Please refresh my recollection..

[Jess from VA]

of the diameter of the lower engine guards for highway peg mounts.

I cut the air scoops off my Interstate lower engine guards underneath to put a set of old Kuryakyn Ergo 4-screw heavy duty engine guard clamps there, and one of the old things stripped a screw.  Three is holding it pretty good, but I have my doubts on longevity.  I cannot find just the clamps for this setup anywhere (clamps to offsets to clevis to dually pegs).  Kuryakyn was bought out, and what remains is limited or unavailable. 

I just got down there and measured, and they look like one-inch (not 1 1/8"?).

It's probably been discussed here many times but my search turned up no answer.

[Chrisj CMA]

I always remembers the crash bars to use 1 1/8” clamps except the short bit underneath which is 1” However, that’s on a standard, the IS is different in many ways maybe IS crash bars are different.

[Jess from VA]

I always remembers the crash bars to use 1 1/8” clamps except the short bit underneath which is 1” However, that’s on a standard, the IS is different in many ways maybe IS crash bars are different.

Jeff, I think the only thing different between Interstate and Std/Tourer engine guards, is the (stupid) air scoops on the lower part of the front guards.

I think you're right that the round upper part of the guard is 1 1/8", and the lower support arm (where I want to mount my Hwy pegs) is 1".  

I have another set of Hwy pegs that were mounted to the round upper (main) part of the guard on my other bike, and they appear to have 1 1/8" Kuryakyn Quick Clamps.  So I don't think I can use those on the 1" lower part of the guard.  Those quick clamps are not as sturdy as the big 4 screw clamps, but I think I'm out of luck trying to find any more of those.  

I did go for a short 2hr ride this morning (before the rain), and the 3-screw clamp (one broken) held up fine.  It may continue to work that way, but it may shake loose, and I'm looking for 2 more clamps.  1" Quick Clamps may be my only option (except they may not mount up to my offsets, which I need for my short legs).  If you have to order the whole setup as a unit (clamp, offset, clevis, and peg) it gets expensive.
 
But thanks for confirming the 1 1/8" guards and 1" lower support arm, that's what I was trying to remember (or find out).  

[Cracker Jack]

Jess, you might be able to use the 1 1/8 clamps on the 1" part by using one or two (or more) pieces of leather for shims under the clamps. The boot scootin' boots you no longer use just might be the ticket!   Leather under the clamp might help keep the clamp from slipping.
I've used very thin (glove) leather in the past to provide added friction. Might also help protect the chrome! After install, just trim the leather flush next to the clamp to make it disappear.

[Jess from VA]

Thanks Jack, I've used rubber and leather (from gloves) to shim before.

With 3 of 4 screws holding that thing on there, I'm carrying a ratchet with proper hex drive so if it lets loose, I can pull the offset and peg off instead of it dangling down while riding.  The loose clamp can be pulled anytime.

I love my Valkyries, but I'm getting tired of Honda and aftermarket parts drying up, going unavailable, and no longer made.  I have a pretty good parts bin full of all kinds of stuff, but often not what I need.