1981 GS450S Carb rebuild

[Anonymous]

I have a couple questions I was hoping someone out there could help me out with. I am trying to rebuild a spare set of carbs for my 81 GS450s. I have looked at the carb rebuild guide on this site, but my carbs appear to be a bit different than the ones used in that guide.

The carbs I have do not appear to have a removable or adjustable air screw.(pg.17) Can anyone confirm this?

I also can not locate a removable air jet (also pg.17)?

I think I have the carbs completely dis-assembled and ready to soak in carb cleaner, but I want to make sure that I have not missed any o-rings or non metal parts. The carbs in the guide seem to have a lot of o-rings due to the fuel tubes and vent tube, but this 450's carbs doesn't have fuel tubes and the T doesn't have o-rings. The only o-rings I have found are on the needle jet and the drain plug. Does anyone know any that I have missed?

It seems the carb is ready to dip...I hope so.

Any help is appreciated.

Cheers!

[Anonymous]

There are air screws on these. I have a set of carbs from a 1980 GS450, and as well from a 1983. The 1980 are different as you stated. There are air screws however. Perhaps the caps have not been drilled out on yours yet. You better check into that before putting these in the carb cleaner.

You are right in that there are fewer o-rings on these.. but there are also o-rings on the air screws.

[Anonymous]

That is what I thought. I have read a few threads while searching that briefly mention things like drilling out caps to gain access to the air screws, but nothing clear. The air screws are definetly not located in the same place as it is shown in the guide.

Can anyonme offer anymore info on the airscrews?

[bgmart450]

The schematics from the microfishce I have for a 1980 450 (same carbs) show 2 O-Rings, one on each of the needle jets and one on the drain bolt on the bowls (but mine has a washer there?!?!). I may be missing something about other plastic/rubber bits tho.

Try here: Bike Bandit - 81 GS450 carb schematic
and check for all the little rubber bits.

Depending on how long it will take to get my needle jet o-ring I may dip mine as well. I'd like to know where all the little rubber parts are too.

[Anonymous]

That's the same schematic that is in the Clymer manual and my drain bolt also has what appears to be a washer or maybe it's just an old flat o-ring?

[Anonymous]

Well I just received my o-ring kit from www.cycleorings.com. Unfortunetly none of these o-rings seem to be the right size for my needle jet.

Does anyone have a source for the needle jet o-ring for 81' GS450S?

[bgmart450]

I just got 2 from a Suzuki dealer here in town. If you wanna call one near you you can ask for Suzuki part number: 13295-31210. I called today and they had them in stock. $1.15 a pop.

[Anonymous]

Ok, found o-rings for the needle jet at a dealer. Had to call 5 dealers nearby and finally found one that had them in stock.

Anyone wanna comment on the air screw issue?

[Anonymous]

Man the search function of this site is lacking. I've been trying to search a bit more to find out about the air screws. I'm not having any luck. Searching for '450 air screw' doesn't even return this thread?!?

Please if anybody has any more info on a having to drill out some sort of plug to get to an air screw, post it. I really don't want to dip these carbs and ruin any o-rings on airscrews I can't even see.

Thanks!

[Anonymous]

That is what I thought. I have read a few threads while searching that briefly mention things like drilling out caps to gain access to the air screws, but nothing clear. The air screws are definetly not located in the same place as it is shown in the guide.

Can anyonme offer anymore info on the airscrews?

On the 1980 carbs (I assume they are the same for '81) the air screws run horizontal across the top of the carb ends that go into the manifolds.
The screw heads face outside, and that is probably where the caps are that you would need to drill out.

[Anonymous]

Take a look at the pic below, is the yellow arrow pointing to the spot I am supposed to drill out to get to the air screw?

[nabrams]

Yes, that's it. I had to do the same thing on my 1980 GS450 (I believe 80-83 all had the same carb).
A word of caution: Drill very carefully and slowly so that you dont ruin the adjuster beneath the cap you're drilling out!

[Anonymous]

Thank you! I have air screws!!

For those who are going to drill out the plugs...be very carefull the plugs are only about 1/4 inch deep and the screws are right below them. There is not much room to drill through. I started with a very small bit and worked my way up to something almost the size of the plug. Once I drilled through, I was able to use a small screwdriver and gently pry the remaining bits of plug out.