Tach seal 1981 750k

[barelycompetent]

I have heard that to replace the tach seal on my 1981 750k, I have to remove the valve cover.  Can it be done without removing the valve cover?  If it cant no big deal, but when I put the valve cover back on do I have to tighten the bolts down in any certain order, and torque them to any specific specs?  If anyone would mind walking me through this procedure step by step I sure would appreciate it!

[shinyribs]

I haven't looked at the FSM concerning any torque numbers/patterns,so this may be bad advice.

Whenever I tighten down any type of cover that is long or has several fasteners I always start in the center and criss-cross my way out to the edges. Something like this I would probably do in two stages: one snug down pass,then a final tighten down pass. The fasteners in question here aren't very big so I'd just give them a decent snugging with a 1/4'' ratchet and call it a day. Say, a little tighter than a spark plug but not as tight as a handle bars clamp. Check back in a few heat cycles and if they seem to have loosened give them another snugging. These are not under any sort of stress and the gasket won't take much pressure to seal so no reason to get crazy with it. It's much easier to retighten and loose fastener than it is to drill out a broken one.

Sorry we left you hanging.

[barelycompetent]

Thanks Shiny, you guys didnt leave me hanging lol.  Well I got the seal in a week ago, then took the valve cover off and everything was going great till I went to put the valve cover back on.  Thats when I discovered three of my cam bearings were stripped out and I couldnt get the cover back on tight.  So took the cam bearing out, ran down to the local shop and they were able to put helicoils in for me, but more bad news, in the process of taking out the cam bearings two of the holes in the block stripped out.  So now they need the whole bike to put helicoils in the block for me, did I mention that I had sold this bike and was only supposed to be putting in a tach seal, because it was on order before the kid came over and bought it?  Well 90 bucks later, the helicoils were in, the tach seal was in, and the valve cover was back on and tightened down properly.  Go to hook up the tach cable, and the bolt holding that in was stripped.  I didnt tell the kid that part.............sheesh lol, still made money on it, and learned a valuable lesson in NOT working on anything ever again once its sold lol.

[LukeM]

If you are referring to the seal where the tach cable attaches to the valve cover, there is no need to remove the valve cover.  The seal can be removed with a pick (not a guitar pick, but a pointed metal pick).  I had one fail on my old '79 750L, and it took a bit to get it all out.  Easy job, just a little tough to get to.  Might want to search our archives for "tach seal" and see what you find.  This should give you a good start.

Good luck.
Luke M

[barelycompetent]

Got it all squared away!  Thanks Luke, the bike is somebody else's garage now!  Now I'm eyeballing an 81 Yamaha xs650, wanting to do another cafe!

[LukeM]

Glad you got it done.  The bolt, if overtorqued, does a number on soft aluminum. Just needs to be snug enough and let the seal do its job.

Sometimes it's best to cut your losses, and move it down the road.  Good luck with the next project.
Luke M