Hotter plug on '82 gs650

[Anonymous]

I have been having plugs fouling pretty quickly in all 4 cylinders. I have been using ngk D8EA spark plugs. I would like to try hotter plugs to see if it helps with the carbon build up on the plugs. I am aware that a hotter plug will only mask an issue in the carb's or bad combution, but want to try it as a trouble shooting step. I guess my question is what number would you suggest for this purpose? A d7ea or a d6ea? Is a 6 too hot perhaps? Any suggestions would be helpful.

-Brad

[Rico]

First off I would like to hear from the smart guys here @ GSR about this also.
With that said, I've been running the B7 instead of the B8 for 3k miles.
The reason way is because of a rich condition I've been chasing sence I got the bike. It runs great! just rich (even on all 4) and I don't want to break into the carbs for this.

ANYWAY, the B7 seems to have fixed this a bit along with a new filter and tuning the baffle in my pipe.
But If I'm doing something wrong please let me know.


rico

[Anonymous]

Rico - I'm curious - with the hotter plug are you spark plugs not fouling out and getting covered in carbon (as mine are)? Also, with the colder plug, how soon were they fouling? 50 miles, 500 miles?? Mine seem to go pretty fast, maybe 50-75 miles. The bike keeps running ok (some slight performance decrease over time) for awhile after that, but to get the full performance back I have to either clean them off or replace them.

[duaneage]

Re: Hotter plug on '82 gs650

I have been having plugs fouling pretty quickly in all 4 cylinders. I have been using ngk D8EA spark plugs. I would like to try hotter plugs to see if it helps with the carbon build up on the plugs. I am aware that a hotter plug will only mask an issue in the carb's or bad combution, but want to try it as a trouble shooting step. I guess my question is what number would you suggest for this purpose? A d7ea or a d6ea? Is a 6 too hot perhaps? Any suggestions would be helpful.

-Brad

You should only go with hotter plugs if

1. You run the bike for short trips and it does not have a chance to warm up properly.

2. Very cold weather driving, although not with high speed operation.

Find out why it is running rich. Fix that rather than inject another variable into the equation. Check the air filter, replace if necessary. Check the spark output from the coils by removing a plug and grounding the base. If you see a weak orange spark, bingo. Sould be bright blue and very active. Check that the gap is correct as well. Maybe the 23 year old coils are weak and fouling the plugs. Using a hotter heat range will not make up for a weak spark, it will just make the plugs hotter and probably cause ignition knock.

check the float levels. Should be around .81 inches from the gasket surface to the float bowl tab. This does require removing carbs but that will give you a chance to replace the o rings in the intake boots.

[chuckycheese]

Hot

A very experienced bike mechanic in my town told me using hotter plugs is almost never necessary and that you can REALLY screw up your bike doing it. This guy is pretty sharp and I'll bet he's right.

[vstan905]

Going from an 8 to a 7 is not much of a change so I see no probem with it. It won't hurt anything. Still, you should find out why the bike runs rich.

[Anonymous]

Going from an 8to7 is ok per the shop manuel 1982 GS1100. IT says go to that plug if you have "wet plugs".

[KEITH KRAUSE]

I'd do as "duaneage" says. Except under the two conditions the factory manual describes, you should never need a hotter, or colder plug.
With a new plug, check the quality of the spark and check timing too with a gun, both idling and fully advanced. Check that the plugs are gapped correctly.
If all that's good, and the air filter is clean, focus on the carbs.