What does this mean!?!?

  • treitz
  • treitz's Avatar Topic Author
  • Offline
  • User
  • Posts: 206
  • Thanks: 2

What does this mean!?!?

28 Mar 2013 21:15
#579344
Bike is running well (not acting rich or lean) but my plugs are still telling me its rich.
1979 KZ400 - 2-1 Manifold - Mikuni VM34

Please Log in or Create an account to join the conversation.

  • undiablo
  • undiablo's Avatar
  • Offline
  • User
  • Posts: 436
  • Thanks: 64

Re: What does this mean!?!?

28 Mar 2013 22:13
#579352
May be you should try a hotter spark plug.
Kawasaki KZ 750/4 LTD 1981
Kawasaki KLR 650 2011
Argentina - Buenos Aires

Please Log in or Create an account to join the conversation.

  • taildragger1197
  • taildragger1197's Avatar
  • Offline
  • User
  • Posts: 113
  • Thanks: 16

Re: What does this mean!?!?

28 Mar 2013 22:47
#579359
Dirty air cleaner
Leaving choke/enricher on too long
Excessive time idling
Pilot jets too big/screws not adjusted correctly

Take the bike for a 10 mile ride at highway speeds then check your plugs. NOT after you have just started it up and have been idling.
Union City, Tennessee
1979 KZ1000 LTD B3
1979 KZ1000(1260)LTD S/G Pro ET
1993 ZX11 D1 Ninja

Please Log in or Create an account to join the conversation.

  • Patton
  • Patton's Avatar
  • Offline
  • KZr Legend
  • Posts: 18640
  • Thanks: 2100

Re: What does this mean!?!?

28 Mar 2013 22:52
#579365
treitz wrote: Bike is running well (not acting rich or lean) but my plugs are still telling me its rich.
Valve clearances within specs?
Fat blue sparks visible on plugs?
Ignition timing spot on?
Advancer functioning properly?

Over-rich mixture from carb (for whatever reason).

Good Fortune! :)
1973 Z1
KZ900 LTD

Please Log in or Create an account to join the conversation.

  • 893cv
  • 893cv's Avatar
  • Offline
  • User
  • Posts: 201
  • Thanks: 15

Re: What does this mean!?!?

28 Mar 2013 22:57
#579367
You may need to check the voltage at the ignition coils. It needs to be the same as battery voltage. If it is low, clean all of the connections between the battery and the coils. The kill switch on the handlebars and the main (key) switch are problem areas due to being exposed to h2o. When the ignition system is operating with full voltage you will not see any soot on the plugs.
I have installed the "coil mod" on all of my bikes. You can do a search for more information.
1980 kz1000 LTD
1978 Z1R

Please Log in or Create an account to join the conversation.

  • treitz
  • treitz's Avatar Topic Author
  • Offline
  • User
  • Posts: 206
  • Thanks: 2

Re: What does this mean!?!?

28 Mar 2013 23:15 - 28 Mar 2013 23:17
#579372
I did the coil mod already.

I'll check the other things you guys suggested.

I'm hesitant to take it on a long ride for fear that I'll burn my plugs up running rich for whatever reason.

My compression is low, could that be the cause?
1979 KZ400 - 2-1 Manifold - Mikuni VM34
Last edit: 28 Mar 2013 23:17 by treitz.

Please Log in or Create an account to join the conversation.

  • Patton
  • Patton's Avatar
  • Offline
  • KZr Legend
  • Posts: 18640
  • Thanks: 2100

Re: What does this mean!?!?

28 Mar 2013 23:38
#579377
treitz wrote: I did the coil mod already.
I'll check the other things you guys suggested.
I'm hesitant to take it on a long ride for fear that I'll burn my plugs up running rich for whatever reason.
My compression is low, could that be the cause?

burn my plugs up running rich
-- not likely, but might foul them out.

My compression is low, could that be the cause?-- Yes, but sometimes resolved by adjusting valve clearances to specs.

Would pull the plugs and look for fat blue spark while spinning the engine. Plugs will be otherwise connected as usual, and held grounded against the engine head. Ignition must be switched ON.

Good Fortune! :)
1973 Z1
KZ900 LTD

Please Log in or Create an account to join the conversation.

  • Patton
  • Patton's Avatar
  • Offline
  • KZr Legend
  • Posts: 18640
  • Thanks: 2100

Re: What does this mean!?!?

28 Mar 2013 23:40
#579380
Did adjusting the valve clearances improve compression?

What is visible quality of the spark?

Good Fortune!:)
1973 Z1
KZ900 LTD

Please Log in or Create an account to join the conversation.

  • treitz
  • treitz's Avatar Topic Author
  • Offline
  • User
  • Posts: 206
  • Thanks: 2

Re: What does this mean!?!?

28 Mar 2013 23:43
#579381
I tried adjusting my valves but couldn't figure it. Still working on that.

I'll check the quality of my spark tomorrow.
1979 KZ400 - 2-1 Manifold - Mikuni VM34

Please Log in or Create an account to join the conversation.

  • treitz
  • treitz's Avatar Topic Author
  • Offline
  • User
  • Posts: 206
  • Thanks: 2

Re: What does this mean!?!?

31 Mar 2013 11:45
#579782
Valves are correctly set.

Reset timing to factory settings.

Getting good spark.

Retested compression and its not low after all! So happy.

Plugs are still black.

I guess it's back to jetting?
1979 KZ400 - 2-1 Manifold - Mikuni VM34

Please Log in or Create an account to join the conversation.

  • Patton
  • Patton's Avatar
  • Offline
  • KZr Legend
  • Posts: 18640
  • Thanks: 2100

Re: What does this mean!?!?

31 Mar 2013 13:24
#579800
As suggested by taildragger1197, check for dirty air cleaner.

If not already done, would next perform clear tube tests, to verify the service fuel level. If too high, will overly enrichen carb circuits

What carb cleaning has been recently done?

Good Fortune! :)
1973 Z1
KZ900 LTD

Please Log in or Create an account to join the conversation.

  • baldy110
  • baldy110's Avatar
  • Offline
  • User
  • Posts: 2272
  • Thanks: 512

Re: What does this mean!?!?

31 Mar 2013 17:20
#579829
You are putting in new plugs every time you read them right?

Please Log in or Create an account to join the conversation.

Powered by Kunena Forum