bwellervt Posted June 21, 2009 Share Posted June 21, 2009 Hey All, My first post here. Thanks for having me. My bike is a '76 XS500C. BACKGROUND: So, down to business: I recently had a break down on the way up a twisty mountain road here in VT when I shifted into a false neutral between 3rd and 4th during a pass. Over-revved the motor, and blew out 3 of the 8 valve tappet adjustment screws on the rocker arms. Limped her up and down the mountain, got closer to town, tire locked up as expected. Grabbed clutch and coasted her into a country store to call a buddy. FIRST STEP: This was all two weeks ago. Since then I pulled the valvecover... Found 2 of the 3 adjustment screws, and 3 lock nuts... That's right, 1 screw is MIA in my mill. Fished and fished, drained the oil, flushed and flushed again. No screw has surfaced. I found a slightly longer adjustment screw from a more modern Yammy to fit. Slapped it all together. Set clearances x8 valves. Locknuts tightened down good. (Can't fit my torque wrench in the tight space, though!) Valvecover back on, new oil filter, new oil. PROBLEM: Started up the XS after putting her back together. Sounds great. Some valve noise, but sounds like everything is working as it should. The bike starts easily and quickly now. After warming the bike up, I took her for a rip down the street... At 5500 - 6500rpm, the motor produces severe vibration. Enough to numb the hands almost instantly. SUSPECTED CAUSES: - bad job setting valve clearances (doesn't seem too likely to me) - bent valve(s) - balancer issue (Is that part of the balancer I see through the oil fill? If so she ain't moving with the motor!) - loose motor mount Any input will be greatly appreciated! The warm-weather riding season is short in Vermont, and I want to get out and ride. Thanks a lot. --Ben Quote Link to comment Share on other sites More sharing options...
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