moto guzzi mag wheels tubeless conversion

[arveno]

I have a set of mag wheels from a 1990 california III and i would like to use them tubeless.

I did use the search to find info on how to use them tubeless and found that this valve stem from Harper is what i need :

http://www.harpermoto.com/tubeless-valve-stem.html

Can I use these instead ? ( i do not see a big difference .)

http://www.ebay.com/itm/NEW-PAIR-Tubeless-Tire-Valve-Stem-Steel-for-Scooter-Motorcycle-ATV-Moped-Go-Kart-/221500810789?hash=item33927a2625:g:N0kAAOSwVFlUFmyn&vxp=mtr

How about the rubber one ?
http://www.ebay.com/itm/BIKEMASTER-Motorcycle-Wheel-Rubber-Tubeless-Valve-Stems-151563-4-Pack-/121275572114?hash=item1c3c965f92:g:bScAAOSwLVZV10hm&vxp=mtr

what else do i have to do ?

thanks
Marco

[fotoguzzi]

I used a tank valve (I think thats what they called it) got at the hardware store for about $5. it came with a tap so I threaded the hole and it screwed in with a little sealant.

[arveno]

just found this uses full thread

http://wildguzzi.com/forum/index.php?topic=67269.0

[Groover]

I thought the Cal3 rims were of tubeless designation already? What are the markings on the rims?

Either way, I used the Drag Specialties type on my 81G5.
 
http://www.motorcycle-superstore.com/22509/i/drag-specialties-metal-valve-stem?WT.ac=SLIsearch
 
Drag Specialties: Part: VS-1218R
 

Hope that helps
 

[charlie b]

Yep, same kind of stem on mine too.  I did have to turn down the diameter of the part inside the wheel to fit the recess in my rims.  I only used the rubber part on the inside of the wheel.  Also applied some RTV around it when installed.  They have been on my bike now for about 50k miles with no issues.

[Groover]

I also used the inner seal only and a little RTV. I'll probably turn the rims down next tire change as I didn't quite like how the rubber squished unevenly to follow the curved shape of the rim. It works though, on year two now and all is well. I did have to also cut the valve cap a few mm so it would tighten all the way. The valve stem itself could be a little longer for these conversions. NAPA has one that also works and the stem is longer on theirs. I have the part number somewhere.. I'll post next week if needed.

Edit: I used two nuts back to back to lock them which is why I had to cut down the cap a little. Otherwise, the cap would have fit fine.

[Perazzimx14]

NAPA also has screw type valve stems for a couple of bucks each.

[Tom]

1990 Cal III mag wheels should tubeless from the factory.  IIRC.  '91 mag wheels are definitely tubeless but with Guzzi, you never know.  You won't know unless you take a look at the rim and the valve stem.  You'll definitely know when you pull the tire off.