HPN - I just want one

[Phreaky Phil]

Originally Posted by Deadly99

Oh man....beautiful...

There'd be enough fuel on that to do the whole TCAT without filling up !

[Deadly99]

Originally Posted by Phreaky Phil

There'd be enough fuel on that to do the whole TCAT without filling up !

I've been unsuccessfully hunting for that rear tank and the hpn rally fairing for a project bike...anyone have a source ?

[Clay Spinner]

Originally Posted by Deadly99

I've been unsuccessfully hunting for that rear tank and the hpn rally fairing for a project bike...anyone have a source ?

Mate I've been looking for a year... no luck yet!

[hardwaregrrl]

Originally Posted by Deadly99

I've been unsuccessfully hunting for that rear tank and the hpn rally fairing for a project bike...anyone have a source ?

Make one! You should see if Prutser would make you one. HIs is a work of art!

[Dakar83]

Originally Posted by Deadly99

I've been unsuccessfully hunting for that rear tank and the hpn rally fairing for a project bike...anyone have a source ?

Have you contacted HPN? My tank, tank tool bag and under seat water container came from them.
I think they also supply the fairing but if not I have seen them come up on German eBay a few times.

[Dakar83]

Went for a ride on the R80G/S today, been wanting to give it a good run to blow out the cobwebs. Weather this morning was a blue skies and 27 degrees celsius, just perfect for riding, made better by no weekend traffic !

Headed up to Toodyay on the bitumen, just taking it easy and enjoying the quiet road. There were about a dozen bikes in town, all the riders grinning at their good fortune getting away for a Friday morning ride and catching this great weather in between the Heat waves!

On the way back I couldn't resist taking the old scenic road north of Toodyay.





The bitumen quickly gives way to a nice gravel road through some hilly pasture and farmland before moving into native forest.
The road follows the rail line much of the way





I have not taken this bike on loose gravel before so went slowly. I was rewarded with a surefooted ride the G/S behaved impeccably until some corrugations had me thinking the suspension might be set a bit hard (the bouncing unlocked the seat! but no drama, just pulled over and locked it back in).

Too soon it was back onto the bitumen and head for home back in time for lunch. Though I did see a number of side roads that really are asking to be explored. I think I'll have to borrow my son's GoPro and head back up there on the HPM. ;-)

Now for some forum participation!
The G/S has been throwing some oil on the rear wheel, at one point I thought it was just from the top filler plug. but now I am thinking it may be more ominous. Only the right/drive side of the wheel gets the spray, as you can now see thanks to the dust from this mornings ride.







There was no oil residue around or under the filler plug, checked the drain plug which had a new crush washer at last service. Looks to me like thats where it's coming from and I was able to nip it up another 1/8 of turn, so I hope that'l sort it. Any other views?

[Rucksta]

Replace the "O" rings on the shaft that actuates the rear brake.

[hardwaregrrl]

Originally Posted by Rucksta

Replace the "O" rings on the shaft that actuates the rear brake.

+1. Make sure they're genuine BMW parts.

[rediRrakaD]

Originally Posted by hardwaregrrl

+1. Make sure they're genuine BMW parts.

Or have a friend machine a second groove and add another 'o' ring .
S.

[Ras Thurlo]

btw- great numberplate

Originally Posted by Dakar83

[Dakar83]

Thanks for the advice about the o-rings on the rear drum pivot arm. I didn't realize this tracked through the final drive oil reservoir.
When I removed the pivot arm about 15-20mls of final drive oil leaked out of the pivot arm hole, is that normal? Bike was level.

The next surprise was the absence of a washer from the inside end of the pivot arm. This washer appears in the BMW schematic and the Clymer manual. However it appears as though this unit is designed without the washer as the surfaces are a good flush fit and the splines on the outside end of the pivot arm would not fully protrude if a washer was added ?? The bike is Oct 1980 build date.

Anyway I was able to pickup some o-rings from my local BMW dealer 32c each, can't complain!

There are several grooves in the pivot arm but only 3 are machined with a square profile (good information from Snowbums blog)
2 are on the inside end which did not appear to leak, one on the outside end which seems to be the culprit. I have only changed the outer o-ring. Now I'm thinking I should have done all 3!

Anyway here are some pictures
First the inside of the final drive. Dry except for slight signs of oil around the bolt above the pivot arm? It was tight.




Here is the washer-less pivot arm with 3 o-rings




Now I'll just have to get out for another good run to see if the problem has been resolved.

[Dakar83]

Originally Posted by Ras Thurlo

btw- great numberplate

Thanks Ras

[Rucksta]

Your's look like it has the usual mod for the age with at addition of an extra groove on the brake side.
It seems only the "O" ring closest to the brake shoe wears significantly.
I change all three so I can do a swap around in the field if it starts leaking on a trip.

Later models - post '83- have a brass tube running through the FD and were fitted with four "O" rings.

My '82 came with a washer and a felt pad on the brake side and a wear indicator on the lever side - both long since gone.

The leakage around the bolt is typical of a broken gasket.
Std assembly uses a paper gasket; common practice is to use a sealant instead of a gasket.
The variation in thickness of the gasket must be accounted for in the stack of big shims that determines preload on the big bearing.

You may be able to open the housing throw some some sealing goo on the surface and reseal without having to reshim.
Alternately removing the bolt and sealing with silastic may get you through to the next FD service or you may learn to live with the leakage

The hole above the bolt is an inbuilt puller for the inner housing - look for a matching hole at 180 deg.
Moderate heat - propane torch - will ease the disassembly process.

350ml is the specified oil volume.

[One Less Harley]

mine leaked at the brake pivot, you might make sure it's not loose as mine was. I pulled it out and put permatex #2 on the pin. It's been dry every since.

[Dakar83]

Originally Posted by Rucksta

Your's look like it has the usual mod for the age with at addition of an extra groove on the brake side.
It seems only the "O" ring closest to the brake shoe wears significantly.
I change all three so I can do a swap around in the field if it starts leaking on a trip.

Later models - post '83- have a brass tube running through the FD and were fitted with four "O" rings.

My '82 came with a washer and a felt pad on the brake side and a wear indicator on the lever side - both long since gone.

The leakage around the bolt is typical of a broken gasket.
Std assembly uses a paper gasket; common practice is to use a sealant instead of a gasket.
The variation in thickness of the gasket must be accounted for in the stack of big shims that determines preload on the big bearing.

You may be able to open the housing throw some some sealing goo on the surface and reseal without having to reshim.
Alternately removing the bolt and sealing with silastic may get you through to the next FD service or you may learn to live with the leakage

The hole above the bolt is an inbuilt puller for the inner housing - look for a matching hole at 180 deg.
Moderate heat - propane torch - will ease the disassembly process.

350ml is the specified oil volume.

Thanks Ruksta that's really usefull information and it gives me a progressive plan of action.