Fuel Screw Fix

I made/installed an "adjust on the fly" fuel screw handle shown on motoman393's web site today. Problem is, somehow the threads on my fuel screw got messed up and now it won't thread back in. Does anyone know of an easy way to fix the threads on these? I talked to a guy I know who runs a machine shop, and he said that it was imperial fine threads and good luck finding a die. A new screw is $30, but that may be my only option. Anyone have any ideas?

I don't know how bad your fuel screw threads are messed up. But if they are not to bad try using the corner of a small file to straighten the threads back up. This has worked for me many times.

If you lay the corner edge part of the file in the threads, you can recut bent or flattened threads. Just be careful not to damage the other threads while you are doing this. In your case I would recomend as small of a flat file as you can find. Hope this helps. :)

That Wylie guy knows his stuff. I've used the same technique before and it works great. Can you actually see where the threads are boogered? If the bad part is at the starting point, you can use the file to either bend or cut off the bad area so that you can get the screw started. Examine the threads with a magnifying glass and you should be able to see what needs to be filed. Be gentle with those brass threads.

Fix it if you can, but a new fuel screw with spring and washer from Sudco was cheap. I think mine was less than $10. There were three options, I didn't know the differences, but the 'standard' one worked fine. Just let the guy at the counter pick it. 3 days using priority mail for $3 shipping!

Good luck,


Mark, could you send me the website or give me a phone number? That beats the 30 bucks the dealer is asking by a longshot! Do all the dimensions seem to be the same? Regardless, I'll take one! Thanks for the info.


The are primarily a wholesaler, with retailers around the country reselling their products. For instance, if I call them, they will send me to Carb Parts Warehouse in Cleveland. But if CarbParts doesn't have it, I just say so to Sudco and I can order it there. I'll be no one else stocks the fuel screw. Again, and I don't remember the options, there are three fuel screws that are used in different FCR carbs. The one he picked worked fine.

Good luck,


Mark, do you have a part number? I went to the website and I couldn't find it. I need that part too! I need to make sure the beast is running good for memorial weekend. Please let me know. Thanks again.

[ May 14, 2002: Message edited by: cowboyona426 ]

Cowboya, There is such a file out there to repair damaged threads.- called a thread file. Possible could pick one up at local hdwr. store.

jdy- I'm aware of that, but the threads are so fine I don't know if it would work good or not. Also, I found a product called the Kouba T-Handle-I can get a trick looking T-handle adjuster with a fuel screw for 20 bucks! Thats cheaper than what Yamaha wants for just the screw, so I'm picking one up this week. If anyone else is interested in these, go to the website. There is a $25 minimum order, so order two and sell the other one to your buddy! I'm picking mine up in person, which is why I can buy just one. Anyways, its a great product, check it out at least!

Kouba Link

[ May 14, 2002: Message edited by: cowboyona426 ]

I made motoman's handle, but since buying the kouba handle with the screw is cheaper than a screw from Yamaha, I'm going that route. It's already assembled so I won't take a chance of boogering the threads again! I may try to Loctite it however. Thanks again for all the help!

Dont be lociting your fuel screw. Youll be sorry for sure!

Not the screw Shawn, the handle. I may be stupid about some stuff, but not that stupid :) !

Shawn, scratch loctiting the handle as well. The part I'm getting from Kouba is a one piece unit- fuel screw and handle all in one! :)


20 bucks for a kouba???? :) I made the one from motomans website and spent about 2 bucks. I took the savings and went and got beer. :D Seriously make motomans, I have had no problems with mine and saved a lot of money. I do see how those threads could get messed up though, they are thin. From what I understand you still have to press the kouba handle on so be really careful.

[ May 14, 2002: Message edited by: edareus ]

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now