Airbox Sealing

[mbopp]

There are many references to this process on the forum, but was wondering if I could get some complete info on this topic.

I have an GS850G '81. I just ordered a new air filter, and I want to install it and seal up everything just right. What should I inspect, use, and do during this process?

Also, the left rubber gasket is missing under the chrome cover. I don't see this as an order able part, Is there a good alternative replacement for this?

I understand that weathersealing is part of the process. Any additional info on the details of that would be helpful.

Thanks!

[chuckycheese]

Filter

By far, the most important seal is the one between the air filter and the entrance into the carbs. I don't think it's possible that any more or any less air will enter regardless of where else it's available.

In other words, if there is one hole in the air box or 3 holes, the same amount of air will pass through the filter. The only way that wouldn't be true would be if the hole was so small as to be restrictive. On mine, it's plenty big enough to get all the air it 'wants' through the primary opening.

[ironsheik]

Well I just did this and there's a bunch of good info here but nothing all in one place so here's what I did. First, buy yourself a roll of 5/16" or 1/4" thick foam weatherstripping with the sticky back at a hardware store. I bought 1" wide and cut each piece down to 1/2" wide. You'll first need to pull out the airfilter and pull off the foam that is stuck to the bottom of the box on top of the filter housing. I imagine it's pretty dry rotted and falling apart. Regardless, it's probably lost most of it's sealing so rip it out and clean all the leftover gunk off. I just used some Windex and cleaned up the whole box.

I would also remove the metal covers on both sides and reseal the rubber covers underneath to the airbox with some yellow weatherstripping adhesive from an autoparts joint. There's a thread somewhere on here where someone mentions a good way to reseal a box which is missing this rubber so do a search for that. Or you could stick the weatherstripping to the inside of the metal cover to seal around the edges of the box. This ought to work pretty well but maybe not enough for the top portion. I did this to the bottom portion where the rubber had ripped off. After all this, you'll probably have a better running bike. I sure did! Good luck.

Josh

[chef1366]

By far, the most important seal is the one between the air filter and the entrance into the carbs. I don't think it's possible that any more or any less air will enter regardless of where else it's available.

In other words, if there is one hole in the air box or 3 holes, the same amount of air will pass through the filter. The only way that wouldn't be true would be if the hole was so small as to be restrictive. On mine, it's plenty big enough to get all the air it 'wants' through the primary opening.

One of the old cheap mods on these bikes was to up the main jet and remove the airbox lid. It did flow more air.:-D

[chuckycheese]

One of the old cheap mods on these bikes was to up the main jet and remove the airbox lid. It did flow more air.:-D

I just looked up the schematic for his bike..and I can see what he means. It's a way different set-up than the ones on the Gs750s. I think on ours, the only possible way to get more air flow is to either modify the filter....or bypass it because there is really no restriction on the air already available to the outside of the filter. (If there were, the intake air hole would suck like a vacuum cleaner...and I don't think it does.)

[mbopp]

The missing rubber on air box cap

Well, I've searched around the forums a bit and am not seeing a thread on what to do in the event of a missing rubber gasket under the cap of the airbox. Can someone help point me in the right direction?

Thanks!

[ironsheik]

Just needed to look around a little. Almost all the answers to your questions can be answered by doing searches on the forum. In any case, here's the link:

http://www.thegsresources.com/_forum/showthread.php?t=87873&highlight=silicone+airbox

About 6 posts down...

Although after reading the silicone method, I think weatherstripping under the metal side covers is going to work better than silicone. Good luck.

Josh

[49er]

By far, the most important seal is the one between the air filter and the entrance into the carbs. I don't think it's possible that any more or any less air will enter regardless of where else it's available.

In other words, if there is one hole in the air box or 3 holes, the same amount of air will pass through the filter. The only way that wouldn't be true would be if the hole was so small as to be restrictive. On mine, it's plenty big enough to get all the air it 'wants' through the primary opening.

Yes, it is important that the filter to airbox housing sealing strip completely seals. But it's equally important to completely seal the top portion of the end caps as well. If this area leaks, you will be drawing some unfiltered air directly into your engine. This will also cause your mixture to be too lean.
Follow the directions in ironsheik's link. The old rubbers swell after 25years of use anyway and leak.
I cut and reshaped my old rubber seals and used F2 Ados contact adhesive to attach them to the airbox steel rims.
With missing one seal, you need to follow the weathering strip method.

[mbopp]

Weatherstripping steel end caps

Forgive me for being slow, but I wanted to clarify the weather stripping method for sealing things off when the rubber seal is missing.

Should I be sticking the weather stripping to the metal itself in the correct spots? (around the edges and one across the middle). Will this be enough to seal it tight?

[ironsheik]

I assume that would be the best way but I haven't had to do this exact step myself. My rubber seals were sufficient on the top portion. I would think 5/16" or 3/8" thick weatherstripping ought to seal pretty well though...

Josh

[rustybronco]

visual aids...

[AkumaKuruma]

i just sealed mine up. i can almost launch the bike now but my top end went from 5000 to 4000 (i have other issues with the bike). i noticed my 2 left side velocity stacks were almost popped off the bottom of the carbs, those will be my next things to fix. too many issues with my bike but at least it runs for a basic commuter.