Mods for the 110, You can start with an aftermarket frame. You will find a used hardtail aftermarket frame before you find a suspension aftermarket frame. Wheels, tires, fenders and seat. There are fiberglass fenders being sold on ebay now if you want to paint or change the colors of your 110. Engine mods. Exhaust of course and you can still find NOS aftermarket exhausts, I have a NOS Bassani exhaust that hasn't been made for years so the parts are still out there. I just sold a 125 big bore higher compression piston kit that had the piston, rings, wristpin and headgasket. You can have head work done, larger intake valve, polished intake and exhaust and mild porting too. You can change your rear sprocket, but the big killer for power is that stupid hi/lo gearbox. If you were modding an atc90, I could tell you what engine cases to use to get rid of that hi/lo gearbox and have a manual clutch too, a major improvement in performance and a manual clutch can be made to take way more power than those wimpy semi auto clutch set ups. You could run a bigger carb if you had an aftermarket intake. They are getting tough to find though and will take alot of looking. You could get a stroker crank and pushrod. Not cheap and I don't know of anyone doing stroker conversions on a 110 nowadays. You could bore out your cylinder, have a custom sleeve made and really run a large bore piston. Also not cheap and there are only a couple pistons that would work. You could cam it up, but what's the use unless you change all the other things too. You could change the airfilter and ditch the restrictive air box. You have to watch about running through water unless you use one of those "outerwears" covers for your filter, but don't forget, they are not 100% waterproof. Performance costs money. And if you trick an engine out, it's still a hardtail unless you have an aftermarket suspension frame. And all the money it would cost you, unless you are absolutely insane like a couple of us, the money would be better spent on a 200x that has suspension and a bigger engine stock and disc brakes and such. Enjoy the 110 for what it is. If you want more engine and a hardtail, go with a 185s or 200s. Heck, I could even sell you a suspension frame for one of those engines. Or go the 185s/200s engine in a 200x frame if you can find a cheap roller and have an auto x. It's way cheaper and easier. Real performance for the old hardtails is best left to the three wheeled insane like me. And don't forget to hop up one of the old 90/110 hardtails---Pry your wallet open. And that is even if you would take the time to find most of these parts in the first place, they just don't grow on trees anymore. If you want to do it for cheap, it won't happen. Not if you want real performance anyway. Just sell it and buy a bigger trike.
Nicholson 500x (Project)
Nicholson 185s
Nicholson 110 (That takes an atc70 tank)
Ascott 500 head/350x (Project)
Homebuilt Racer Chromoly Suspension 110 (Ragin Runt)
PK Racing Suspension 70
A+ Inc Suspension 70
AWS Aluminum 90 frame
Hi Performance ATC Suspension frame rd350
Hi Performance ATC Suspension frame 90