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Ok been having this problem for some time and it's getting to the point, that if I can't fix it the bike will be broke up and sold.

So, the problem.

gsx1100f engine in katana with gsxr38mm carbs. 

it runs grate but on a random basics it will stop running on one cylinder, after you turn the engine off. Can be any cylinder 1,2,3,4 take the plug out and it's wet, put another plug in runs on all 4 cylinders and will stay running with no problems for the next hours, day, weeks etc once it's running on all 4 it will stay running on all 4.

only seen to drop a cylinder once the ignition has been turned off but not every time and not always the same cylinder.

I've replaced the HT leads (dyna coils and leads) swapped the carbs, tried different plugs and different make of plugs (Not got about 6 new sets that I've tried lol)

So Any ideas?

Like I say if not I'm going to break the bike, as I won't sell a bike with a problem.

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11 hours ago, gsxwill said:

Had same problem with gsx 1100 f many years ago, changed pick up as a last throw of the dice and it sorted it, so hope it does the same for you! 

Much too nice to be broken up(y)

Mind you, i am still convinced  all these years later it was an earthing issue, 

God i hated that bike, even more than my ts 50xD

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40 minutes ago, gsxwill said:

Mind you, i am still convinced  all these years later it was an earthing issue, 

God i hated that bike, even more than my ts 50xD

the bandit's suffer with an earthing problem sometimes as well, its normally the spade connector on the thickish wire thats connected to the main battery earth, causes some weird shit O.o 

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Ok, had a look at the Kat today, this time not running on number 4 cylinder. Fuel at carbs but Number 4 down pipes cold.

when I lifted the plug cap just off the plug,(not all the way off, just off the top of plug. Green dyna coils with new dyna ht leads ) it started to run on that cylinder and now on all 4 cylinders O.o

So, before now I've bathed the carbs, then change the carbs, start of this month replaced the ht leads.

It's had this problem for about 1 year, sometimes can go to the bike start it up and it runs sweet, then I can start it 20 mind later and it will not be running on one of the cylinders without even riding it O.o

Any ideas why it is doing this???

I've got a set of standard coils,leads and caps coming, so I will swap them and see if it does anything.



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Very strange problem mate.

Are you using resistor type plugs?

If it runs well 

When starting to remove it may be the extra resistance making the difference or it could be nothing to do with it but would be clutching a straws by now lol

Edited by Fazz711
Fat fingers
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Just standard plugs.

Bandit coils/leads/caps have arrived today, so just having a coffee, then into the garage to swap them over.

I've found two CDI from the gsxr1052 with pickups, also found harness from a gsx600f, CDI from a gsx750f and b6 pickups, harness from a b6 MK2, that's without using bits off any of the project bikes, so should be able to sort the wiring if needed but one thing at a time lol

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Well, not the coils :(

Good spark on all 4 cylinders but number 4 won't run, change the plug, first push on the start button and all 4 cylinders run sweet O.o but I know (think, if it does the same as it has been) it will drop a cylinder and not always the same one.

So the next step, is to remove the dyna2000. Only problem, I can only find one of the CDI plugs on the harness and it's been that long since I first built it I can't remember what I did xD so I'm going to have to start cutting the tape off the harness to find the wires :| hayho.

If only it was always the same cylinder xD

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You are looking at electrics 'because it must be electrics - right!' Wrong, you've shown that you can get good reliable sparks that drop randomly across any cylinder so that would indicate the ign. system is functional. You changed the plugs and it runs on four . . . . . . a fouled plug often won't work! This points to carbs over fuelling IMO? It doesn't sound massive amounts but enough to foul a plugs in a random fashion unlike one cylinder always goes out due to a leaky float valve for example!

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@Gixer1460 I quit agree with you but I've had the same carbs and carb settings on this bike since I first built it and it's ran fine for the last 15 ISH years and it's only been doing this for the last year.

I've cleaned the carbs, gave them a good going in the bath and put a new carb kit in them, still did it, I've changed the carbs and carb inlet rubbers to a set of b12 Dyno tuned carbs on, still did it.

The bike can run fine for days/weeks then one cylinder will go down but at the same time I can start it up in the garage (to make sure it's running before I go out) take it out front put my jacket etc on restart it and it could just run on 3.

The carbs where my first thought as well.

I've even change the carb settings to make them run a bit leaner and apart from it not running quiet as well with pickup etc, it still did the same thing.

There's no harm in changing the pickups and CDI. If that doesn't work, well back to square one xD

At lest the bike looks good :D

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16 minutes ago, Fazz711 said:

Did it start after you put the some new plugs in? 

If you need any proper harness tape give me a pm and I will pop some in the post. 

I have lots at the moment. 


Yes, if I change the plug on the cylinder that's not running, it fires up first press of the start button. 

Thanks got some (y)

I was thinking at the start it was carbs, as the plugs are on the black sutty colour with a tan center

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