Idle Screw and Mikuni VM26 Clone on TT250
 

I bought one of the red screws and it fit fine on my Mikuni vm26 clone. The needle taper looks a bit different but it seems to work ok. I still have some work to do dialing in the Mikuni, but accel and off idle are now working fine - I just have a pretty bad backfire on closed throttle higher rpms. Here is what I have done to date:

• Aftermarket exhaust "like everybody else has"
• Airbox delete, trash can mod and pod air filter
• Mikuni VM26 clone carb
• Extended idle fuel mix screw
• Jetting is (I think) 120 main / 25 pilot
• Needle in 4th slot (1 rich from center)

I am pretty close on the carburetion but need to dial in the pilot mixture a bit more. The extended screw fitted fine, but forget requesting a color, I asked for black or silver and got red, LOL.

Before I dropped the needle clip to richen it up I had a bad hesitation just off idle, and richening up the pilot jet did not help. Dropping the needle clip to raise the needle and richen initial slide opening seems to have cured that issue. I am going to start a new thread with my results as soon as I get this dialed in.

Dave, do have a link for the one you bought? Some of the ones I'm seeing on Amazon say they are for Keihin. I know that ours are Mikuni based but they all the same on the site.

I just bought a billet one off eBay for under $6.00. It’s the only one on there that says it’s for the pz30 (and I believe vm26).

I’m tired as hell of trying to reach that screw. I’m happy to let you all know how it fits and works once I get it delivered.

Not 100% sure if this is the same one that 02jmpr bought but here is my link:
https://www.ebay.com/itm/Mikuni-VM26...53.m2749.l2649

Billet Air Fuel Mixture Screw Adjuster For MIKUNI VM26 PZ30 30mm Red Carburetor


Search for that. Sorry no direct link. I bought that one because it specifically said Pz30. As soon as I get a t I’ll let you guys know if it works. Promise. :)

OOPS - I THOUGHT this thing screwed in okay, but today when I was changing pilot jets it was apparent that the threads and shaft are either slightly too small (Maybe 0.5mm?) or this thing is just not the right pitch. Either way the durn thing won't screw all the way in now and pulls out, so I put the stock mixture screw back in. I still haven't figured out how to adjust it without burning my fingers though!

The painfully tedious way I've been adjusting up to now is to cut a small length of hose and jam a screwdriver bit in the end. I hold it between my two index fingers and rotate back and forth like I'm trying to start a fire with a stick. If I try to use one hand to get a grip on it something gets burnt for sure. Using two hands I can get my hands into a tight enough wedge to afford a little breathing room. That said, I usually drop it 5 times to every time I get it in there and I only get a half turn max before I have to reposition.

I do have a 90 degree bit driver from Harbor Freight but it's too short to use the handle and there's not enough room to spin the end by hand. I think Megadan has gotten that method to work for him though.

This fuel mixture screw came in a pz30 carb kit I bought on ebay. Makes adjustment a bit easier.

This one https://www.ebay.com/itm/282484440706 does NOT fit. It's not even close. The needle is too short, wrong taper and the threads are completely different.

I quit. It's easier to just suffer the burns and hand cramps at this point. :)

I just tried to contact the seller before leaving NFB on Ebay and funny enough, the seller is no longer listed as an Ebay member. Seems like Ebay used to be great a decade or more ago but it's so full of scammers and crap now I don't want to use it. Don't get me wrong, I love my Hawk but finding parts that aren't at CSC is a real bugger.