converting to tubeless - valve stem hole question

[Andrew Vanis]

Going tubeless on the '81. It has smaller tube valve stem holes than the '83 GS's I have.

Do I just drill the '81 out to the same diameter as the '83?

Also the '83 seems to be countersunk from the inside.

All these are aluminum wheels. the '81 says on the rim that it is suitable for tubeless.

[Eli69]

i'm not exactly sure about your situation but i can say that i've drilled out the holes on a few rims and inserted whatever valve stems i could find and so far they're working. i was pretty careful about the size of the hole and making it smooth. it's been a while, no problems...

also this is on rims for a '78 GS1000 which isn't even supposed to be tubeless.

[bwringer]

No, you don't hog out the holes. You install the correct valve stems.

Yes, lots of people have just drilled out the holes and installed car valve stems, and most have not died horribly. But it's not the right way to go about it.

You need motorcycle valve stems, not car valve stems. These are the same diameter all the way down. Car valve stems are fatter at the bottom. Car valve stem holes are .453" diameter, and GS valve stem holes are about 8.3mm (.325") diameter. (Most modern era bikes actually use the car size.)

https://www.napaonline.com/napa/en/p/NTH90426/

To really do it right, you need to machine a flat face on the inside of the rim. I have a counterbore and pilot I use for this. A few seconds with this in a cordless drill are all it takes.



Here's the counterbore and pilot -- it's a 5/8" counterbore with a 5/16" pilot. I ordered these from an airplane tools web site:

[mmattockx]

I just converted my 1100E to tubeless, front and rear. I used these valve stems:

http://www.motorcycle-superstore.com/44692/i/bikemaster-chrome-tubeless-valve-stem

They are working fine so far.


Mark

[Andrew Vanis]

So I love the countersink tool

I got the valves Mark shows.

here are pics of the different holes I'm working with - https://goo.gl/photos/RXjHWFJHDXoZG77FA

the 83's have the larger main hole and the the countersink as well. into that the pictured valves fit well.

On the 81 (the smaller hole) the hole is wide enough for the valve but not wide enough for the raised lip on the rubber piece (last picture)

I'm thinking of making the 81 hole same as the 83 holes - larger main hole to fit the raised rubber lip. May also add the countersink on the front wheel since it is curved. the rear is flat so I think that should sit well.

[mmattockx]

On the 81 (the smaller hole) the hole is wide enough for the valve but not wide enough for the raised lip on the rubber piece (last picture)

My front wheel was like that, too. I just guided the raised lip into the hole as best I could and tightened it down. It sealed ok like that and is solidly held in place. With the internal curvature I would be concerned about sealing with the raised lip piloted into a larger hole and spot facing it wouldn't leave much material behind. I did think about taking a countersink bit and putting a bit of a taper on the hole to capture the raised lip but figured I would leave that as a last resort if it didn't seal as-is.


Mark

[wymple]

Some rims conveniently have just the right size hole that you can simply run a 1/8" NPT tap thru it and just screw in a tank valve with a bit of teflon tape. Just did one a few days ago on my Guzzi. On my GS850 I used the valve types being shown by previous posters, not sure now if it was necessary.

[chuck hahn]

No drilling ..no BSing around. Rubber washer goes to the inside and done. Been running them for years without a hitch.

https://www.powersportsplace.com/parts/bkm-15-1947?seid=pspse1&cm_mmc=pla-google-_-shopping-_-pspse1-_-bikemaster&gclid=CjwKEAjw3Nq9BRCw8OD6s4eI5HASJABsfCIaKPU73xUL22IUIsjOCICET9Cn5KKcEgyb7KTmVrVMPRoC2q7w_wcB

[alke46]

Good info here. I suspect more of us will be doing this at the next tire change.

[chuck hahn]

Wire wheels of course will need tubes and rim strips. Many dirt bike forums say they are running tubeless spoked rims by using this tape to seal the rims. I havent gotten the nerve to give it a go though myself.

http://solutions.3m.com/wps/portal/3M/en_WW/VHB_Tapes/Home/Products/three/two/

[Andrew Vanis]

the radius of my beveled section would not provide a sealing surface. the samples shown above by others have flat areas.

I ended up countersinking a 5/8" and the edges needed to come down over 1/8" to get to the level of the middle.

My drill bit doesn't have the flat area like the cool counter sink tool above but its what I had. I'll give this a shot an see what it does.

[nejeff]

No drilling ..no BSing around. Rubber washer goes to the inside and done. Been running them for years without a hitch.

https://www.powersportsplace.com/par...VMPRoC2q7w_wcB

Are you saying you don't use a counterbore?

[chuck hahn]

Nope.... put them in and move on. Havent had a leak or anything yet. Some folks advocate using bead sealer on the washer just to be sure...which I havent done that either.

[Andrew Vanis]

i think it makes a difference if one has the valves with the raise rubber part and/or if you are installing on a flat or originally-curved wheel. if one is installing on a flat section and a flat valve washer, it seems a straight install without any drilling would work just fine.

The later rims seem to be spec'ed for typical rubber valves (car style) and the chrome replacement valves are designed to fit those types of openings.

[limeex2]

No drilling ..no BSing around. Rubber washer goes to the inside and done. Been running them for years without a hitch.

https://www.powersportsplace.com/par...VMPRoC2q7w_wcB

This method works and has been used for years.