Mikuni Carb JIS Screw sources

[srsupertrap]

I am refurbishing a set of Mikuni Flatslides which are no longer supported by Mikuni, Sudco etc. I found one of the throttle shaft screws had been replaced with a non-OEM M4 (black) screw shown below.

I would like to find a OEM zinc plated M4 with the unthreaded shoulder. I reviewed the current Mikuni RS 34-36-38-40 series exploded view but the parts list does not include the metric thread size.

Recommendations for a good source of JIS hardware?

JIS Screws.jpg

[Nessism]

https://www.littlehousesupply.com/Home.aspx

These are okay. The head shape isn't perfect, but they are reasonable. They don't have a unthreaded section, though. Why do you need that?

[srsupertrap]

Ed, Looks to be functional since the unthreaded shoulder section of the screw makes a tight tolerance fit with the TV.

Thanks for the link!


TV Screw.jpg

[srsupertrap]

This M4x13 throttle shaft screw with an unthreaded shoulder does not look to be available.

I checked Sudco & Jets R-Us VM33 & V29 Smoothbore exploded views. Thought it might have been a Mikuni P/N VM33/73 or N138.186 but Sudco does not include it in their 2023 price list. Jet-R-Us states its N/A too. I checked McMaster-carr, Ebay, NBK1560, Misumi, Little House Supply, Belmetric all with no luck. The JIS M4 screws for sale are fully threaded and even size (10, 12, 16mm) lengths too.

Any have other JIS hardware suppliers I should check? If this screw looks familiar, used works too!

[Nessism]

What about VM slide screws?

[srsupertrap]

Good idea! VM 26/28s use 5 M5 throttle shaft screws (bolts).

PS: I see Dorman sells packs of M4 x 25 bolts which are unthreaded 1/2 down the bolt. Perhaps I can rethread the section with a M4 die and cut the bolt to length?