R100GS tubeless tyre valve, what size is the hole?

bubbles · May 2, 2018

I'm slowly looseing air pressure from the front wheel tyre on my 1991 R100GSPD so just wondered if anyone here knows what size the valve hole is as some ebay suppliers give a rim size hole of 11.5mm, the existing valve dosen't look too well seated.

Or should I put a tube in and if so which one do you use?

Thanks in advance for any replies.

mikeyboy · May 2, 2018

Tis 8 mm
Quick eBay search will find the correct stem
If you decide to fit a tube 90/90 21

JJH · May 2, 2018

I had a r100 gs which gave the same problems. It’s a common enough thing. I took out the valve and cleaned around the hole and put in a new valve. Also cleaned around the rims. Fitting tube is admitting defeat. JJH

Beemerboff · May 3, 2018

Problem with experimenting with a few possible solutions is that the tire going flat can be a bit of a nuisance, particularly if you are at high speed and the bead breaks away from the rim!
Dangerous, if you need to be told, and it seems that there are some who do, and unless you happen to be towing a air compressor, almost impossible to blow the bead back on to the rim.
And of course no major manufacturer of motorcycle tires permits plugging them, so this tubeless thing all seems a bit pointless.

Redboots · May 3, 2018

I just drilled it out to the size of valve I chose... 10 years ago. All good.
I have also plugged more than one tyre when its in the center of the tread.

The only way is tubeless.

mikeyboy · May 3, 2018

I’ve been repairing tubeless motorcycle tyres since they were introduced,
never had an issue with a repaired tyre yet

JJH · May 3, 2018

Beemerboff said:
Problem with experimenting with a few possible solutions is that the tire going flat can be a bit of a nuisance, particularly if you are at high speed and the bead breaks away from the rim!
Dangerous, if you need to be told, and it seems that there are some who do, and unless you happen to be towing a air compressor, almost impossible to blow the bead back on to the rim.
And of course no major manufacturer of motorcycle tires permits plugging them, so this tubeless thing all seems a bit pointless.

I have 3 things to say in answer to this post. Wrong. Wrong. Wrong. JJH

ChasF · May 3, 2018

The valves are 8mm. I bought a bage of 20 metal stems from ebay and they are fine. I use fairy liquid/water mix applied with a paint brushtoeasilydetect leaks around the rim or at the valve - never had a leaky valve.

Recently took the tyres off to clean the rims and found that the main problem was a build up of rubber from previous tyres. Once cleaned both tyres lose about 1 psi a month.

VAL. H. · May 3, 2018

What they already said, But I add:

Fit 90o valve stems front and back. Saves a lot of grief.

Clean tyre seats with a wire wheel on a drill. Get them spotless and clean before refitting tyre. Done properly the tyre will not go down for years.

Fitting a tube to a tubeless. Can be done, but why would you considering the above. Also a lot of tubeless tyres are patterned or ribbed inside and this can destroy a tube quite quickly especially when running low pressures for off road.

Plug tyres if you see fit. But do it properly and be prepared to take the consequences if they arise. I've personally never had a problem/failier, car or bike.

Getting the tubeless tyre to seat can be tricky without a big compressor. When using an electric tyre pump, use a ratchet strap around the circumference to hold the tyre in the well to get an initial seal. With a few psi in it 10-20say pop the strap and the tyre should jump on to the rim seat.

Val.

Redboots · May 4, 2018

VAL. H. said:
Fit 90o valve stems front and back. Saves a lot of grief.

Indeed

JJH · May 17, 2018

If you are still looking for a valve I have one lying about. Off a Kawasaki gt750 I think. It’s there 20 years. It’s the old type that has a nut holding it in. Looks like a tube valve stem. Pm me your address if you want it. JJH

R100GS tubeless tyre valve, what size is the hole?

bubbles

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mikeyboy

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JJH

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Beemerboff

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Redboots

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mikeyboy

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JJH

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ChasF

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VAL. H.

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Redboots

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JJH

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