Hi, just wondering if anyone has their GS slightly disassembled that might be able to take a couple measurements for me...

I need to know the diameter (ID and OD) of the carburetor outlets and the diameter (ID at least) of the engine intake manifolds. I'm doing a little project and those measurements would really help, but I'm hesitant to take apart my GS if someone else on this forum could help me out! If my project is successful, I'll have some really good news for people who want to get significantly better gas mileage out of their GSs.

Thanks in advance!


... Dang, some of these verification questions are sending me to Google...

I can take some measurements later this week, but I can tell you GS500 carbs fit in GS450 engines. The intake boots match up with no problems, etc, etc..

What are you up to man? Fuel injection?

Im probably working on my carbs somewhere next week. So if i don't forget it, and big rich hasnt gotten back to you yet, i might be able to help.

Oh and sign me up to your fuelsaving thing! i love experimental stuff!
Maybe it isnt necesary for you project, but how do you expect to do a project on fuel efficiency, if you are hesitant to take off your carbs?

The 3 circuit carbs have a 1 mm larger diameter body and a slightly larger manifold boot but some here have reported fitting the larger carb into the tighter boot, it might depend on how old the rubber is?  I have no experience with trying it myself.  89-00 models had 2 circuit carbs and 04-09 had 3 circuit carbs.

On the engine side, the early carbs (2 circuit carbs Jack mentioned) have an OD of 42mm and an ID of 33mm. The airbox side is more complicated since it has an oval shape intake and bell-shaped throat. I can take measurements w/ pictures later, but not sure what you're looking for....

Awesome! Thank you so much, Big Rich! That's exactly the info I needed.

I'll tell you about what I'm working on. So what does a carburetor do? It takes liquid gasoline and mixes it with air for delivery to the engine, right? Well, carburetors are notoriously inefficient and produce what is, at best, a gasoline mist. Liquid gasoline doesn't combust like gasoline vapor, so all those extra droplets of liquid gas just get wasted with each power stroke of the cylinder. So what would be better? Gasoline vapor, all gas, no droplets.

I'm designing a gasoline vapor "carburetor" specifically for the GS500. I've seen very simple versions easily set up for lawnmowers that work quite well. I've seen promising versions set up in cars, but not entirely successfully. My design, if all goes as planned, will be able to be installed in under an hour and will occupy the space currently taken by the GS500 carbs and airbox, and will replace their functionalities much more efficiently. It would also be 100% reversible in the same amount of time.

Once I've finished the prototype, I'm going to make a video where I fill the tank, ride about 100 miles, and then fill the tank again for an approximate gas mileage (yes, it will be a long video, but making any edits would make my results appear dubious). I'm hoping for at least 80-100 mpg. Further development could boost that number, but would require a lot more modification, as the next step would be to utilize exhaust to heat the incoming fuel vapor.

There are a lot of nay-sayers to this kind of project, but being I've personally witnessed the success of this setup in simpler applications, I believe I can get this working. If I succeed, I'm going to offer to produce kits to members of this forum and then develop a kit for my Honda Shadow 750.

So, thanks to Big Rich for saving me some time, I'm off to order some parts!

That is quite the claim! It sounds amazing.

I'm skeptical, but, I'd be willing to try this out, certainly.

Keep us updated.

Likewise interested;

some light reading; http://autoresource.internetautoguide.com/myth-100-mpg-carburetor-1133.html