K11 Owners Group

Sidmariner

While chasing down a nagging leak from the valve cover I discovered that the lower right cover bolt has stripped the hole in the top of the camshaft bearing cap. The bolt is fine but the hole is toast.

Should I: a. bore out the hole and try to fit a heli-coil;
b. fill the whole with metal epoxy and tap a new thread;
c. tap the hole to oversize and try to replace the bolt with a larger one; or,
d. just buy another bearing cap?

If d is the answer, apart from the Boneyard, where would you suggest I source another cap?
_________________
Thunderbird 1: '93 K1100LT
Thunderbird 2: '86 K100RS
Thunderbird 3: '02 R1150RT
Thunderbird 4: '77 R100/7
Thunderbird 5: '86 K75C

Flying Duck · Posted: Thu Jul 10, 2008 4:11 pm Post subject:

Place an ad on IBMWR to see if anyone has a K100RS4V or K1100 head they can pull one off of. Also ask here at K11OG.
_________________
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

chopper_harris · Posted: Thu Jul 10, 2008 5:05 pm Post subject:

Helicoil kit - the best $50 you will ever spend Wink

Done correctly, they are as strong as the original thread.

The bearing caps are torqued to 9Nm (7 lb/ft), so there is no significant load on the repair.
On such an easy location, fitting the heli will be a doddle - I have fitted them upside down lying on my back in the rain, and they just work Very Happy

A decent second hand head will cost you at least $200, and will likely need reshimming.
This will be $50 ($2 if you can find someone to loan you a heli-driver)
_________________
C1 200 (2001)
R100 RS (1990)
NSU Quickly N (1964)
Honda 400/4 F1 (1977)
MotoGuzzi 1000C (1978)
Suzuki TL 1000 R (1999)
Kawasaki KLV1000 (2005)
K12R Sport (2007) - Wifeys

Flying Duck · Posted: Thu Jul 10, 2008 5:08 pm Post subject:

CheapJapCopy · Posted: Thu Jul 10, 2008 5:13 pm Post subject:

Or he could just buy a head, get the bits he wants and send it to me Wink

_________________
1992 K1100RS - Red and gold.

chopper_harris · Posted: Thu Jul 10, 2008 5:33 pm Post subject:

ah - I didn't read the post thoroughly enough Embarassed

Still, now you can practice your heli-coil skills whilst stood comfortably at your workbench, rather than on hands and knees Wink

_________________
C1 200 (2001)
R100 RS (1990)
NSU Quickly N (1964)
Honda 400/4 F1 (1977)
MotoGuzzi 1000C (1978)
Suzuki TL 1000 R (1999)
Kawasaki KLV1000 (2005)
K12R Sport (2007) - Wifeys

gpzoduibh · Posted: Fri Jul 11, 2008 6:29 am Post subject:

As far as I know the cam bearings are line bored if you f*** up the cap the head is junk ??
Hope that doesnt depress you I have helicoiled three of the caps in my head and it worked fine.
Regards
Bill Black
_________________
1995 Grinnall Scorpion III(1990 K100 16v motor)
2010 KTM 450 EXC
Moto Guzzi V50 powered hovercraft !
1989 K100RS (8V) special edition
1974 Yamaha DT360
1972 Sanglas 400 T
1980 Yamaha XS110-Watsonian Palma sidecar
1966 Bridgestone 175 dualtwin
1980 BMW R100RS
1979 Bultaco sherpa T 350
1979 Yamaha DT175MX
1990 Honda XR250R

chopper_harris · Posted: Fri Jul 11, 2008 10:22 am Post subject:

The camshaft caps are not listed on the fiche sites, so you are probably correct Crying or Very sad

_________________
C1 200 (2001)
R100 RS (1990)
NSU Quickly N (1964)
Honda 400/4 F1 (1977)
MotoGuzzi 1000C (1978)
Suzuki TL 1000 R (1999)
Kawasaki KLV1000 (2005)
K12R Sport (2007) - Wifeys

hockeyshifter · Posted: Sun Jul 13, 2008 6:21 pm Post subject:

do the heli coil thingyyy.. i have used it in the past on a bike and on car that used that really soft / potted metal. the big thing with heli coil is the minimal amount of material that you remove and replace with the coil.. would i suggest this for use in a head replacement no but in minor load bearing this stuff is the best.. as for the rest a direct replacement will give you peace of mind the other 2 bore out and stuff with filler should only be used a tempory fix.
_________________
fix the problem not the blame ; fix what is messed up ; NO one is to blame.

Technician · Posted: Mon Jul 14, 2008 12:48 pm Post subject:

Your other option is to use a Time-Sert made by Wurth. These are similar in principle to a heli-coil but instead of a spring type coil thread they utalise a hardened steel threaded insert which has the correct thread on the inside and a different one on the outside. They are more permanent but also more expensive.
_________________
Fat Ba***d with a K1100LTse
Squire D18 trailer
Garmin Zumo 660
"Run it round the block to see if the wheels fall off!!!!"

Phil Marvin · Posted: Mon Jul 14, 2008 6:43 pm Post subject:

Hi, Sidmariner,
You don't want to hear this, but... the bearing caps are not available from BMW. They are line bored, so if one is upgefücht, and if you cannot Helicoil it, it is new head time. Helicoil or Timeserts should work, but be careful and do it correctly. I don't use a torque wrench with mine. I get them "snug" and leave them. If, later, I find some oil, I fine the one(s) which are loose and snug them up again. Good Luck!
Ride Safe,
_________________
Ride Safe,
Phil Marvin in El Paso, TX
'94 K75A/3
'95 K75RTP

Sidmariner · Posted: Tue Jul 15, 2008 1:57 pm Post subject:

Thanks everyone.

In the end, I mixed up a tiny batch of JB Weld and coated the inside of the stripped hole. When it was just about set up (hardened but not hard) I ran the bolt into the hole and carefully cut a new thread. I then backed out the bolt and let the JB Weld harden completely.

Touch wood, but it holds beautifully.
_________________
Thunderbird 1: '93 K1100LT
Thunderbird 2: '86 K100RS
Thunderbird 3: '02 R1150RT
Thunderbird 4: '77 R100/7
Thunderbird 5: '86 K75C

tmarshall57 · Posted: Wed Jul 16, 2008 12:16 pm Post subject:

I fixed a damaged woodruff key slot on an outboard motor crankshaft (where the generator coils bolt onto the crankshaft) using JB Weld and it worked for the life of the motor. Should be fine.
_________________
K1100RS Special Edition 1997
Arctic Silver/Black