K11 Owners Group

CR_Bricker · Brick Rider Joined: 06 Nov 2016 Posts: 25

Today I finally got round to doing a valve clearance check on my 1991 K100RS 16V. I have owned the bike for a year and it has about 125,000 miles on it, I say about because the speedo didn't work when i got the bike.

I had put off doing the check because

1. Chris Harris says it isn't necessary because the valves may get loose, which is ok, but they don't get tight.

2. I started this project as a total novice mechanic and although I have done lots to the bike opening up the engine did fill me with trepidation.

Anyway the good news is the process went very smoothly and is easy to do.

The bad news is it seems CH is wrong.

Of my 8 intake valves 6 were tight, four of those would take a 0.13mm but not a 0.15mm which is the minimum and the other would take a 0.10mm but not a 0.13mm. The other was on the tight end of spec, t wold take 0.15mm not 0.18mm

The exhaust valves were not much better.

I had four valves in spec at 0.25mm but wouldn't take 0.28mm and four tight ones that would take 0.23mm but not 0.25mm which is the minimum.

Not a single valve was loose.

That strikes me as odd given what CH said.

Anyway has anyone tried shimming a 16V? I hear it isn't easy.

_________________
1991 K100RS with K1100 RS fairing
Costa Rica

Flying Duck · Posted: Wed May 31, 2017 4:40 pm Post subject:

The head of the valve bucket is smooth so there's no way to shim like a 2V K.
_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE

CR_Bricker · Brick Rider Joined: 06 Nov 2016 Posts: 25

Well it is possible to adjust the valve clearances though I assume? Is it something a guy like me can do is it a BMW dealer only kind of job?
_________________
1991 K100RS with K1100 RS fairing
Costa Rica

Flying Duck · Posted: Wed May 31, 2017 5:31 pm Post subject:

You need to get new valve "buckets" of the correct thickness to "adjust" the valves.

http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/4valves/4valves.htm
_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE

SugarHillCTD · Posted: Wed May 31, 2017 5:35 pm Post subject:

I have a '92 K100RS 16v.

A few years ago I did a valve check and several valves were borderline.

18 months ago I did a check then had to change a few shims.

It really isn't too hard to do.

By the way, valves do tend to get too TIGHT, not too loose (no matter what the madman Harris says- and yes I have met him several times).

What happens over millions of valve cycles is that the valve seats can VERY slightly receed into the cylinder head but the valves themselves do a reverse mushroom (the stem elongates from the valve head while the valve head slowly looks like an umbrella that the wind catches). The combination action will, over a long period, lengthen the valve length, thus tighten valve clearance.

First you need to establish the existing clearances on all the ones that are out of spec. Write it down on a schematic.

Next run a zip tie through one of the cam chain sprocket holes and around the chain for both the intake and exhaust to keep from losing the timing. Slightly loosen the bolt holding the cam chain sprockets to the cams. Keep them finger tight.

Now mark its position then loosen and remove the HES and the cam chain cover. At this point I also zip tie together the first two upper and lower links coming off the cam chain drive to keep it from jumping a tooth. Remove the cam chain tensioner.

Now you can remove the bolts holding the cam chain sprockets from the cams, undo the 2 nuts holding the black chain runner and pull the sprockets off the cams- you did zip tie them to the chain, right?. BTW, they only go back in the correct position- they are "keyed".

You can now undo the other 18 nuts holding the cams down. Mark each of the cam hold downs so they go back in the same place and what is up with an arrow. These should go back in the exact same position.

CAUTION- when you remove the exhaust cam (the lower one), the shim cups will try to fall out- maybe all 8 of them. So go slowly pulling the cam out from one end first. Try to catch and organize them one at a time.

Also while some documents do not recommend swapping shims from one valve to another, $$$ suggests otherwise. I swapped some and the sky didn't fall.

Now send away for any shims you need and then reassemble.

Ask if you have any questions, OK?

John

BTW, this is from memory. Others may add their input. But if you have any doubts about procedures ASK! Smile

_________________
John & Cathy

'92 K100RS4V Pearl White SOLD
'04 K1200GT
IBA Several-SS1k, BBG, 50CC NYC to S.F.

N41EF · Posted: Wed May 31, 2017 5:55 pm Post subject:

Check eBay once you know what buckets you need. I have a few NIB shims from eBay, post what you need any maybe someone has a spare.
_________________
2014 R1200RT Water Cooled
2001 R1100S Light
1993 K1100LT. Nissan Ice Blue.(Gone)

CR_Bricker · Brick Rider Joined: 06 Nov 2016 Posts: 25

OK that sounds scary but doable.

So I need to take out the old buckets first to know what size new ones I need?

ie if the valve is currently at 0.13mm and I need to get it to 0.20mm I need to measure the depth of the existing bucket and then buy one that is 0.05mm less?
_________________
1991 K100RS with K1100 RS fairing
Costa Rica

N41EF · Posted: Wed May 31, 2017 7:51 pm Post subject:

Yep, and Duck above posted a link to the part numbers and the thickness off all of the original buckets. From Johns discussion, I'd round down to the next available bucket that puts your clearance in the middle of the spec.
_________________
2014 R1200RT Water Cooled
2001 R1100S Light
1993 K1100LT. Nissan Ice Blue.(Gone)