Do Aluminum Fuel Mixture screws always come loose?

Bought a Tusk Aluminum Fuel Mixture screw so that I can lean out my WR426 when I climb from 4500 ft. (home) to around 9000 ft. here in Utah where it gets hard to restart (even with the hotstart) because it is too rich.

A friend told me tonight that all fuel screws that are aluminum and not brass are known to always come loose and fall out of the carb. Is this true? He told me not to install it because it happend on his KTM 450EXC. Should I try to find a brass fuel mixture screw? Anyone heard of this?

Tusk Aluminum Fuel Mixture screw


theres an oring that puts some friction on it to prevent it from backing out. i havnt had a problem with mine yet (zip-ty). why would brass be any different?

it makes it sooo much easier. i'd highly recommend it.

keep an eye on it if your worried

If stalled properly you should have no worries :thumbsup:

Just make sure the o-ring and spring are in correct and you'll have no worries.

I lost mine but it was because i had it turned out 3 turns and was told any past 2.5 would make the spring weak and cause it to fall out. i since bought a new one with a stiffer spring to help prevent this, and duct taped it in place after finding the sweet spot about 2 3/4 turns for me.....

I safety wired mine.

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