Motorcycle Repair: Motorcycle tires with inner tubes., mail order catalogs, size tubes

Question
The impetus for this question is actually the TLR. I've had it and another bike (XL600R) have problems with front tire flats. Both bikes were purchased used and I've replaced the tires a few times (at home, glutton for punishment). I have had, on two occasions, front tube failures at the valve stem. I've been cautious in mounting tires. The tube is placed in the half mounted tire first and inflated to let it get distributed properly in the tire. I'll let some air out to get it a bit saggy, then finish the tire mounting. I'll fill it a bit over the running pressure then check the bead, if it isn't seated I'll remove the valve stem and blow it up then bounce the wheel on the ground while rotating it. I use tire irons, avoid pinching the tube between them and the rim as well as between the rim and tire.   I'm careful at lining the stem up with the rim and rimstrip holes (I replace them also if they aren't nice and pliable or otherwise damaged). I also  install the correct size tubes, that should go without saying, but I've heard of stranger things.  


I read somewhere it may be due to mounting the tube improperly when it fails at the stem. I've been changing tires ever since I could successfully run a bicycle into the hedges and haven't had this problem other than with the tubes with locking nuts on 'em. Both of these bikes were bought used and had that style tube in them. I've got a CB750K with the same and it has never had that problem (but then again it isn't getting chucked around in the dirt. Both of affected bikes have been ridden hard in the dirt, the TLR hasn't exactly been babied over jumps with it's short suspension travel.

Anyhow, what am I doing wrong?  It seems that all the tubes I purchase, either from the dealer or the mail order catalogs, have that style valvestem.

If I may say so, this is a great idea for the web and I'm glad I stumbled across it.

Thanks,

JImmy

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Followup To
Question -
I've searched the net and can't find the answer to this relatively mundane question...
In the process I found a question you had answered about tire changing, hence my pestering you with this one.

On bikes with inner tubes, why do some tubes come with a pair of locking nuts and others don't?
Why bother installing the nuts? I've got an '02 CRF 450 and it doesn't have them, but on my '86 TLR200 (Honda psuedo trials bike) there are locking nuts on the tube's valvestem.
Answer -
Hi Jimmy,

I couldn't agree more.

Their function is to keep the stem aligned with the rim and prevent tube from moving on the rim.

Why some tubes do not have them is better rim/tube designs. Not to mention common sense and production costs. : )

Respectfully,
Mark Shively  

Answer
Jimmy,

Only things coming to mind is defective tubes, imperfection in tire or wheel, spoke end, foreign particle in tire/wheel strap, ect...

Clean inner tire walls and wheel prior to tube installation. Feel inner tire and wheel areas for sharps.

Send me an email. I'll return several files on tire changing that may be helpful. My email addy is:

mshively1@woh.rr.com

Mark