I think I found the hot ticket! Yamaha GT80 Carb

The 26incher · #1 01-22-2010, 01:29 PM

I have a feeling this will work. I have a trick 1973 Yamaha GT1/GT80 that I just scored a Webco head for and I think the carb will work perfect on a 2 stroke 66cc bicycle engine. Yamaha made the GT80 for close/over 10 years so I know you can get jets from Yamaha. Take a look at the pic's. The intake flange is just a little bigger but I'm sure you can shim it up. The over all size of the carb is not much bigger but as you can see in the pic's the slide is much larger. You have a air/fuel screw, slow and high speed jets! What more can you ask for? I'm going to try this out here soon on my bike and play around with jets. I will let you know how it works out. If anyone else has used a Yamaha GT80 carb, please let me know what size jets you are using if you are @ sea-level. I'm sure you can pick these carbs up on E-bay cheap. 5000

**Dave31** · #2 01-22-2010, 02:06 PM

I have the very same carb but have yet to use it. I have no ideal what I am waiting for.

marts1 · #3 01-22-2010, 03:58 PM

For someone else to say it works.

**Dave31** · #4 01-22-2010, 04:09 PM

Quote:

Originally Posted by marts1

For someone else to say it works.

Someone on the forum has used it but that was so long ago I cant find the thread or remember who it was

Venice Motor Bikes · #5 01-22-2010, 04:32 PM

You should try to make a larger ID intake manifold to go with it!

longhair · #6 01-22-2010, 06:15 PM

Quote:

Originally Posted by The 26incher

I have a feeling this will work. I have a trick 1973 Yamaha GT1/GT80 that I just scored a Webco head for and I think the carb will work perfect on a 2 stroke 66cc bicycle engine. Yamaha made the GT80 for close/over 10 years so I know you can get jets from Yamaha. Take a look at the pic's. The intake flange is just a little bigger but I'm sure you can shim it up. The over all size of the carb is not much bigger but as you can see in the pic's the slide is much larger. You have a air/fuel screw, slow and high speed jets! What more can you ask for? I'm going to try this out here soon on my bike and play around with jets. I will let you know how it works out. If anyone else has used a Yamaha GT80 carb, please let me know what size jets you are using if you are @ sea-level. I'm sure you can pick these carbs up on E-bay cheap. 5000

Nice Pix 26! There's no reason it should'nt work once you get the air/fuel mixture dialed in correct. keep us posted for results, Thanks

Nougat · #7 01-22-2010, 08:19 PM

I have a 1972 Yamaha U7E, uses the same engine as the PW80, and probably that GT80, too. That carb is a Mikuni, and the CNS carb that's being sold as a performance upgrade for the HT motors is a knockoff of that carb.

The float bowl on mine was shattered into a million pieces and epoxyed back together, so I bought this knockoff carb for replacement parts:

New-Yamaha PW80 PW 80 Carburetor/Carb Dirtbike 83-06 : eBay Motors (item 280443664473 end time Jan-04-10 12:06:12 PST)

In short, I haven't done it myself, but if the CNS carb will work, so will this one.

Edit: I should note that not all the bits in the knockoff carb I bought are exact fit replacements in the old carb body. The carb top is different, the needle valve is a little different. The emulsion tube and main jet are same enough, but the pilot jet is a little different. Float is the same, and thankfully, the float bowl is the same. The quality of the jets is not as good as the Mikuni brand stuff, so I cleaned the heck out of what I had and reused them.

skipu · #8 01-26-2010, 10:24 AM

Quote:

Originally Posted by marts1

For someone else to say it works.

ha ha ha ha hee heee heee heeee ha ha

GreenPurgatory · #9 02-04-2010, 10:07 AM

I definitely want to change the carb, but I am undecided as to which route to go.

What would be necessary to make the PW80 carb to work?
New-Yamaha PW80 PW 80 Carburetor/Carb Dirtbike 83-06 : eBay Motors (item 390142996674 end time Feb-12-10 20:00:00 PST)

Nougat · #10 02-04-2010, 10:26 AM

For these, you'd need a remote choke lever and cable, because this has an actual choke circuit. You'll need a vacuum tube cap, because there's a vacuum pipe on the carb that I believe is intended to run a diaphragm fuel petcock. That needs to be capped off. You'll probably need to play with jetting. And you'll need a lightweight air cleaner (see Venice's problems with broken intakes).