Bad Maintenance Day for my 426

4 replies to this topic
  • BASSic

Posted May 05, 2008 - 06:49 AM


Yesterday, I attempted to install a new timing chain and a 03 450 exhaust cam on my 01 YZ426. Just before I took the cam cap bolts off, I figured I'd just check my torque wrench to verify that it's working properly. I put a spare bolt in a vice and set the wrench to 30 in-lb, turned, turned some more (shouldn't this be releasing by now?) and SNAP I broke the bolt. Maybe the torque was set so low I didn't hear/feel it release?

I figured that since my cover was already off, I could at least check the valves. I pull out my feeler gauges and realize I don't have the ones I need! I need smaller gauges to measure intake valves.

The good news is that my exhaust valves are still in spec: .205 mm, which is near the minimum allowed clearance, but still in spec! According to the previous owner, the valves have never been inspected or adjusted.

Once I figure out this torque wrench, I'll be doing the cam swap and from what I hear I'll have to adjust the valves anyway so I'll try to put them in the middle of the range.

  • Birdy426

Posted May 05, 2008 - 07:26 AM


At really small torque values, the click is really subtle, and not really even have to sort of feel it...

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  • grayracer513

Posted May 05, 2008 - 08:43 AM


+1 on the torque wrench. 30 in/lb is next to nothing.

On the feeler gauges, I've never had any trouble using standard 4" automotive feelers in a 426/450. But if yours are wider, just trim a little off one edge with a pair of sharp scissors.

  • BASSic

Posted May 05, 2008 - 10:20 AM


It's not that they're too wide, they're too thick. The smallest I had was 0.20mm, which is the lower limit for the exhaust clearance.

  • Birdy426

Posted May 05, 2008 - 09:33 PM


Most feeler gages will work, but the Motion Pro angld jobbies sure make the task easier...http://www.motionpro.../partno/08-0392 They come in .002/.003, .004/.005, and .006/.008 inch thicknesses.

Most shops carry 'em

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