Air filter question

[max]

When I open up my air box, I see a gap between the top of my air filter and the air box. There's only one little screw that holds this thing in place, and when totally screwed in there is about a 1/4 inch space all around for air to suck up. I looked on my local junkyard's fiche and they show no gasket on top of the air filter assembly. I'm going to try and make one out of a sheet of rubber because I know that there should definately be no gap, but my question is this: should there be a gasket here, and could this condition be the cause of my bike dying under 2000rpms and having low end torque loss?

Thanks,
Max

[chiphead]

Should be gasket there and lack of one could contribute to the run-ability issues you described.

[49er]

When I open up my air box, I see a gap between the top of my air filter and the air box. There's only one little screw that holds this thing in place, and when totally screwed in there is about a 1/4 inch space all around for air to suck up. I looked on my local junkyard's fiche and they show no gasket on top of the air filter assembly. I'm going to try and make one out of a sheet of rubber because I know that there should definately be no gap, but my question is this: should there be a gasket here, and could this condition be the cause of my bike dying under 2000rpms and having low end torque loss?

Thanks,
Max

There should be a strip of medium density sealing rubber about 4mm thick, between the filter and the mounting surface. Without it, your engine will ingest any dust and dirt drawn into the airbox. The lack of sealing in this area will also cause the engine to run lean, especially in the lower rev range.

[BassCliff]

I had the exact same problem with my airbox (1980 GS850GT). The 27 year old original gasket material on the "roof" of the airbox was long ago rotted. I got some 3/8" thick, dense spongy weather stripping type material from the HVAC shop at work. It was peel-off sticky on one side. I had to trim it to fit, but I used it on the top of the air filter frame and around the airbox side covers. From what I understand there are only a few places where the airbox should be letting air in, a couple of vents on the bottom and a "snorkel" on top somewhere?

My air filter now fits pretty snugly in the airbox. Since I put it on top of the air filter frame and not the bottom of the intake inside the airbox it will have to be replaced periodically as it wears from removal/installation when cleaning the air filter. But I think it's easier to take out the air filter frame, remove/replace the air filter, and clean/replace the weather stripping on the frame rather than stand on your head and reach inside the airbox to remove/clean/replace gasket material there. I've also heard that removing the airbox is quite a chore.

Good luck making your gasket! All the best to you and yours.

Thank you for your indulgence,

BassCliff

[argonsagas]

Weather stripping works well for this purpose.

A warning is in order, which is that the foam used for this is not compatible with gasoline. It will melt and/or break up.

If you ever have a fuel spill that gets back to the filter, be sure to replace the foam before starting the bike again, as the carbs will not like the foam at all.

[bwringer]

Weatherstripping your airbox and air filter is a rite of passage for GS850 owners.

Welcome!

Smear the face of the weatherstripping with some grease to make it easier to install and remove without tearing the foam. I also like to use weatherstripping cement to make sure the edges of the foam pieces stick together.