1988 K75S, Inlet Valve Removal Question

[jay1622]

Looking at a geat deal on a valve spring compressor kit and have a question for those of you in the know...

Will a 30mm adapter suffice for the intake valve (34mm)? I'm thinking it absolutely should, but want to see if you all have run into anything that would indicate otherwise.

Also, what have you used (assuming you did this) for a sleeve on the valve stem when installing the valve seals? I'm thinking a properly-cut good-quality straw. Thoughts?

[The Mighty Gryphon]

It looks like I will be going into my K100RS 16V to do the valve stem seals this winter so will be looking forward to any replies from anyone who has done this job.  Hope there is someone here who can offer a few tips.

[pfls]

I have a K&L valve spring compressor, which has several sizes of ends for different spring diameters. You can use shrink tubing on the valve stem to protect the seal. Usually it can then be pulled off and used on the next stem. Hope this helps.

[The Mighty Gryphon]

Couple things I am wondering about:

1.  Is it possible to pull the head with the engine in the bike?  I would rather not have to muscle the whole engine around the garage if all I am working on is the head.

2.  Is it ok to do the seals one valve at a time, or do I have to disassemble all 8 intakes and do the seals as a group?

3.  I am trying to correct an oil consumption issue.  I know the intake has vacuum to suck oil past the seals, but with no vacuum on the exhaust side, how important is it to do the exhaust seals?  Everything is fine but for using a quart of oil every 600-700 miles.

4.  Any tips on locating the cams during reassembly?  Is there a workaround for the special BMW tool for holding the cams in position?

5.  What parts besides seals should I plan on getting to do the job? 

[pfls]

1) Yes the head will come off with the engine in the bike.
2&3) You can do the seals one at a time, but why?  It is possibe to replace the seals with the head in place, if you charge the cylinder with compressed air to hold the valves closed, and have a way to compress the springs to remove the keepers. If I remember correctly, the factory spring compressor made that possible. If you are removing the head, I would replace all intake and exhaust seals, and lap the valve/seat contact area. That way you can inspect everything.
4) Start with the engine on tdc on cylinder 1, with the valves on overlap, like you would do to change a shim bucket. Zip tie the chain to the sprockets before you remove them. Once you get the head back on, reinstall the cams in the same position you found them, using the 19mm hex flats on the cams to manipulate them enough to get the sprockets located.
5) You will need the head gasket, coolant, and valve seals for sure. I would think about replacing the valve and crank cover gaskets, since you will be removing the timing cover. You will need sealer for the cover, and you should consider replacing the seal behind the hall sensor, since you will be disturbing it. This seal is tricky to install without the factory seal installer, and that might be expensive. Get exhaust gaskets as well. Depending on your milage, this would be a great time to replace your timing chain and rails, although it would make realigning everything on reassembly more difficult for you.

[The Mighty Gryphon]

Thanks for the tips.  They are just what I'm looking for.  Good to know I can get the head off with the engine in the frame.   Since I don't have any other engine work to do, it's nice to have to just handle the head itself. 

Plug readings look like most of the oil is going into the cylinder.  Compression is very good so I am thinking the rings are good.  My philosophy is if it isn't absolutely necessary leave well enough alone so I am inclined to leave the exhaust cam and valves alone on this go around.

Have inspected the cam chain already and the chain, tensioner and guides look to be in good shape so shouldn't need attention at this point. 

Overall, the engine with 109,000 miles on it starts without hesitation, runs strong, and shifts smoothly with the only issue being oil consumption, and oil fouling on the spark plugs. 

The only other job I need to do on this bike besides fluid changes is replace the clutch o-ring to correct some very minor leakage there.  Pretty much everything else was addressed last winter.

Considering the miles, I am pleasantly amazed at how durable these bikes are.  Even with the oil usage, I wouldn't hesitate hopping on her tomorrow and riding to the west coast.

[rbm]

... You will need sealer for the cover, and you should consider replacing the seal behind the hall sensor, since you will be disturbing it. This seal is tricky to install without the factory seal installer, and that might be expensive.

Tip I picked up from the forums:  As a replacement for the BMW tool, use a plastic pill bottle that will just fit over the crank end.  Mount the seal on the pill bottle with the lip facing properly, tap the seal into the cover with a suitably sized PVC pipe, and pull off the pill bottle.  The seal will be left with the lip inwards.

[pfls]

That sounds like a great way to get by without access to the shop tool. I'm going to find and set a pill bottle aside now for when I need to replace that seal again.