Air Filter Question

[Anonymous]

Hey everyone,
I'm new to the forum....just purchased a 1982 gs1100g as my first bike. Previously owned a 81 750E, but never got it going. I don't know much about engines, but can learn with a little help. My bike has been surging when I get on the throttle, or when I have been riding for a long distance. I have searched the forums, but haven't found what I was looking for. When I purchased the bike, the previous owner didn't have any service records.
I changed the plugs, but they fouled after 150 miles of city/highway driving. Two were dark black, and two looked normal. Is this from air/fuel mixture, or what?
I checked the air filter, it was dirty and obviously needs to be replaced, but it spells like it has been soaked in gasoline. Is this normal?
As for the surging, it has been doing it mostly around 4000 rpm in 3rd or 4th gear when I am accelorating. Bike will stall after surge when being rode longer distances (30-100 miles at 4500 rpm in 5th gear)
Any help is greatly appreciated.
I talked to my uncle about the surging problem, (he's a hardcore kawasaki man), he thought maybe the rings were bad, and I could be losing compression. I know the possibilities are endless, but need a direction to start.

Thanks,
David

[earlfor]

Surging is usually a tuning problem (a combination of fuel and airflow). Its possible it could be an electrical problem such as a faulty wiring connection or ignition timing, but I dont think probable. More likely, it is a carb setup and mixture problem. Before making any changes to mixture settings, float levels or jetting, I would get a set of vacuum guages and synch the carbs. Its impossible to accurately work on any of those things if the carbs are not in synch. Before doing the carb synch though, you must have an airfilter that is in good condition and flows as it should be flowing.

No, soaked with gas is not how an airfilter element should be. An airfilter soaked with gas indicates (at least to me) that either the petcock is not shutting off and allowing gas to seep when the engine is not running, or the float needle valve "O" rings need replacement which will result in the float bowls overfilling and flooding things. I suspect you have both problems because if the petcock is not leaking gas, there will be no excess going to the float bowls to leak. If the petcock leaks and the float needle valves are shutting of fuel as they should, then no fuel should be able to get to the airbox. For there to be fuel in the airfilter/airbox, both have to be faulty. Also, consider the airbox/airfilter is on the intake side. Fuel does not flow upstream when the engine is running, so your gas soaked filter problem stems from when the engine is not running.

You can get the "O" rings for the carbs from Robert Barr. His site is at

http://www.cycleorings.com/

A complete set of "O" rings for four carbs is $12. (considering you also have a mixture problem with your carbs, I think it advisable to replace all the "O" rings in your carbs anyway. It will save you "chasing your tail" when sorting out your mixture problems and for $12.00, its a great buy.
Robert did a good job with those "O" ring kits. They work flawlessly. :-)

Earl

[Poot]

I'll second the motion for the carbs....


The carbs are definitely out of synch, since 2 plugs wore different than the others.

Also, check your idle-speed adjuster knob (located under the carbs, in the middle, slightly to the back) although youd probably notice it by idling really high.

you should look for an idle between 950 and 1050 rpms (so say suzuki)

you might as well take care of the carbs after you take compression readings though, since you will then be guaranteed that they are clean.

[Anonymous]

Thanks for the info, I'll be sure to get on that first thing this weekend and let you guys know what happens.

Dave