What carb to buy??

[stalker stopper]

Hey All

I am wanting to buy a new carb for my 85 TRI-Z. I like to do a little bit of desert trail and Pismo/glamis type riding. Ebay has the Keihin PWK 38 air striker or the Keihin PWK 39 What should I spend the money on?

Thanks

[Toledo_Tommy]

What type of motor work has your bike have done ? I Just picked up a 36mm keihin carb for mine , You will need a different throttle cable tho.