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Thread: No Spark, No Gas, No GO!

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    Senior Member pdksh's Avatar
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    Nov 2016

    No Spark, No Gas, No GO!

    The saga between me and my XT has been a little tumultuous over the past six months, so bad that I picked up a Yamaha SuperTenre. In the spring I was blasting down a country highway, about 30 minutes from home when the bike cut out, dead. It was like someone had pulled the key out of the ignition. At the side of the road I was unable to start the bike, the SPARK PLUG clean feature worked but no spark when cranking. This assured me my coil/plugs/wires were fine but I had no spark when trying to start the bike. I immediately suspected a bad crank sensor (2008 model) and/or a broken wire in the wire harness. So once again I hitched a ride home and picked up the Uly with my trusty trailer. This was the third time in so many seasons I needed to trailer her home. I was not a happy Bueller.

    In the garage I discovered no fuel/gas in the front cylinder and an abundance of fuel in the rear cylinder. I would get an intermittent spark when wiggling the wire harness while cranking. Obviously an electrical problem. Grounds - CHECK, Rechecked and CHECKED again. I found three wires in the main wire harness at the triple clamp that failed the "tug test". One of the wires was an ECU 12v or 5v (grey I think) so I was pretty confident I had a fix. NOPE... Replaced the crank sensor. NOPE... Replaced the ECM (it's an ULY afterall) NOPE... Replaced the TILT sensor, Dash... NOPE... I have an 07 XB12R that shares about 90% of the electrical components to swap parts from. I patched EVERY wire in the main harness at the triple clamp that had anything to do with making the bike go, metered for shorts and opens... NOPE... NOPE... NOPE... I was in the Yamaha show room asking about their finance rates.

    I was perplexed about the fuel issue, obvious fuel in the rear cylinder but the front cylinder had no fuel. I had metered the injector wires and they tested fine. The motor was still in the frame so I gave the bike the poor man's compression test. Thumb over rear spark plug hole while cranking; NICE SUCTION POP. Thumb over font spark plug hole while cranking; tiny pussy fart... HRMMM... NOT GOOD... So I rotate the motor and pull the heads. The heads are fine, no obvious signs of things bashing into things they shouldn't. Push rods look good... The front cylinder has a vertical score that you can barely feel with your finger nail. Found the reason why my Uly likes burning oil but not enough damage to cause such an obvious loss of compression. Pulled the valves out of the heads looking for a bent valve, all looked good. Bike has 30,000 miles and I like to ride aggressively so things look as good as expected. Lapped the valves, and replaced the valve seals. I ordered a used JUG from FLEE-BAY to replaced the front cylinder with the score but that was a waste of 100 bucks. I didn't want to spend the money on a 1250 kit. The price of parts and machine work to bore the cylinders to 10 over was pennies less than the 1250 kit. Apparently motorcycle top ends are now just as disposable as cell phones, who knew? I took a three legged hone to the front cylinder in traditional backyard hackery! (yes it should bring tears to your eyes) You can still visually see the score but I can't feel it with my finger nail. I'm sure an egg is truer than my front cylinder. I'm arranging pickup of the SuperTenere with the dealership.

    If your still reading this post I applaud your patience. This is all over the period of six months. In the spring, shortly after the ULY died I was hit by a distracted driver that broke my right Tibia and Fibula. Two surgeries, a steel rod and now learning to walk without crutches. I wasn't moving to fast. A real crumy summer.

    Time to button up the Uly and see if I have spark and compression. With the motor at Top Dead Center (TDC), jugs on and installed the rear rocker box, all as it should be. The bike hasn't had oil in it for months but I let the lifters bleed down anyway. I start to install the front rocker box but the exhaust valve is open a pinch. The motor is at TDC and the exhaust valve is open? The push rods are properly installed but the front exhaust valve is partially open. I rotate my motor over and there is absolutely no rocker/valve movement on either head! The exhaust valve of the front cylinder is open a hair, the rest of the valves are closed... Off comes the rear rocker box and there's no push rod movement when turning the motor over for either cylinder. I pull the front jug off, visually inspect the lifters. One could have collapse but all four? A collapsed lifer won't hold a valve open. I know the lifters have to pump up but... I reached my finger into the gear case through the lifter hole and feel the front cams lobs while I rotate the crank. ABSOLUTELY NO CAM MOVEMENT AT ALL while turning the crank... My heart sunk into the floor, my engine was toast. I pulled the oil pump and gear case cover to inspect the damage as I calculated what my Buell was worth in little pieces. I had taken delivery of the SuperTenere and ordered aftermarket engine guards for it.

    I should have put this paragraph first and saved you all a lot of reading...

    With the gear case cover off and oil pump off the issue was finally clear. After months of chasing red hearings and throwing parts at my bike I found the problem. The Pinion Shaft Jam Nut that secures the pinion gear to the crank (and oil pump drive gear on pre 08 bikes) had backed off and the pinion gear was turning free. My issue was never electrical, it was 100% mechanical. I knew Buells, both the XB and 1125 suffered from loose crank nuts on the stater side but I didn't know about the pinion nut on the cam side coming loose. A 99 cent woodruff key and a 2 dollar nut was the issue. I could have saved the jam nut, the piece of mind was worth the two bucks. If I had not pulled the top end apart already I would have had too, anyways to insure the bike didn't have an impromptu valve adjustment. I was spared by the Buell Gods! My engine hadn't hammered itself to death. Couple of fresh gaskets, drop of red lock tight (more like a healthy squirt) and torqued the pinion jam nut to 70lbs. I buttoned the bike back up and couldn't wait to see if she would run. At 11pm with open headers I hit the starter button. The Uly fired right up after being in pieces for months. The engine rumbled to a nice potato-potato idle. FINALLY!!! My Uly was alive, the Uly has been my daily rider for years. The SuperTenere has some large tires to grow into.

    Thank You for reading, and re-torque your pinion jam nut.
    Last edited by pdksh; 01-16-2022 at 02:12 PM.

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