Why are carbs 1&4 different from 2&3?

[Anonymous]

I'm curious about something -- not world-ending stuff, just stuff that made me go, "Hmm?" The bike is a 1982 GS1100GL.

The float bowls for the 1&4 carbs are different from the bowls on 2&3. The biggest difference is that the drain slots are 90 degrees rotated from each other. The outer carbs have drain slots that are fore and aft of the hole, and the inners have slots left and right of the hole. (I may have that backwards, but you get the idea.)

Also, the float bowls on the outer carbs are much shinier than the inners. This is confirmed by the photos on pp.132-134 of the Clymer's manual.

And there's one more, tiny, tiny difference. On the outer carbs, the drain slots go all the way through into the bowl. On the inners, the slots stop just short of the bowl, leaving a very thin little lip. I noticed the effect of this before I saw the cause. Ever notice that the inner carbs drain a *lot* more slowly than the outers?

So what gives? Suzuki wouldn't have made them different (therefore increasing inventory holding costs, the potential for misassembly, etc.) unless they had a reason. So what reason could there possibly be for rotating the drain slots by 90 degrees? For making them shinier? For making them drain more slowly?

I just don't get it. Any ideas?

D

[Anonymous]

different carbs

Are the drain holes different so they can be reached with a screwdriver while in place?
The shininess is costcutting. Only polish what peopek can see. I have some sixties motorcycles that have the exhaust pipe polished shiny except where the heat shield covers the pipe. In that area its just a little better than brushed finish.
The 1150 carbs are jetted differently, inside carbs slightly larger than the outside ones , but thats to compensate for cooling etc.

Suzookeeper Ger

[Anonymous]

Re: different carbs

Are the drain holes different so they can be reached with a screwdriver while in place?

The holes are all in the same place. The only difference is that the slots attached to the holes are rotated by 90 degrees between the outer and inner carbs. I can't imagine why this would make a difference to getting the screws out, which is a PITA in any case.

The shininess is costcutting. Only polish what peopek can see.

I could see that. I guess they saved more money by not polishing them than it cost to maintain inventory on two different parts.

The 1150 carbs are jetted differently, inside carbs slightly larger than the outside ones , but thats to compensate for cooling etc.

Is this true on any other models? Are all the jets on my 1100 the same?

D

[kz]

Re: different carbs

Is this true on any other models? Are all the jets on my 1100 the same?

D

The GS1150 is jetted different only on some markets (General markets, meaning country code 1, South Africa, Australia and Canada.

In Sweden for example, the jets for all four carbs are the same.