The Scorpa 125F has a very hard to get at fuel screw. Guess what, I never adjusted it. I have been looking for a long time for a fuel screw that you can adjust without tools. Jitsi has a screw for Mikuni carbs but I think it is an air screw only for twostroke carbs. In an ad for fiddy parts I saw this fuel screw for Mikuni 22 mm fourstroke carbs:

http://www.workzparts.com/default.asp?c=se...&query=1695

Do you think it fits the Scorpa 125F Mikuni 20 mm carb?

The Scorpa 125F has a very hard to get at fuel screw. Guess what, I never adjusted it. I have been looking for a long time for a fuel screw that you can adjust without tools. Jitsi has a screw for Mikuni carbs but I think it is an air screw only for twostroke carbs. In an ad for fiddy parts I saw this fuel screw for Mikuni 22 mm fourstroke carbs:

http://www.workzparts.com/default.asp?c=se...&query=1695

Do you think it fits the Scorpa 125F Mikuni 20 mm carb?

Difficult to know for sure. Sending the Swedish description through a translator doesn't produce very good results. But, from what can be made out, it appears that they are representing it as a pretty generic part, for any 06 or 07 Mikuni carbs, with a fine thread. Their only warning about possible problems appears to be in the last paragraph, where they point out that certain carbs, such as the VM26, may have a course thread, and not be compatable. One would assume that the VM22 would be a match, for the part.

I bought such a CMX fuel screw. It was cheaper from Staggs, SGR-USA.

The thread was right M6x0.5, the tip a bit different.

But the head didn't fit beside the float bowl so I turned it down a bit on a lathe.

After some more processing for grip and turn marks and mounting.

Screwing it in to the bottom produced the highest idle rpm so the tip was too different.

Edited June 24, 200818 yr by DennisGr

Old thread here but I just took possession of a TYS 125F and in messing with the carb I found I could easily adjust the fuel screw with the can opener of my Swiss Army knife. It's a Wenger model and the the can opener resembles a sharp hooked claw. I reach up and stick the sharp end in the slot on the screw and it turns about a half turn each time. I suspect a sharpened dental pick would work too but I would want to ride around with one of those in my pocket.

And I have the screw about 3 turns out.

Use a small blade bit from a screwdriver that has interchagable bits. If it's stiff, add a small socket for extra grip. (I think they're imperial - I forget the size)

Meanwhile, two years later...

 

The screwdriver can opener was getting old so I googled "TTR 125 fuel screw" and found this link.

 

Bought one (14 USD shipping! 48 usd internationall!!) and it seems to be working pretty well. I can reach it and turn it with my fingers. 

 

  

Edited April 15, 201610 yr by guido

Here's a couple of pictures of the Factory Pro fuel screw.

 

Compared to the OEM:

 

 

And installed on the carb (Mikuni VM20):

 

Edited April 16, 201610 yr by guido

Why dont you just clean up the original one and just solder (or even silver solder if you want even stronger) a little extension on end??

Thanks for posting.