82 750 Spark Plugs

[Guest]

My #1 and #4 plugs are the same color; they show a good normal burn. #2 and #4 are also the same but they are a bit darker in color. And the answer is?????????????????

Thanks

[cowboyup3371]

I think they are good depending on how much darker. Are you having problems with how the bike is running?

[MisterCinders]

How do you have 2 plugs for No. 4? :P

If 2 and 3 are significantly darker, then you should check the mixture settings on those carbs. With those paired results, you also want to check the ignition timing and coils. If the 2/3 coil or timing is off, it can show up as rich/lean plugs.

[Nessism]

My #1 and #4 plugs are the same color; they show a good normal burn. #2 and #4 are also the same but they are a bit darker in color. And the answer is?????????????????

Thanks

Magic 8-ball says you need to do some maintenance.

[BassCliff]

Hi,

Perhaps you were comparing #1/#4 with #2/#3?

If so, the symptom could be caused by one or more issues:

Petcock leaking
Idle Mixture Screws maladjusted
Spark Plug Caps out of tolerance
Corroded connections causing extra resistance
Coil going bad

What voltage are you getting at the coils? Have you swapped the coils to see of the problem follows the coil? Are the carbs really clean? Is the air intake system free of leaks? How are the idle mixture screws set?

Mr. Nessism is right. Maintenance is necessary. Sometimes it's a process of elimination. The idea is to keep all of the systems in proper working order, spark, fuel, compression (electrical/ignition, carbs/intake, valves).

Thank you for your indulgence,

BassCliff

[mret430]

Thanks. Direct me to the idle mixture screws if you don't mind.

[BassCliff]

Hi,

Thanks. Direct me to the idle mixture screws if you don't mind.

You'll find all kind of carb procedures, guides, and pictures on my website.

Thank you for your indulgence,

BassCliff

[Steve]

Thanks. Direct me to the idle mixture screws if you don't mind.

.

[mret430]

thanks. is it true that on my 82 and anything after 79 that you could not adjust factory settings? If not, whats the best way to adjust idle screws so all are in sync?

Thanks again

[BassCliff]

Hi,

is it true that on my 82 and anything after 79 that you could not adjust factory settings?

The factory installed caps on top of the idle mixture screws so that the end users could not make adjustments that would modify the emissions. That caps can be removed so that you can make the proper adjustments. To learn the proper way to remove the caps and clean your carbs, see this guide by Mr. Nessism:

Mikuni BS(CV) Carburetor Rebuild Tutorial

If not, whats the best way to adjust idle screws so all are in sync?

The idle mixture adjustment is a separate procedure from a carb vacuum synchronization. The idle mixture screws adjust the amount of fuel/air mixture the cylinders receive at idle from the idle circuit in the carb. All four should be balanced so that the engine idles smoothly.

The carb sync ensures the butterfly valves and slides are all open the same amount at higher engine speeds. Again, all four should be balanced so that each cylinder is doing the same amount of work, letting the engine run smoothly at higher revs and taking away the "buzzy-ness". See the following:

Plug Chops-Highest RPM Methods

(Note that the above method starts with the screws set a little low and you adjust the idle up to the "highest idle". You can also start with the screws 3 turns out or more and screw them in until the engine speed decreases, then back out a quarter of a turn or so.)

Synchronize Carburetors
(With the Morgan Carbtune)

You will find most of the answers to common questions and tutorial guides for most common repair and maintenance procedures on my little website. Feel free to stop by. It could save you a lot of time and effort.


Thank you for your indulgence,

BassCliff