XR650L top end

[HellSickle]

After completing the 5MOH (5 Miles of Hell) trail in Utah, the HellSickle died. I've got spark, valve lash seemed OK, nothing wrong with the carb.

I pulled the valve cover last night and the decompression mechanism/anti-kick back seem a little flakey/sloppy. I'll pull the cam tonight and see if there is some wear or a broken spring in there. Has anyone had issues removing these from the -L? With only electric start, I'm not sure if I should even worry about these things. The only thing I can think of is that it may be harder to bump start if the battery or starter dies. If the decompression mechanism is a reliability concern, I would say that it's probably the greater of the two fears. (We spent a half day with a team of 6 folks to haul the beast out of the canyon where it died)

The cam chain seems slightly stretched, but the valve timing is OK (maybe off about 1/4 tooth's worth due to stretching). I'll replace the chain & tensioner while I'm in here. Should both sprockets be replaced as well?

Here's where the creeping-repairism comes into play. As long as I have the cam out, it's not much more work to pull the head. I'm thinking that at nearly 30k miles, the valves and piston could use a good going over. Is the '94 an iron cylinder? I think the nikasil was discontinued after '93. If iron, I'll go ahead & bore 1-over and put in a new piston & rings.

I'm not going with the hot cam & high compression piston. I value durability & reliability more than performance. I'll stick with the Honda OEM parts.

-Jeff-

[XR650L_Dave]

JD, don't forget 4strokes.com and the yahoo xrlug groups- lots of info over that way as well.

dave

[HellSickle]

Update:

I found massive amounts of loose carbon in the cylinder & head. I'll bet that there is was at least a couple of teaspoons of loose stuff in there after I pulled the heads. A solvent test with the valves showed them to be really leaky. I'm gonna pull the valves & give the head a good cleaning.

The cylinder looks really good. I'll pull it & measure the bore. I don't think it will need anything other than a fresh hone & a ridge ream for the new rings. The cam chain & sprockets will be replaced.

-Jeff-