Rear tire losing pressure, dealer stumped

[ecognomeist]

Hello! New member here. This summer, I acquired a 2019 Yamaha Tracer 900 GT. Overall, I really enjoy the bike, but I'm writing now for your advice on a problem that stumped my local dealer.

The bike is losing pressure from the rear tire. I offer some more details below, but the key points are

• I first noticed the problem on August 27.
• My last two measurements, about 48 hours apart, showed a pressure loss of 19 psi. I also noticed a measurable drop, from 36 psi cold to 30 psi warm, 2 hours into a ride.
• During a service visit on September 5, my local dealer was unable to find anything wrong with the wheel or tire, and they declined to offer any further advice about resolving the issue.

I am accustomed to checking tire pressures regularly, but having to re-inflate the tire almost every day is cumbersome and annoying. Moreover, the noticeable drop during a ride makes me concerned about safety and the longevity of the tire.

Since the dealer was unable to identify the problem, I was hoping someone here has any insights or suggestions. What should I do now?

Thank you!

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Timeline and dealer visit

August 27: as I was getting ready to ride the 150 miles or so to spend a few days with my in-laws. The front tire was a few psi below the recommended 33 psi, but the rear showed about 14 psi. I inflated the rear to the recommended 36 psi before departing.

August 30: heading out for a short scenic ride, I checked the tire again and found the pressure was again in the teens.

September 2: I checked the pressure before leaving for home. It was in the teens. I inflated it to 36 psi, and then checked the pressure at a gas station about 2 hours later. The pressure had already fallen to about 30 psi. I added some air and resumed the trip home.

September 5: I took the bike to my local dealer to diagnose the issue. Before heading to the dealer, I checked the pressure, and found it was around 14 psi. I inflated the tire to 36 psi. At the dealer, I was told that a technician inspected the wheel and tire, and then covered the tire with soapy water to locate any leaks. The technician reportedly waited 40 minutes to see if any bubbles formed in the soapy water. As you will see in the attached invoice, the dealer was unable to detect a leak in the tire. When I pressed them to explain why the tire was losing pressure, they were at a loss; they found nothing wrong with the wheel or the tire.

September 7: I measured the tire pressure at 17 psi.

[texscottyd]

A couple of pounds a week is irritating; 10 pounds a day is a big leak, and needs to get addressed ASAP.   

Assuming your dealer is accurate about there not being a puncture in the tire itself, the next two things would be either a valve stem leak (not too uncommon), or possibly a leak at the tire/wheel bead.   I would think the stem is the higher probability of being your problem, since it would have taken some kind of significant impact to effect the bead seal.  

If you have the wheel off the bike, you should be able to come up with some sort of a water dunk tank to get the valve stem submerged & look for air bubbles.   

Good luck! 

 

[betoney]

@ecognomeist - Remove the wheel from the bike, fill to about 40psi.  Fill the bath tub about 6-8" deep (wife or girlfriend might not approve of indoor mechanics...) a large wash basin will work as well.  Submerge the tire, standing it upright so that water is covering the sidewall/bead and air valve.  (legal disclaimer) - Do not lay the tire down to prevent water intrusion in the bearings. 

Rotate the tire every few minutes looking not only at the tread but the bead as well.  Continue to rotate until you have turned it 360 degrees.  If it is leaking as much air as you say then you should see some air bubbles.

[betoney]

17 minutes ago, texscottyd said:

A couple of pounds a week is irritating; 10 pounds a day is a big leak, and needs to get addressed ASAP.   

Assuming your dealer is accurate about there not being a puncture in the tire itself, the next two things would be either a valve stem leak (not too uncommon), or possibly a leak at the tire/wheel bead.   I would think the stem is the higher probability of being your problem, since it would have taken some kind of significant impact to effect the bead seal.  

If you have the wheel off the bike, you should be able to come up with some sort of a water dunk tank to get the valve stem submerged & look for air bubbles.   

Good luck! 

 

Ha- ya' beat me to it again... 👍

[texscottyd]

20 minutes ago, betoney said:

Ha- ya' beat me to it again... 👍

Consensus is a good thing.  Unless this doesn’t locate his problem...   

[betoney]

17 minutes ago, texscottyd said:

Consensus is a good thing.  Unless this doesn’t locate his problem...   

It HAS to be one of the things we mentioned.  My money is on the valve stem.

[YamaGeezer]

An added trick - mix some liquid dish soap in the water but stir it in gently so as not to make too many bubbles.  This makes bubbles on the tire easy to see, as it rotates out of the water.  Even a tiny leak will make a ball of foam that looks like frog eggs.  Good Luck - 

[Buggy Nate]

And get a new mechanic. They sound like a bunch of muppets.

[peteinpa]

That much airloss you should be able to hear it.

For on the bike mix a little Dawn into a spray bottle and work your way around slowly spraying tread, sidewalls, rim, (might be pourous or cracked), and valve stem including inside.

Look for the bubbles.

+1  don't let that shop even set your clock.   SAD.🤐

[ecognomeist]

Thanks, everyone, for the replies and the thoughtful advice. I'm seeing two main suggestions here:

• Use soapy water to search for a leak, either with a spray bottle or some kind of basin. FWIW, the dealer claimed to have checked for a leak with soapy water using the spray bottle method. They also claimed to have checked the valve stem.
• The inability of the dealer to sort the problem is evidence of incompetence. Find a new shop.

Let's say I find a leak. Are these the possibilities and solutions?

1. Valve stem. Can be fixed / replaced.
2. Sidewall. New tire.
3. Tread. New tire.
4. Bead / rim. New tire and / or new rim.

[trevinator]

if its on the bead, chances are it just needs to be cleaned up. my money is on valve stem, bead, or pinhole leak in the tread due to a puncture.

[knyte]

I've got a spray bottle marked "dishsoap & water" for just such occasions.  The trick is to use more dishsoap than you think you need.  If the solution is too thin, the water just rolls away and the bubbles aren't strong enough to remain & won't continue to form.

[BBB]

1 hour ago, knyte said:

I've got a spray bottle marked "dishsoap & water" for just such occasions.  The trick is to use more dishsoap than you think you need.  If the solution is too thin, the water just rolls away and the bubbles aren't strong enough to remain & won't continue to form.

Even better is if you can get your hands on some glycerol (pharmacists often stock it) as it makes really elastic bubbles. Add some of that to your dishwash/water mix and it makes them super-persistent. 

[Stew]

I'm staking a whole 50 pence (cents) that it's tyre (tire) valve related.

 

[Dirty Randy]

I have done this at my neighborhood pool ... people though i was some crazy guy 😄 .. HOA doesnt say anything about motorcycle tires in the pool ... definitely does now