gas. Almost no soot at all after a short test.

Still have points, and I recently gapped them. The points aren't the newest, but they close nicely and I filed them gently to get fresh contact.

Got normal readings for active leads on the coil. I didn't think I needed to change the multimeter setting for testing passive coil resistance. I'll check again, but wouldn't 2.5 OHMS be a bad reading as well?

No room to switch ignition wires, but I could try switching the caps and such. The 2,3 coil is actually taken from a '75 Honda CB750.

Weird, the #2 was firing, until I switched the old valve floats from #3 carb to #2, since #3 wasn't firing. The problem with #2 has persisted since.

So you switched your floats between carbs when you went through them? How did you reset the float level? Measuring with the carb inverted or with the clear tube method?
Filing points oh yea remember that, did you replace the condensers? How did you set the gap? Feeler gauge or dwell meter? Have you gone over your carb intake manifolds for air/ vacuum leaks? What about trying the fore mentioned flow test of removing the drain screw etc?
I think if you check your coil should be about 3 ohm for a points type system, and you may have a resistor in line for the + voltage, lowers the voltage across your points.

Again, I suspect the carbs. Especially since that's what has been changed. Clear tube test would be best bet.

Measured carb floats inverted. Not to belabor the point, but all passages were clear. Only weird thing was a bit of an enlarged opening where the pilot needle emerges into the carb barrel. But, like I said, the #2 has fired before.

I should find someone with the clear tube setup, yes.

Intake manifolds seem to be in good shape. Spraying WD-40 on them while running made no change.

Used a feeler gauge to gap the points. Did not replace the condensers.

It might just be heat conducting from the head, but I swear #2 does fire a bit at higher revs. But not much.

Hey, you're in Madison, Double Dub. Far out, that's my hometown. Here tonight, in fact. Too bad the kz's in Chicago. On, Wisconsin.

The clear tube level test is very easy and only takes about 20 cents worth of tubing. The manual has the proceedure, but you simply attach the tubing to the bowl drain nipple and open the drain while holding the tube up against the side of the bowl and see how far up the fuel goes. The bike should be level while doing this...at least on the center stand. Each carb make has different levels, but the Keihins are usually about 3-4mm below the bowl gasket line.

It's possible for the floats, both brass and plastic, over time to develop leaks. Once a float fills with fuel it is useless. You can usually tell this by shaking the float near your ear and listen for sloshing.

The plastic floats are hollow? Neat, but weird.

What have you used to attach the tubing to the bowl? I have tubing in abundance, just not sure where to find an appropriate attachment.

Here is one of the forum threads on the clear tube method. You might be surprised what the "search forum" box will find.

kzrider.com/index.php?option=com_kunena&...d=3&id=254635#254663

Right, right. Cool idea to use those plastic nozzles. Much easier than sourcing taps with the correct threading.

I'm still a bit confused, though. Even if the #2 carb were overfilling, wouldn't the needle allow about the same amount of fuel into the combustion chamber?

At any rate, I'm 200 miles away from the bike, so I'll just have to wait until next week to try a new round of tests.

Thanks all.