Airbox sealing and boot installation

[Roostabunny]

Hey all -

I spent an hour or two yesterday cleaning up and tightening up the airbox on my '81 GS850G. Weatherstripping and a razor were key. I'll post pics of the job a little later, but in the meantime, I'm confused about something.

The '81 GS850 has left and right-hand boots, and I can see that they're slightly asymmetrical, but which way are they supposed to be turned? I didn't install it yet because I wanted to pick up and install a clamp for my new fuel line before I put it back.

Also, side question - my breather hose was so hardened at the breather end (age and heat, I imagine) that about 1/4" of it broke off and stayed on the breather. I think there's still enough to reinstall the original hose, but what material is it? Any tips on a source for a new one?

 

[Roostabunny]

Before Pics

Before Pics

OK, here's some before pics - the boots were obviously a mess. That #1 in particular was so shrunken it didn't even like to stay seated.

 

[Roostabunny]

Before pics

Before pics

OK this is a pain posting one pic at a time - and I don't have a photobucket account yet, so I'm posting a link to my Google web album for the rest if you're interested...

http://picasaweb.google.com/roostabunny/GS850AirboxFixup

 

[bwringer]

Are you referring to the airbox boots or the cylinder head boots?

If you're talking about the airbox boots, there should be a mark or notch that needs to face up. If they're marked "R" or "L", the letter will be on top. However, I don't exactly remember how these work, to be honest.

I think you've seen this, but in case you're asking about the cylinder head boots:

 

[Roostabunny]

Are you referring to the airbox boots or the cylinder head boots?

If you're talking about the airbox boots, there should be a mark or notch that needs to face up. If they're marked "R" or "L", the letter will be on top. However, I don't exactly remember how these work, to be honest.

Definitely airbox. Sounds fine - I'll try to fit it to the carbs with letters up. Can't be harder than it was with the old hard boots.

Cheers

 

[49er]

Check that breather

Check that breather

while you have the end caps off your airbox. Just below the breather inlet(internally), there is a tract that spans most of the top of the airbox. It is relatively wide but very shallow, maybe 2-3mm deep. Due to years of condensation being trapped in this area, it rusts and eventually closes over causing the crankcase to pressurize, forcing oil out of any ageing seals around the top of the engine. Make sure that this tract is thoroughly cleaned out while you are doing your sealing repairs. I used a piece of 1.6mm Tig welding wire to clean mine out.

The breather hose is usually rubber. By the sounds of it, your old one was plastic.

 

[Roostabunny]

while you have the end caps off your airbox. Just below the breather inlet(internally), there is a tract that spans most of the top of the airbox. It is relatively wide but very shallow, maybe 2-3mm deep. Due to years of condensation being trapped in this area, it rusts and eventually closes over causing the crankcase to pressurize, forcing oil out of any ageing seals around the top of the engine. Make sure that this tract is thoroughly cleaned out while you are doing your sealing repairs. I used a piece of 1.6mm Tig welding wire to clean mine out.

The breather hose is usually rubber. By the sounds of it, your old one was plastic.

Good tip on the breather "crawlspace" thing, thanks! You can see rust residue in the breather pipe flange thing in the pictures - and now I know where that's probably coming from!

Yeah the hose is rubber, but it feels like plastic at the engine end, probably due to heat and age. I'll just measure the ID I need off the flange and find some rubber hose. I thought about fuel line - but that's fancier than I need, I'm sure.

 

[catbed]

you want to install the boots with the letters on the top side, towards the seat. make sure they have the metal rings in them.

 

[Roostabunny]

you want to install the boots with the letters on the top side, towards the seat. make sure they have the metal rings in them.

I don't think the '81 had the metal rings. They're not in the fiche, and I'm sure I didn't have any when I took mine apart. They are in the fiche for the '83 (edit - oops, thought yours was an '82 for a sec), however.

Either way - letters-up seems to be the consensus. Thanks!

 

[catbed]

for some reason, i thought yours said 1983. i was probably asleep still. sorry

 

[Roostabunny]

while you have the end caps off your airbox. Just below the breather inlet(internally), there is a tract that spans most of the top of the airbox. It is relatively wide but very shallow, maybe 2-3mm deep. Due to years of condensation being trapped in this area, it rusts and eventually closes over causing the crankcase to pressurize, forcing oil out of any ageing seals around the top of the engine. Make sure that this tract is thoroughly cleaned out while you are doing your sealing repairs. I used a piece of 1.6mm Tig welding wire to clean mine out.

The breather hose is usually rubber. By the sounds of it, your old one was plastic.

BTW, I don't have any TIG wire around, but 2mm wire cut from a coat hanger should do the trick, too, right?

 

[Roostabunny]

for some reason, i thought yours said 1983. i was probably asleep still. sorry

No worries, I called yours an '82 then edited after the fact. :-D

 

[Big T]

OK, here's some before pics - the boots were obviously a mess. That #1 in particular was so shrunken it didn't even like to stay seated.

You may find it easier just to replace the boots at the airbox. It's not very spendy and it makes carb installation waaaay easier. Also, the carbs respond better to a properly sealed system.

As for the hose, the correct size material should be available at the car parts store. Just take the airbox in and test fit. A little snug is better than loose. It's only a few $$, so get it plenty long.

 

[Roostabunny]

This is basically a partial re-post from another thread - but it seemed relevant here too...

Thanks go to 49er for the tip about the breather galley thing. I didn?t even see that when I was cleaning originally, and when I ran the coat hanger wire through there I ended up with about two tablespoons worth of rusty gunk. Yikes! I sprayed a little PB Blaster up there after cleaning, hoping to slow the return of more rust. Based on the volume of crud it?s likely that the breather was restricted, and I?m hoping my oil seals will get a nice break.

I struggled with getting the airbox back on, but only for about 3 minutes. After all I?d read about the magic moment of reassembling the airbox to the carb with new boots, I knew something had to be wrong. I?d installed left and right boots ?Letter Up?, but trying to get them hooked up made me think maybe that was backwards, since two boots on one side went fine and the other two were visibly not aligned. Upon closer inspection, I noticed that there was a Braille-like raised dot on the flange of each boot. Then I noticed four identical raised dots on the airbox ? one under each hole. Those clever engineers! I spun the boots ?Letters down? to align the dots, tried again on the carbs, and got to experience my own ?magic moment? when they popped right on.



Anyway, not sure if the braille dots are unique to the '81, but the correct orientation sure seemed obvious once I noticed them. Thanks again for the help, fellas!

 

[49er]

This is basically a partial re-post from another thread - but it seemed relevant here too...


I struggled with getting the airbox back on, but only for about 3 minutes. After all I?d read about the magic moment of reassembling the airbox to the carb with new boots, I knew something had to be wrong. I?d installed left and right boots ?Letter Up?, but trying to get them hooked up made me think maybe that was backwards, since two boots on one side went fine and the other two were visibly not aligned. Upon closer inspection, I noticed that there was a Braille-like raised dot on the flange of each boot. Then I noticed four identical raised dots on the airbox ? one under each hole. Those clever engineers! I spun the boots ?Letters down? to align the dots, tried again on the carbs, and got to experience my own ?magic moment? when they popped right on.



Anyway, not sure if the braille dots are unique to the '81, but the correct orientation sure seemed obvious once I noticed them. Thanks again for the help, fellas!

Good to hear that you are almost ready to go!
Thanks for sharing the info on the boot to airbox orientation. I have never notice this on my system. My engine runs VM carbs so the airbox markings may or may not be there! I haven't experienced any diffficulties when fitting up my airbox to the carbs, but it sounds as though many others do.
I think that you may have identified the root cause of much of the frustration/difficulties that others have reported. Well done.