Topic: Does E10 gas eat viton on float valve needles?

[sir funk]

Found a source for rubber tipped needles with seats for 400F (and 500/550) here: http://www.smebike.com/index.php?route=product/product&product_id=2348  (of course they are out of stock)
Is anyone having trouble with these in ethanol gas? My cousin is a mechanic that almost exclusively works on carbureted cars and he's been telling me that hes been swapping out many viton tipped float needles for plain brass because the ethanol softens them up and destroys them. 

Looking into the different grades of viton rubber, it looks like there is a type that stands up to ethanol, but not sure how commonly this is being used. 

Anyone having issues with viton tipped float valve needles?

edit

Also any alternate source for rubber tipped needles for the 400 four?

[sir funk]

I did a bit more research and all modern float needles should be made from Viton F , which is impervious to methanol and ethanol. So should be OK for those needles mentioned above. 

I believe the issues my cousin was having was from carbs that had float needles manufactured prior to when viton F was the standard for parts exposed to fuel.

Hopefully they will get some more in stock sometime soon. Haven't yet found another source.