Autoshoer said:
Has anybody tried to simply use some silicone sealant instead of the intake orings?
We're talking about CARBURETOR o-rings here. Little bitty ones...
But anyway: NO! Silicone will NOT work to seal the intake boots. Silicone does not stand up to gasoline.
In fact, DO NOT use silicone sealer ANYWHERE on your bike, except as a very light, transparent film when absolutely needed to make an old bunged up case cover oiltight. Silicone just loves to get loose and plug oil passages.
Anyway, here's what I've found regarding these intake o-rings:
(the whole article is here:
http://www.bwringer.com/gs/intakeorings.html )
Robert Barr's intake o-ring page is here (no, he does not sell intake boot o-rings):
http://cycleorings.com/intake.html
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On a GS 850, the o-rings are Suzuki part number 09280-38004. You can order them from any Suzuki dealer or from Ron Ayers or Bike Bandit. If you're ordering more parts at the same time, Ron Ayers is a bit cheaper than Bike Bandit, but you'll need to provide the above part number. In any case, the four o-rings should total less than $5, which is probably less than the shipping costs.
In order to withstand the extreme heat of the cylinder head, these o-rings are made of a special material called Viton. Don't substitute o-rings from the hardware store or from an assortment!
You can order Viton o-rings that will fit from McMaster-Carr in standard size 128. They come in packs of 25 for about $11.00, so there's really not much savings unless you're doing more than one bike, or you just like having a lifetime supply on hand. These o-rings are also a bit fatter than the Suzuki o-rings, which might be good or bad.
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FWIW, I installed a set of the Viton o-rings from McMaster-Carr last year just to see what would happen. The bike ran fine all summer, and when I pulled them out this spring, they were in excellent condition -- still pliable and not swollen.
However, the 128 size o-rings are a tiny bit fatter than the OEM o-rings. They pretty much fill the groove in the intake boot completely, and when you tighten the bolts, the o-ring gets squished with nowhere to go. This leads to tiny shreds of the o-ring getting extruded into whatever space they can find between the head and the intake boot. In this case, this is probably not really harmful and the seal is just as good. Maybe. Possibly. I think. Don't try this at home.
It was just an experiment, and I replaced the substitute o-rings with the correct OEM o-rings this spring.
Bottom line, just order the OEM o-rings. They're cheap, they fit perfectly, and it's a lot easier to find Suzuki parts than Viton o-rings.
Here are the bikes that this part number fits, according to the Mysterious Oracle of Parts (
http://www.cpixel.com/bikeparts/part_search.asp ):
1980 GS550,E
1980 GS550L
1980 GS850G
1980 GS850GL
1981 GS550L
1981 GS550T
1981 GS650E
1981 GS650G
1981 GS650GL
1981 GS850G
1981 GS850GL
1982 GS550L
1982 GS550M
1982 GS650E
1982 GS650G
1982 GS650GL
1982 GS850G
1982 GS850GL
1983 GS650G
1983 GS650GL
1983 GS650M
1983 GS750E, ES,
1983 GS850G
1983 GS850GL
1983 XN85 D
1985 GS700E, ES
Now, back to the discussion of CARBURETOR o-rings.