Kat 1100 1989 running rough

[Swampy]

Hello all!

Took the big Kat to the Smoky's for a week with the spouse and ran about 200 miles per day - lots of dragon slaying and skyway running. Great time!

But, on the last day the bike developed a problem. At idle it was rough and seemed to be missing on one cylinder every few seconds. If I kept the rpms above 4000 it had enough power to pull hard and smooth...below 4000 with any kind of load it would bog down and backfire pretty hard.

I pulled the plugs and apparently my mechanic had split fork-like tipped plugs in it and they were very black with carbon.

I replaced the plugs with stock NGKs and it still runs crappy.

Where would you start looking? Next steps?

Thanks!

[Mojoe]

plug wire or coil.

[KYOTE1]

Hello all!

Took the big Kat to the Smoky's for a week with the spouse and ran about 200 miles per day - lots of dragon slaying and skyway running. Great time!

But, on the last day the bike developed a problem. At idle it was rough and seemed to be missing on one cylinder every few seconds. If I kept the rpms above 4000 it had enough power to pull hard and smooth...below 4000 with any kind of load it would bog down and backfire pretty hard.

I pulled the plugs and apparently my mechanic had split fork-like tipped plugs in it and they were very black with carbon.

I replaced the plugs with stock NGKs and it still runs crappy.

Where would you start looking? Next steps?

Thanks!

by chance did you get some bad gas, just trying to rule things out.

when was the last time the carbs were clean and set.

[Swampy]

Last time was probably 5 years ago - plugs are fairly recent. I run it a few times a month so the fuel should be relatively healthy.

I'll check coil/plug wires visually but not sure what I am looking for otherwise.

any hints appreciated.

[Swampy]

Cleaned out carbs, replaced air filter and plugs., and replaced the battery since she was 18 months old and I tend to eat them on this bike....wont start. I figure it must be spark problem.

Should I upgrade the Denso's that are on there to something else? Katana 1100 1989.

Denso L29700-147012V
33410-481300

What are your thoughts? Suggested sources for them?

Thanks!

[Paolo]

..did you try change the wife.?





\
.... just kidding

[Swampy]

hehehe

[Swampy]

that would cost me half my stuff - not a good business decision

[Paolo]

...she wouldn't take the kat running rough at least...

[NiteMare]

grab a seperate fuel supply so you can lift the tank off and run it in the dark, you're looking for sparks/tracking on the coils, plug leads, plug caps(don't forget to plug the vacuum pipe) ....

check your intake boots for cracks, spray carb cleaner on them at idle (or misfire range) ....

did you check the carb diaphragms for splits ??

check the low tension terminals on the coils for cleanliness/security

check the cdi terminals for cleanliness/security

when was the last time you checked your valve gaps?? how many miles ??

those are probably the best hints i can give towards solving your problem, hope it helps

p.s.
sell the wife, the new owner wouldn't want your stuff

[TheHayabusa]

Yeah, do what NiteMare said.

If your valves have not been adjusted in a long time that would make it start to run like crap after a long period of great performance.

Fuel, air and spark are all you need to get your bike running. Pull the plugs, leave them in the wires and set them on the head somewhere and turn the engine over to see if all 4 are sparking. Clean synchronized carbs with un-kinked fuel lines and a petcock that does not have a vacuum leak will cover 95% of your fuel issues. Air is self-explanatory.

I wouldn't waste your money on buying new coils, they rarely go bad. I would just check your connections and make sure your plug wires are seated in the boots.

[KYOTE1]

The same just happened to me. read on

Hello all!

Took the big Kat to the Smoky's for a week with the spouse and ran about 200 miles per day - lots of dragon slaying and skyway running. Great time!

But, on the last day the bike developed a problem. At idle it was rough and seemed to be missing on one cylinder every few seconds. If I kept the rpms above 4000 it had enough power to pull hard and smooth...below 4000 with any kind of load it would bog down and backfire pretty hard.

I pulled the plugs and apparently my mechanic had split fork-like tipped plugs in it and they were very black with carbon.

I replaced the plugs with stock NGKs and it still runs crappy.

Where would you start looking? Next steps?

Thanks!

Get this,
I pulled the plugs they were fine,
I checked the coils with a metre and they were fine.

Perplexed, I put the tank back on and the seat still off , started the bike and listened and observed it running rough and missing as you described.

For what ever reason I wiggled the battery cable forwarded and it died.
Tried to start it, no-go.

Moved the cable back and it ran fine with no roughness and missing.

Inspected the cable and found it a bad connection with corrosion, all connections were tight as well.

[Swampy]

bike has 23k, vlave job by pros at 18k...been running great ever since.

Lost spark due to corroded wires in the starter - on/off switch. Took it aprt but it was bad - replaced it and now have spark accross all plugs.

Tried starting it with choke and without, gas open and closed, clutch lever in and out, kickstand up and down....it turns but doesnt light and I do smell gas at the carbs.

What next?

[Swampy]

So charged battery (it is new but I had worn it down testing) and she fired up but very rough and needs about 2000 rpm to keep alive. Since I have tank mounted without the airbox etc, I srpayed carb cleaner in the carbs while it ran.....sputters and backfires. Doesnt sound good at all.
Checked to see if plug wires are in right order - checked all connectors. I think I am going to replace a bunch of the connectors on and around the battery - they all seem old, crunchy, and show signs of corosion.

Open to ideas!

[KYOTE1]

like i said i had the same problem and replaced wires until I got to the one that caused it .

The two wires from the signal generator off the crank. these wires and the connector are behind the left side cover forward of the battery under the carbs, the connector had a bad fit and the vibrations while running caused intermintant connection making it run rough

Fixed this connector and never had the problem again. Look for the same on yours.

Good Luck