I'd like to order some Acerbis hand guards, for my klx351sf. Not sure what size fits our bike? 22mm or 28mm. What else needs ordering (presumably some new grips?) Not by my bike as i'm on vacation, so unable to measure, but my current handlebars are all stock. Given they come in either 22mm or 28mm. What size are our handlebars?

I wouldn't even mind changing my stock handlebars to protaper. Just need to research a little more on best fitting size dimensions and all. What do most people go with? or is it complete personal preference on the protapers ? I find the stock position comfortable, so if it aint broke......... But then again, i've not tried anything different.

 

I use 7/8" (22mm) Protaper CR high bend...like them a lot.
You'll need an adapter if you go to 28mm bars...but it can easily be done.
22mm bars have the cross bar with a pad, the 28mm bars do not. Bikemaster and such have a kit to swap from 22 to 28mm.
FWIW, the stock bars are not an easy choice to mount hand guards to because of the welded plug in the end, but it can be done.

 

I got the Renthal fatbar 1/8(28mm) (RC HONDA CR/CRF 04-13KAWASAKI KX/KXF 06-13) with the Protaper universal fat bar clamps.

 

I have Acerbis on my stock bars and I just tapped that welded plug and threaded the bolts right in. Worked great and no problems, the guards are all banged up and I've had to bend them back a few times but the bars survived.