Only firing on 3 cylinders

bromz
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1981 kz1000 csr

12 May 2013 15:06 #587034 by bromz

Only firing on 3 cylinders was created by bromz

Where do I start. Number 2 stays cold on a fresh start till others warm it up. Could it just be a plug wire cap?

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Motor Head
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FIX UP YOUR BIKE RIGHT AND CHEAP

12 May 2013 23:39 #587111 by Motor Head

Replied by Motor Head on topic Only firing on 3 cylinders

Check your carb holders/ intake manifolds for leaks. Also #2 would be hooked to the vacuum petcock. Make sure its hose is connected tight, not cracked etc.
Have you checked the compression? Do the Carbs still have the metal cap over the pilot/ low speed mixture screws?

1982 KZ1000LTD K2 Vance & Hines 4-1 ACCEL COILS Added Vetter fairing & Bags. FOX Racing rear Shocks, Braced Swing-arm, Fork Brace, Progressive Fork Springs RT Gold Emulators, APE Valve Springs, 1166 Big Bore kit, RS34's, GPZ cams.
1980 KZ550LTD C1 Stock SOLD Miss it
1979 MAZDA RX7 in the works, 13B...

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Patton
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12 May 2013 23:59 #587117 by Patton

Replied by Patton on topic Only firing on 3 cylinders

Got good spark on #2 plug?

Got good compression on #2 cylinder?

Valve clearances within spec on #2 cylinder?

Good Fortune!

1973 Z1
KZ900 LTD

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martin_csr
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13 May 2013 09:19 #587140 by martin_csr

Replied by martin_csr on topic Only firing on 3 cylinders

Redo the spark plug wire connections at all points from the coils to the plugs. Unscrew the ribbed compression boots & untwist the wires. If there's a lot of the white crusty oxidation, nip off the ends of the wires a tad but not too much. I solved an intermittent firing problem by doing the above but have since installed new Dyna coils & spark plug wire set.

1981 KZ650 Competition Sports and Road

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bromz
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1981 kz1000 csr

13 May 2013 17:37 #587209 by bromz

Replied by bromz on topic Only firing on 3 cylinders

I swapped plugs from one to two, swapped plug caps from one to two redid all ends and connections. The plug on 2 was a little fouled so cleaned it up. From a cold start 2 seems to be warming up just slightly behind one. Not sure if its heat from one or not its that close. Bike sure seems to be running fine down the road(he screams!) i can't believe it's missing a cylinder running that well am I over thinking this?

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bromz
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1981 kz1000 csr

13 May 2013 17:38 #587210 by bromz

Replied by bromz on topic Only firing on 3 cylinders

One of my caps doesn't ohm to 5 k it's way above that. Do I need to replace it or coul that be my issue?

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Motor Head
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FIX UP YOUR BIKE RIGHT AND CHEAP

13 May 2013 21:58 #587245 by Motor Head

Replied by Motor Head on topic Only firing on 3 cylinders

A bad plug cap will cause a miss-fire. Your coil actually fires two plugs at the same time. Each betting part of the secondary loop, so if one is bad it'll end up effecting two.
Up to you, either all new or just do wires and caps. New coils would be best.

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bromz
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1981 kz1000 csr

14 May 2013 12:24 #587347 by bromz

Replied by bromz on topic Only firing on 3 cylinders

ok im gonna start with the wires first. I will replace the coils but am going to try to wait till i get back from vacation in june. can I use dynatek dw300 7mm silicone copper core wires with the caps that come on them? or do I need to put my existing caps on in wich I would have to replace one of them

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Spectre1982
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17 May 2013 20:51 #587989 by Spectre1982

Replied by Spectre1982 on topic Only firing on 3 cylinders

I think those are the same wires I got. The new caps will work. Don't use the old ones.

1982 Kawasaki KZ750 Spectre

1978 Kawasaki KZ200

1985 Yamaha XV1000 Virago

(Avatar picture is from Alleycatscustoms.com)

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bromz
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1981 kz1000 csr

20 May 2013 13:24 #588344 by bromz

Replied by bromz on topic Only firing on 3 cylinders

Well I put new resistive plugs in and new dyna dw 3000 wires and I still think number 2 is heating up a little behind the other cylinders. Outside of pulling 2s plug and making sure i have spark could this problem be carberation?

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Spectre1982
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22 May 2013 00:23 #588659 by Spectre1982

Replied by Spectre1982 on topic Only firing on 3 cylinders

It's possible it's a carb issue. I would check for vacuum leaks and check engine compression. Also, measure your valve clearance and write your numbers down.

There's only so many things it could be. Go down the list and you'll get it fixed.

1982 Kawasaki KZ750 Spectre

1978 Kawasaki KZ200

1985 Yamaha XV1000 Virago

(Avatar picture is from Alleycatscustoms.com)

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bromz
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1981 kz1000 csr

25 May 2013 10:21 - 25 May 2013 10:22 #589119 by bromz

Replied by bromz on topic Only firing on 3 cylinders

So I pulled number 2 plug grounded it to frame and i had a nice blue spark. Second time I tried it no spark Third time no spark, Fourth time I had spark. So coil? I have already posted I have changed the plugs and wires so they are all new. So I think I am running on about 3 and 1/2 cylinders. What do you guys think?

Last edit: 25 May 2013 10:22 by bromz.

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Only firing on 3 cylinders

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