Side branch from my resto-therad. Topic:carb float needles.

[puskrat]

Wildkat's (et al) excellent carb cleaning 101 has been invaluable to me in this process. Right now I'm stumped. Others have helped urge me along, but I'm kind of stuck. I've an 80 standard bike with 79 carbs. replaced float needles/seats with genuine parts from 'zilla. The hivemind here seems convinced viton tipped needles from the later carbs are superior to the original all steel pieces. I have some of both, had planned to use 79 steels, but got rubber tips on recommendation of others. my rubber tipped needles have the clips on the other end, which changes how they mate to the floats. I've even managed to break a clip off during experimentation.
1) is it possible to use viton tipped needles with 79 floats?
2) is it possible to use viton tipped needles with seats from the steel needles?
3) the float height measurement from the "gasket surface": is it from the surface OF the gasket, or the surface "for" the gasket (carb body)?

[MPittma100]

Wildkat's (et al) excellent carb cleaning 101 has been invaluable to me in this process. Right now I'm stumped. Others have helped urge me along, but I'm kind of stuck. I've an 80 standard bike with 79 carbs. replaced float needles/seats with genuine parts from 'zilla. The hivemind here seems convinced viton tipped needles from the later carbs are superior to the original all steel pieces. I have some of both, had planned to use 79 steels, but got rubber tips on recommendation of others. my rubber tipped needles have the clips on the other end, which changes how they mate to the floats. I've even managed to break a clip off during experimentation.
1) is it possible to use viton tipped needles with 79 floats?
Needle and seats do not care about which float they are attached to. Do use float valves (Mikuni only) for year of carb.

2) is it possible to use viton tipped needles with seats from the steel needles?
Don' mix needle and seats.


3) the float height measurement from the "gasket surface": is it from the surface OF the gasket, or the surface "for" the gasket (carb body)?

Measure from carb body gasket surface - no gasket.

[bikerphil]

I have always used the steel tip needles/seats in the 79 carbs the way it was intended. I know others have converted the early type carbs to the viton tip needles/seats, hopefully someone that has done that will chime in for you.

[TopCatGr58]

Hey Puskrat,

I haven't done the Viton for brass needle conversion on an early carb, but I have read about it on this forum. IIRC, you have to get some XV920 needle seats that will screw into the early model carbs, they are wider and accept the slightly larger Viton tipped needles. The vitons won't work in the OEM seat....they are too wide and will bind or such!

T.C.

[puskrat]

okay...I have three NOS 79 needle/seat assemblies, and I have replaced one needle with a later, viton tipped with clip at the other end, needle in a 79 seat. It's not happy, and the float height is definlitely not right. I thought it was moving freely, but it might be bound. Guess I'm going to go with the 79 seats and stick with the old all metal needles.....back to the shopping cart!

[dbeardslee]

I run XV920 fuel valves with viton tipped needles and plastic floats in my '79 carbs and they work great. I have manual petcocks on my tank, and I leave them on all the time and just let the fuel valves shut off the flow... and they do. Personally I think viton on metal provides a better seal than steel on brass.

[3Phase]

... Personally I think viton on metal provides a better seal than steel on brass.

And the ethanol in the new fuel doesn't etch Viton like it does brass. I have't heard of any flaming tragedies from that yet but it's something to keep in mind long-term. It's like the way termites can eat most of the wood before you notice it or the house falls over.