Carburetor differences! Understanding the changes...

[Shuriken]

My picture shows 2 carburetors side by side. The one on the left is from my 2002. The one on the right is from an unknown year.

Notice the R5 ID on the casting as well as the different internal tunnel length difference.

What was Yamaha doing here and is it ok to interchange?

 

[CaptainKyle]

I sent a message

 

[Graham]

The one on the left, is that a California model carb?

 

[Shuriken]

The one on the left, is that a California model carb?

I hope not!

As far as I know, my 02 is not the C model.

 

[Onetwomany]

For what’s it worth, I have a C model, and mine looks like the one on the left

 

[Shuriken]

For what’s it worth, I have a C model, and mine looks like the one on the left

Interesting. Thanks for posting. I have read that the C models had an extra port or something similar for extra emissions control. Someone can clarify. Can you take a pic of your carbs from the left leg side?

I think it is probably a design change based on year rather than C model though. I think the newer carbs probably got enhanced. Why else would Yamaha change their tooling?

I would like to specifically find out why the newer ones have that different casting tunnel.

I just mixed the one on the right in with 3 of the newer ones. I don't know how I would be able to determine its effect on performance though.

 

[apsolus]

Interesting. Thanks for posting. I have read that the C models had an extra port or something similar for extra emissions control. Someone can clarify. Can you take a pic of your carbs from the left leg side?

I think it is probably a design change based on year rather than C model though. I think the newer carbs probably got enhanced. Why else would Yamaha change their tooling?

I would like to specifically find out why the newer ones have that different casting tunnel.

I just mixed the one on the right in with 3 of the newer ones. I don't know how I would be able to determine its effect on performance though.

bro im a mechanic by trade, OEM's never need an excuse to retool! lol ive stopped trying to make sense of it all haha

 

[Maineiac70]

Look for different numbers stamped on the throttle plates. I had a mechanic strip out a mixture screw port on mine years ago, then did me a 'favor' by swapping the Internals to a spare carb he had laying around. Mine is a CA spec, he put in a 49-state one. Didn't run well at all, three mechs couldn't figure it out. I decided to pull and look at them myself, and noticed the different stamp on the plate, that correlated with the carb that was replaced.

 

[Onetwomany]

Interesting. Thanks for posting. I have read that the C models had an extra port or something similar for extra emissions control. Someone can clarify. Can you take a pic of your carbs from the left leg side?

I think it is probably a design change based on year rather than C model though. I think the newer carbs probably got enhanced. Why else would Yamaha change their tooling?

I would like to specifically find out why the newer ones have that different casting tunnel.

I just mixed the one on the right in with 3 of the newer ones. I don't know how I would be able to determine its effect on performance though.

 

[Shuriken]

Look for different numbers stamped on the throttle plates. I had a mechanic strip out a mixture screw port on mine years ago, then did me a 'favor' by swapping the Internals to a spare carb he had laying around. Mine is a CA spec, he put in a 49-state one. Didn't run well at all, three mechs couldn't figure it out. I decided to pull and look at them myself, and noticed the different stamp on the plate, that correlated with the carb that was replaced.

Welp...

This is the reason for this whole thread... the PO of the bike I recently acquired stripped one of the mix screws and the replacement carb is different.

The throttle plate openings on the ones I have are stamped the same, fortunately.

That cast tube passageway under the jet block on the newer one, the R5, and that the newer one seems to have some brass plugs vs tin or aluminum, is what I've noticed so far.

I'll see if I can find anything else.

 

[Shuriken]

Thanks for sending those pics. That bike is beautiful. Is that a C model?