k100 blown head gasket

[Barrieb]

Hello,

I'm new to the joys of brick ownership (worked on few boxers I the past) and about to do the head gasket on a 1986 k100

Got couple of questions, grateful for any support:

1. The bike runs fine, but I'm seeing oil in the water, have drained oil and that is not showing much sign of water, but coolant defiantly has enough oil to be worried.  The bike has 66k miles on the clock and does not show any other signs of excessive wear.  Before I go taking off the head are there any other likely areas to have failed other than the head gasket?


2. I'm Not happy with the Haynes manual instructions for reinstalling the camshafts, the positions are very vague and lacking in diagrams compared to other DOHC engines in Haynes manuals.  Has this been covered in a previous post or does anyone have a link to a decent description/diagram or anything?

Thanks

"Just working to get another brick back on the road where it belongs"

[rbm]

Before I go taking off the head are there any other likely areas to have failed other than the head gasket?

Yes, you probably need to replace the seal in the water / oil pump because it is leaking.  Much cheaper and easier than a head gasket replacement.  The Bricks are bulletproof and rarely does a head gasket blow.

...  does anyone have a link to a decent description/diagram or anything?

OEM service manual is available online.

[koapono]

i'd do a compression check before i started tearing her down.
pull plugs, do any of them look "steam cleaned"?
likely water-pump seals.

[Barrieb]

Thanks Guys,

You were spot on, I've taken off the water/oil pump and the seal are obliterated!
Problem now is the pump drive shaft is badly corroded where the mechanical seal was positioned and where the mechanical seal sits in the pump body looks not to clever!

If I can clean up where the mechanical seal sits enough, can the pump drive shaft with its gear be replaced or am I looking at trying to get a complete replacement?

Thanks again

Barrie

[drut]

Motorworks or Moto-bins listings worth a look

http://www.motorworks.co.uk/vlive/Shop/Parts.php?T=5&NU=15&M=40&Ct=GA&SbCt=BA_15_40_GA_75

[rbm]

Follow this tip to use superglue to smooth the pits and prepare the shaft for the replacement seal.

[Barrieb]

Thanks Robert,

I think my gear pump shaft is a bit too far gone, I'm lucky enough to have a load of spares including a complete engine.

I have had a look at the pump on the spare engine and this looks good with no sign of oil leakage in the water, also it has the bolt and light weight impeller.

Is it a reasonable idea to try this pump straight on my bike ( following the great guidance on this site for pump refitting) ?

Thanks

Barrie

[F14CRAZY]

When my water pump seal went bad I tried replacing the seal won a pitted shaft twice. I gave up and installed a used pump from eBay. I have like 10k miles on it so far and no leaks.

So yeah, I don't see any harm in trying another pump

[drut]

"Is it a reasonable idea to try this pump straight on my bike ( following the great guidance on this site for pump refitting) ?"

Sounds to me like a better proposition than repairing a pitted shaft

[rbm]

Defenitely give it a go.  It's the fastest repair.  The pumps from K100, K75 and K1100 are all compatible AFAIK.

[F14CRAZY]

Oh yeah...K1200 pumps are also compatible but you would have to get the little drive gear that goes on the front of the block as the teeth are different. I can't remember at the moment but I think you also need the front cover. I have a K1200 pump on my bike.

Note: youd want a flying brick K1200 pump, not the later, transverse K1200 pump (not the same)

[Barrieb]

Thanks guys,

I'll let you know how I get on