My Exhaust Valves Are Way Off

[TimTyler]

Finally got around to checking the valves today. It's the one thing I haven't looked at regarding my poor idling problems, even though it should have probably been the first thing I checked.

The intake valves all measure out to 0.15mm.

The exhaust valves... not so much. I got 0.09 / 0.13 / 0.10. Ouch. They should be 0.25 - 0.30.

I've ordered the "homemade" valve tools from Ken.

Do I need to know which shims are currently in place before I can order new shims? Is there a way to tell without the tools or PO service paperwork? What's the math?

The cover gasket seems in excellent shape and I'm assuming it can be re-used. I cleaned a thin brown sealant/adhesive off the gasket and cover. What was that? I can see it being helpful getting the whole thing back together again.

Thanks in advance, Oh Wise Ones.

[Inge K.]

Do I need to know which shims are currently in place before I can order new shims? Is there a way to tell without the tools or PO service paperwork? What's the math?

No easy way on this one, you have to get them out to measure them.
Or you`re lucky you can still read the size on the rear side, but that don`t make much difference.

Inge K.

[TimTyler]

Thanks, Inge.

Duck's valve shim swap instructions:

• Push down valve head at edge with hold-down tool
• Insert spacer to hold valve head in place
• Swap valve shims
• Use hold down tool to remove spacer

Is it possible to remove a shim and then remove the tools, leaving the valve temporarily shim-less (so I can run and buy the necessary new shims)?

[wmax351]

Thanks, Inge.

Duck's valve shim swap instructions:

• Push down valve head at edge with hold-down tool
• Insert spacer to hold valve head in place
• Swap valve shims
• Use hold down tool to remove spacer

Is it possible to remove a shim and then remove the tools, leaving the valve temporarily shim-less (so I can run and buy the necessary new shims)?

You should be fine leaving them out.

[CRASH]

How many miles on your K75?

[TimTyler]

About 90k miles.

I have a service receipt from the previous owner that shows a "check valves" at 70k, but no details regarding results or parts listing for replacement shims.

[Duc750]

In my experience a service receipt saying "check valves normal means the mechanic has walked up to the bike with the fairing on and said "yip, they're there" and walked off again!

[CRASH]

So the next question, are you sure you are checking them correctly? It s pretty easy to make sure the lobes are in the right place on these bikes, and I am not questioning your ability.  Just make sure.  That is pretty tight (especially if they were really checked 20k miles ago).

[frankenduck]

So the next question, are you sure you are checking them correctly? It s pretty easy to make sure the lobes are in the right place on these bikes, and I am not questioning your ability.  Just make sure.  That is pretty tight (especially if they were really checked 20k miles ago).

I had the same thought.  Those seem pretty tight for a K.

The cam lobes should be pointing slightly downward when measuring the exhaust valves - perpendicular to the face of the valve shim.

[TimTyler]

I didn't realize the lobe position was that critical. I had them close to pointing horizontally. Will measure again tomorro when they're pointing exactly opposite the valve.. Thanks for the tip.

[TimTyler]

I just now checked the exhaust valve spacing properly and the results are the same.

I should have tools tomorrow or the next day and I can find out what shims are in there.

[Chaos]

It's not unusual for these bikes to not need much adjustment so it gets neglected. I had 2 tight exhaust valves in the last 80K (189k on bike) I found the most confusing part to be mixing up mm and inches, but that may just be me. I used a good vernier caliper to check the shims. Double and triple check you math before ordering the new shims, and be glad you not doing a K1600!

[frankenduck]

Where are you getting your shims?  South Sound?  If so, call them for availability prior to going up there.  Before I did mine last week I called Ride West and they didn't have a whole lot of variety in stock. (Fortunately I had what I needed on hand.)

Also note that they'll rush orders for an add'l 10%.  Worth it for less costly parts to get you back on the road IMO.

[TimTyler]

I called South Sound today and they told me they don't stock K shims in Parts.

Fortunately they said that if I brought in the old shims they could probably exchange them from the shim box in the Service Dept. :)

I might ask them to measure the old shims too since I bet they have something more accurate than my POS Harbor Freight caliper.

[TimTyler]

Got Ken Lively's shim tools in the maill this morning. Simple tools, simple price, did the job perfectly. Ken is at polepenhollow@yahoo.com Had to find a strong magnet to help suck the shims out of the valve sleeves. Compressed air-can helped on two of the shims.

Took the three shims to South Sound BMW where the GM measured their thickness on their nice digital caliper and traded me for shims from their Service department based on my calculations. The old shims measured 2.52, 2.52, 2.6 so there's still room for years of wear. Measured the new shims at the dealer too.

Installed the new shims and ran the engine for 10 seconds with the cover off. Checked the gaps and all measured roughly 0.25mm which is odd because my math was aiming for 0.30. For example, one valve had a gap of 0.10. The old shim measured 2.6mm so the selected replacement shim is 2.4.   2.60 - (.30 - .10) = 2.40  Oh, well, 2.5 is acceptable.

Sealed up the cover with Yamabond 4, waited an hour, started her up and no leaks. Good times.

Now to balance the throttle bodies....

[kennybobby]

The reduced clearance that you measured was due to thermal expansion from the heat of running the engine.

[Uffda]

On the heels of Tim's post, I'm going thru the same process (1st time for me) but having trouble with #3 valve.  Wonder if Tim, or anyone else, can comment on what might help me along.
95 K75RT, 75,000 miles.  Checking valves today and #1 / #2 are tight (.23mm) and need replacement shims.  #3 is "okay" at .28mm which is good because my question is:
How do you hold #3 open to get the shim out?  I am using the Ken Lively tools and they worked great on 1 and 2.  But #3 is at the end of the camshaft and the forged end does not fit the hold down tool very well.  It seems to be a smaller diameter and slight taper allows the seat to come back up way too much when I release the tension and I can only partially dislodge the shim but not enough room to pull it all the way out.
So, lucky for me that it's only 1 and 2 that need replacement for now but eventually I need to replace the #3 shim.  Do I have to resort to a strong push on a big screwdriver to hold the valve head in place?

[TimTyler]

#3 Was actually the easiest for me to remove, as I recall. I think I used the pry tool on the left edge of the valve and the hold-tool on the right side. I used a couple of magnets (one on top and one on bottom) to free the shim from the seat.

I'd be interested to hear what the more experienced think about replacement shims with your clearances. BMW recommends a 0.25mm gap and the 0.30 suggestion (here in the forum) just allows for extra wear AFAIK. Since you've got it all taken apart I suppose there's no point in stopping now, but I personally would probably not re-shim again until I was < 0.20.

[Rick G]

Just a word of caution here. I always measure the shim thickness with a micrometer because the high wear point on a shim is in from the edge and when using calipers you will measure the thickness of the outer rim where there is no wear and get a correct reading for the shim when it was new. As a result you may get too much clearance or not enough depending wether you measured the shim going in or the one comming out.
Like most of us the shims are wearing out too and if I find shims that are worn I throw them away because if you put them in upside down they can crack and that is disasterous.

[Uffda]

Thanks for the input.  I will recheck the shim thickness with a good micrometer from work tomorrow.  Hope I can find the right shims available when MaxBMW opens for business on Tuesday.  Based upon my initial measurements at home, I think I had a 2.45 amd 2.50 shim in 1 and 2.  Need to drop them down by .05, so I should be able to swap the two and just need to get a 2.40 shim for #1.
By the way, the Check/Adjust Valve worksheet recently posted by Frankenduck was very timely and a huge help keeping my first attempt at Valve check/adjust organized and proper.  The listing of Valve Shim part#s is a great reference and the 4 step instructions are a fine example (unlike my posting here) of succinct communication.

[TimTyler]

... if you put them in upside down they can crack and that is disastrous.

Wait... What?

How can you tell which side is up/down?

The shims I removed from my bike had circular wear on one side from contact with the valves. The replacement shims I got from my dealer were identically plain on both sides.

[Rick G]

If it's a new shim it will have a number on it and that side goes down. If the number is gone then the marks that you mentioned are the indicators and if there are no marks or shiny both sides and are not worn will be ok either side.  A good straight edge will show wear on one side and flat on the other in that case the flat side goes down and if they are shiny both sides and not worn then it dont matter.  You need to be watchful as there are quite a few worn shims around. You can hold them so the light reflects off them at a very shallow angle and that will show up most imperfections like pin holes where the hard face is starting to come away and circular patterns which will show hollowing (chuck them out) sometimes just running your finger nail across them will pick up unevenness.  More than anything a good visual inspection and a straight edge will show most potential problems.

[GasStation]

Got Ken Lively's shim tools in the maill this morning. Simple tools, simple price, did the job perfectly. Ken is at polepenhollow@yahoo.com Had to find a strong magnet to help suck the shims out of the valve sleeves. Compressed air-can helped on two of the shims...

Before ordering those valve adjusting tools myself, I wanted to confirm with you that Ken Lively's tool duplicates were in fact just as good as the BMW selling for $86 and worth the $58 savings? I don' t mind saving unless the product is not worth the coin.