Saturday, May 15, 2010

Kerthunk! What the heck was that ?!?

In the riding to and from work since my first DAU Tech Day, I had heard and "felt" a pretty noticeable metallic banging noise.  I always felt it at the forward edge of my seat and it was quite disconcerting as you can imagine.

Each time, I'd pull over and look for loose items directly below the seat area since that's where I'd feel the impact.  Nothing found.  My mind would then race through all the possibilities, usually involving a failing gear train or engine parts slowly tearing the whole thing apart perhaps.

First time, I found the lid to the small ammo can I use as a wiring junction box to be loose, wheeeew I said to myself, it was just the lid bouncing up and down.  (though even then I wondered why I felt the impact under my seat".

Next time I rode Natasha, it happened a couple more times and it was starting to really worry and annoy me.  More close inspection of the area below the seat and behind the engine.  Nothing!  I convinced myself that it was the center stand legs being bounced loose during travel and the return spring on them banging it back onto the motorcycle frame.  To prove the theory, I zip tied the center stand to the frame and went for a test ride, no banging noises! 

The next day, however, proved me wrong.  Natasha exhibited two quick loud mechanical banging noises in a row as I was making a right turn and at the same time I started losing power; I could not go faster than about 35 mph!   I found a place to pull over but no obvious signs of damage once again.  I didn't want to be late for work so I continued on.   Engine performance was OK for a bit but less than 2 minutes later I started losing power again.

I then looked down at the trip meter and realized I had gone over 250km since the last fill up!  Dumb ass, I had forgotten to engage the fuel lever into the Reserve position!  Once that was done, I had good power once again and I pulled into the nearest gas station and filled up.   The good thing was that the loss of power thing was NOT associated with the loud metallic klunking noises!

I sent out a help message to the DAU and responses came quickly back suggesting things to check.  One of them struck a chord with me, when Craig suggest back-tracking on what I'd done during Tech Day.

Once I got home, I started on the front wheel and damn if it did not exhibit a very noticeable metallic rubbing sound when I spun the tire!  I dismounted the tire and was shocked to see one of the brake pads hanging only by one of two tension springs!

 The end of the spring is embedded into the braking material, not resting on top

I know Urals are tough but for the front wheel to be able to roll without noticeable problems and STILL brake is amazing.

Yep, it was the loose brake pad, probably getting moved by forces while I rode that would once in a while get free enough to klunk around inside the wheel hub.  This would cause the loud klunking noise and the it would just settle for a while until next set of right forces got it loose again.  Damn.

I called around the nearby area Ural dealers with no luck.  One didn't return my calls and the other did not have it in stock!  It was a $5 item and my Ural couldn't be ridden safely without it.  Craig, a fellow Uralisti then emails me and says to go down to the BMW dealer and ask for a brake pad spring for a /5 motorcycle!  He'd heard that they worked just fine.

What the heck I said to myself, the Russians copied the Germans as it was back before WWII, it should work.  I called the dealer and had them set aside a spring for a 1975 R75 Airhead Beemer.

I picked up the part after work on Thursday and it was BMW PN 34-21-1-457-091.  It was slightly shorter in length than the Ural OEM spring but it worked just fine.  In a matter of minutes, my front brake assembly was back together, wheel on and mounted securely.  Not only that, but the part was only $3!  Yep, amazingly a BMW part was cheaper than a URAL part.

I rode to work yesterday, Friday, and no loud metallic klunking sounds!  I was a happy Uralist once again.  My thanks my fellow members of the DAU who offered advice and suggestions.  Big thanks to Craig for getting me to retrace my steps and mentioning the bit about a BMW /5's motorcycle's spring working as well for the Ural!

Today was maintenance day again for Natasha.  She's a bit over 19,000 Km's, so I changed out her oil filter and engine oil, gearbox oil and final drive oil.  About an hour's worth of work.  Then I placed 2 ounces of Dynabeads in each of her new tires to balance them out and hopefully get them to wear evenly.  I must say, it was easier to put the dynabeads into the new inner tubes than the Russian one that came with the Uralshina tire on the front wheel!

Later on in the afternoon, I had an eye appointment for computer reading glasses.  Afterward, I headed to nearby culdesac hill (that's my name for it anyways).  There were tornado warnings to the east of us and there were some interesting cloud formations in our vicinity.

The ground conditions were good, not muddy at all off pavement, so I was able to ride Natasha up a very small hill nearby to pose her thus:

Natasha out in the wilds of Arapahoe County's suburbia


RichardM said...

Nice shots of the storm clouds.

It's pretty amazing that the front brake continued to work even with the spring mangled up like that. And it is even more amazing that the Beemer part was cheap!

Gary France said...

Who would have thought that you could use a BMW part to fix a Ural problem? I am pleased you fixed it and were able to give us another ride report.

Unknown said...


I'm glad your brakes didn't fail without the spring attached. Perhaps it is better with the shorter spring as it would be less prone to "fall" out of its groove.

Wet Coast Scootin