Not sure why my carb slide is so scored up like it is. The air cleaner seems good and I saw no signs of dirt around the intake side of the carb. Does this slide need to be replaced? I am trying to sort out a poor running idle to 1/8 throttle range. 
imgur.com/a/tcsE2Qi

Blimey never seen damage like that before unless man made damage. I don't think it would affect carburation though. Hows the carb body where it runs.

I just disassembled the carb and put it thru the ultrasonic cleaner for a few rounds and the bore looks fine. It’s already assembled and back on the bike or I would try and take photos. The only slide I can find is on eBay for $50 and it is a Yamaha part. The seller has 5 of them. Slides for smaller carbs are selling for less, of course because I don’t need them!
imgur.com/a/rn0Dza3

Tall cap carb?  What diameter and cutaway is it?  Does the cable attach with screws and a bracket?  I might have one. 

Hmm, they look nice new don't they.
Was the running problem there after the ultra clean, or have you just done that now & not yet tried it.
If Mark doesn't find a slide it'd be interesting to see how it now goes after the clean.
Realy need to poke each jet to be sure to be sure especialy the pilot jet & the choke fixed jet in the bowl cavity.
Did the center emulsion tube [needle jet] come out for the cleaning.
Hope you end up with a new slide though.
If only it could talk & tell us how that happened.

Yes it is the tall cap carb.
It has a 3.0 cutaway.
No it does not connect with screws and bracket.

Motosport.com claims to sell them for $34.25 but I have never bought from them....

I did not ride it after the cleaning but will report back this evening after I test ride it.
I poked thru all jets including the fixed orifice choke jet.
Yes the emulation tube came out for cleaning.
the slide needle seems to show some wear compared to my others, but i wouldn't think that would effect the idle to 1/8 throttle range.

If the slide needle is showing wear then it's likely the metering part of the e/tube is worn too & can get bad enough to be able to view it egg shaped to the naked eye. So yes it could affect 1/8 throttle & even affect idle mixture. There needs to be a small gap under the slide to idle but that's enough for it to suck hard across there & it'll suck fuel out that nozzle if there's wear. To add, if wear is bad enough it will affect the carburation right through the range & dropping the needle just masks the issue at the rpm ya trying to smooth out & can just move the issue higher up. That's in a bad case of course.

If that slide wasn't always that way since you had the bike, check the air box! 

That era had an issue with the airbox seams letting unfiltered air into the engine. 

Not sure I replied to the right post now. Never mind. Oh yep slide needle wear you said. I'm on the right page.