Anyone know the allen key size for this highway peg?

[..]

The big one in the 90 degree join.

[WintrSol]

It looks the same as mine, which is 3/8"

[..]

It looks the same as mine, which is 3/8"

Not metric?

The smaller ones are 4.5 mm.

[Valker]

It looks the same as mine, which is 3/8"

Not metric?

The smaller ones are 4.5 mm.

The Honda stuff is metric, but many, if not most, accessories are SAE.

[Jess from VA]

That is Kuryakyn hardware, and they are (mostly) all SAE.

I just happened to need to snug up my Kuryakyn Hwy peg earlier today (not the same as yours).  Mine mount on the crash bars, and too snug is too tight to pull up from the seat (underway), and too loose and it falls down by itself.

I don't know the size, but it's the second biggest one in my 3/8 drive SAE socket allen set.

Probably 3/8.

Also, remember you can twist that Dually peg up a bit too. 

[WintrSol]

Nearest metric size would be 9.5mm; I don't have one that size.

BTW, 4.5mm is just less than 3/16"; does it fit a little loose?

[-mike-]

Do yourself a favor and get a proper SAE allen key set.
Just a little loose metric is just too loose. You'll screw up the screw. (Pun intended)

-mike-

[h13man]

Kuryakyn footwear has been SAE in all my experience. Purchase a set of quality hex key wrenches. You can buy both Metric/SAE twin packs for reasonable $$. Eklind or Baldor are excellent choices.

https://www.amazon.com/Eklind-Ball-Hex-wrench-Combo-22-piece/dp/B000189RGO/ref=asc_df_B000189RGO/?tag=&linkCode=df0&hvadid=310828259700&hvpos=&hvnetw=g&hvrand=17978653844076448267&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9016735&hvtargid=pla-441869621721&ref=&adgrpid=65583250281&th=1

[..]

The consensus being 3/8 inch I bought this set which will arrive Tuesday.

https://www.amazon.com/gp/product/B084V7KS25/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

It can go into my right saddlebag along with the other tools and stuff I carry.

My saddlebag metric set can stay in the garage along with my other metrics 

[..]

Nearest metric size would be 9.5mm; I don't have one that size.

BTW, 4.5mm is just less than 3/16"; does it fit a little loose?

Spins like a top.

[..]

Whilst I have your attention what size Allen bolt do I need for the brake/clutch fluid covers?

[Jess from VA]

Using the parts fish, see #21  (clutch, but both use the same screws (not bolts).

Says "SCREW, FLAT (4X12) "  Stock is Phillips/JIS heads.  You get one in a hex flathead, but no idea what the hex size will be. 

https://www.procaliber.com/oem-parts?aribrand=HOM&arian=MOTORCYCLE#/Honda_Powersports/GL1500CA_(99)_VALKYRIE%2c_USA%2c_VIN%23_1HFSC340-XA200001/CLUTCH_MASTER_CYLINDER/4a380688-44e5-4f7d-9a7d-1f19c6a1fb1b/52230c0a-4d31-4e0e-990d-fde2104bda7b/y

Take one of your screws to a good hardware store.

[..]

Take one of your screws to a good hardware store.

Yep , my local ACE will be getting a visit,

[..]

The consensus being 3/8 inch I bought this set which will arrive Tuesday.

https://www.amazon.com/gp/product/B084V7KS25/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

It can go into my right saddlebag along with the other tools and stuff I carry.

My saddlebag metric set can stay in the garage along with my other metrics 

Well made allen keys and a sturdy plastic box to hold them.