Ontic's 1981 R80G/S build-up thread

The time has come,
here's the thread I've been meaning to start for a long time, the progress to date, the plans to come, and the questions arising...

It started with a walk in the bush. I was just beginning a renovation on a friends property in a forrested zone by the river not too far from my city. I'd spent the day cutting up a big old rusted watertank and piling it into a skip.
Now that the watertank was gone, and I got thirsty, I had to walk next door to fill up a large water cooler from their rainwater tank...
so,
what do I find but this,





A damsel in distress!

I'd wanted a R80G/S for quite a while. In fact it was the bike I wanted before I settled on my R90/6 (because G/S's were too hard to find and too expensive!)
This old girl was looking very neglected. Sitting out here in the weather when there was a perfectly good shed not far away where it could have sat under shelter.
The little details all pointed to general neglect and lack of care....



Anyway, to cut a very long drawn out story very short: I put the feelers out, found out the owner was wanting to sell, but hadn't advertised yet, and we worked out a price. I bought it and rode it home 8-9 months ago.

Lets see,
condition:
Speedo, cactus.
Battery virtually dead.
Starts easily and runs very well.
Shifter linkage is loose from a destroyed bush, but still it shifts OK and gearbox feels fine.
Biggest scare is a bit of knocking coming from the front of the engine once it has warmed up and settles into a low idle... sounds like a loose timing chain.... I HOPE it is a loose timing chain!
There is all sorts of rust and corrosion and damage from sitting out in the weather and being treated hard.
thats a start at least...

It has rusty stainless steel headers- later found out to be home made/custom, and a staintune exhaust, later found out to be adapted from another bike.

The rear shock was leaking and on the test rides and the ride home just bounced along hopelessly. Turns out it is an old Koni and after pulling it apart it is most likely un-repairable.




So:
I had bought this thing for a pretty good price, but at a time I really should not have bought another bike, so it had to just sit there for while until I figured out my plans and gather funds to start.

I started pulling things apart and putting them back together.

Rear shock: as mentioned, cactus.
Speedo: pulled it apart- not pretty. Nothing worked, everything rusted, seized and/or broken. During my efforts to fix it a fellow boxerworks member donates a R65 speedo and I manage to cobble together a working G/S speedo between the two. This is a long story cut short. Here's the photos






one of many rusted, swollen and seized parts: this one repaired by electrolysis rust removal





silver gear on top right was spinning, and the shaft running through the white gears on the bottom for the trip meter was completely swollen and siezed: again, electrolysis and a lot of patience and persistance repaired this part.



so, while the speedo hung out in parts in a box I gradually fiddled with other things...
swapped on some appropriate valve covers..
earlly stages of cleaning things up. Heavily corroded.
Uncleaned side,


'Cleaned' side


as you can see, a hell of a lot more work to do yet.


anyway,
eventually I fixed my speedo.
it now works and looks nice too.


There was a lot of work in this, but I won't go into it unless anyone is interested.
One may notice I have reset the odometer. Due to the non-matching frame/engine numbers on my bike I was under the impression that the engine had been swapped at some point- and combined with a speedo/odo that had not worked in a while I didn't put too much importance on the numbers that were showing... since then I have learned that the numbers of this era of bmw may have come from the factory not matching??
Anyway, I know the insides of this thing like the back of my hand, so I may re-set the thing to the numbers I got it with... we'll see.
more on that later maybe.

Next post coming up:

So,
what's the plan???

Need a new rear shock... local options were expensive, even the cheap ones:eek1 So, I started preparing for a painful hit to the wallet and looked into other options than buying in Oz.

Front forks- not too inspiring.
Front end swap being dreamed about and plotted.
First I was going to do a GS 40mm Marzocchi swap- but now I am headed towards a 50mm WP extreme front end.

Other than that a general 'rebuild', not resto, I wanted to build this bike into a competant tour-anywhere dual purpose beasty that could handle dirt a LOT better than my R90 can. Sometimes I get a bit OCD about things, other times I get a bit 'whatever' and 'she'll be right'... you'll be seing a fair bit of both over this thread.

I've ummed and ahh'd about extending the swing arm and raising rear and front suspension travel and ride height and am still undecided. I'll be putting the WP50's in at a lowered (to stock G/S) height to begin with and deal with that issue at a later date.
The frame will be stripped and painted or powdercoated, still not decided which.
Also not decided whether I will do any frame re-inforcements.

In the mean time, between planning and replanning I just pottered along doing what I could.
My nasty home/made headers were begging for a bit of love. These things were stainless but heavily corroded and had dints and grooves and imperfections all over them from the less than ideal pipe bending process they were made in.
Here is some of the OCD stuff...
starting work on one on the right


a bit more detail on the grooves and stuff,


fast forward through angle grinders with flap discs and many many many hours of sanding, polishing, re-sanding, re-polishing, ad-nauseum... we get this



Yeah, it's a G/S and will be treated rough, but I wanted to start from scratch with a good finish and let the patina develop from then on... and I was way sick of looking at my horible rusted chromed, repaired and re-welded headers on my 90/6. (and I had nothing else to do but read on the net and troll german ebay and wait wait wait...)

bringing it up to present:
A little while ago I settled on an Ohlins BM317 rear shock as the thing to buy, and all that remained was to find an international seller who would send it to me and pony up with the dollars.
For a nice change, our exchange rate was BRILLIANT. I paid for this at about Aus$1=US$1.09.
Arrived a few days ago.
Thanks Dan


Next. I wanted a big tank. Not just because I want a long range at times, but also because I've had a lot of troubles on my 90/6 with load distribution when hauling all my camping and traveling gear- the back gets too heavy and the front too light- not so bad on the road but sometimes very bad on the dirt. I want more weight up front and a larger tank fits into this...
so,
lots of trolling of german ebay.
I found a BIG tank that took my fancy, an alloy one, that I hadn't heard of before.
Anyway, I won the bidding on a Sauer 45 Liter alloy tank made specifically for the G/S...



This morning a BIG package arrived....

I like where this one's heading

Here is a few ebay photos of the tank






damage




anyway,
I'd found some other images on a german forum showing this same tank in a different guise: things looked promising. I really like it with the GS single seat. I was planning for a G/SPD single seat, but may go down the route of trying to fit a GS single seat to my G/S subframe, or look into swapping to a GS subframe and seat...
not sure yet,
discussion of the possibilities and consequences of either option is welcome




I also found this image from Sauer's own site

after unwrapping the HUGE box this tank came it I was a little suprised.
Yes, it was big.
But, it also STANK.
Don't let anyone tell you you can't get a used tank sent by airmail. Don't let anyone tell you you can't get a used tank that stinks of gasoline and is coated in grease and grime and stinking oil posted by airmail:eek1:eek1
The seller said it didn't smell at all and he would clean it out with hot soapy water anyway.
I opened it in the living room- my partner could smell it in the shower in the bathroom!
Either way it made it through customs so I think I got pretty lucky there.



straight away, after giving it a thorough clean and degrease, and peeling off the stickers, I set about starting to 'improve' the major dent.
I took a nice size comparison photo between the original G/S tank and the new Sauer tank, but I seem to have lost it,
I'll take another one tomorrow.

Here is the dent


hard to see well.

here is the approach,
old hammer head + length of steel + welder


hacksaw (left my angle grinder with cut-off disc at mates place)


give it a blast on the grinder, freshly decorated with a sticker from the Sauer tank (to remind me to wear eye protection)


and we are ready to go


This 'tool' was able to reach straight through the fuel hole in the top to the dent and with a bit of beating and tweaking later, I don't seem to have done any permanent damage and in fact I have actually improved things to the point where I will be happy to fair over the remains ready for the repaint.
Again, it is hard to actually see what is going on here.



now some photos on the bike,

all these crappy photos are from my old mobile phone camera, so apologies for that. The colour of this tank is interesting, and doesn't travel well digitally. It is a dark greyish sort of invisible purple colour, and then on the all the corners there are dark greyish sort of invisible green accents:huh
I don't mind it actually, it is quite unique and distinctive, but it will go.

anyway,
here she is,






fitment stuff
from above at full steering lock


from below at same


here's some details of the tank,
I don't know what these welded on strapped mounting-like points are for. Ideas?


heres the underside







personally, I LIKE this tank, it fits me well, and IMHO it works nicely with the classic airhead lines.




that's it for the moment.
there are a few points I'd like advice on which I will take up later,
cheers,

wow, I like the last photo with the new tank - Sauer really did a great job in keeping the bike's lines flowing into the new contours. I actually think the old paint looks great - old patina against the new polished headers!

do you think the aluminum tank might look good ... polished??

--S

Cheers,
yeah I agree, for a really big tank, which it is, I think the bikes lines flow incredibly well. I have nothing at all against the big acerbis or HPN tanks, and this is purely a personal thing, but the lines of both of them don't do much for me. This tank on the other hand...
each to their own.
I can't get too precious with the tank... being alloy, and being this big- any tip-over is likely to add some fresh dents pretty easily.

I do like this old paint, and I love a bit of patina, but it is just a bit too rough for me to keep it like it is I think- especially once this bike is finished. It is pretty safe to assume that this is not 'original paint' I believe, as I have found a fair few faired over small dings in the tank, over which this paint has been done. So I don't feel like I need to be worried about preserving the originality of the tank or anything.
Also, while it looks fine in some spots, and would have looked fantastic when freshly done, this paint is probably not the best quality or is just a bit old and worn now. Its a bit soft, scratches, and flakes off easily on a few bits that don't seem to have been primed properly.
I am actually looking forward to doing a nice job on the tank- but really don't know what colour to go for. SUGGESTIONS WELCOME.
One thing is for sure- though I like the odd and unique colour it is now- I NEVER would have chosen it out of thin air!

oh you evil bastid! I really don't need that sort of encouragement. Polishing really brings out my OCD tendencies. I spent quite a while waiting for this tank to arrive and have spent a lot of time thinking about polishing it, or at least part of it. The cut outs for the knees was what I was mainly thinking of polishing, and this could probably be done quite easily.
However, given the amount of skimmed fairing over some the tank and the amount of very small dings that have been faired in, it would be quite a bit of work to polish the whole tank nicely- and virtually impossible to do perfectly as the baffling inside the tank severly limit the degree to which dents can be repaired without cutting into the tank.

As it is, with a good sand, an etch prime and fair it should paint up beautifully.
Originally I was planning on a black themed bike. Though with a tank this big I am worried that a black tank won't look so great... not sure how to explain it, but I am thinking for this size of tank, white or coloured might look a bit better... black might just be a bit blimpish.. dunno, we'll see. Those are the fun bits.

Probably for a tank bag. If I wanted to put tankbag mounting points on my tank that's probably right where I'd put them.

That's a great looking tank. I don't think I've ever seen one of those.

That's a good looking tank. The tank bag mounts will come in handy if you do some serious traveling.

Good job on fixing the speedo. Oughta last at least 6 months.

Lookin' forward to this one!

Thanks for the comments and interest,

Mounting points on the tank for a tank bag? Of course- that makes sense. I like it.

Now someone can tell me what this little home-made welded, grinded and drilled doodad is that was cable tied to the tank. The seller hasn't replied to my email about it.

Hey you! 6 months? Is that all you give me
The failure in my speedo (or the many many failures) was caused by water ingress and rust. I guess that is to be expected when the trip meter button gets broken off, the hole never gets patched, and the bike lives outside in the rain
I'm hoping for a fair bit longer than 6 months of use, but we'll see.
I am not sure what I will be doing with the headlight. I would like a larger and brighter light and am considering a range of small fairings as well. I might try to make up or mod something to suit.


just for giggles, here's the comparison between the new and the old tanks




now, for a question.
I'd like to try to use a GS single seat (like the one pictured above on the bike with the white Sauer tank).
I realise the G/S and GS subframes are different. Has anyone tried to mod/fit a GS single seat to a G/S subframe?
Other than that, if I go for a GS subframe (which also would allow me to get the GS rear rack that I prefer) does that mean my side covers no longer fit?
I do like the longer GS subframe and the rear rack as it would work better for the way I carry gear. I'll be putting on some pannier frames, probably for hard bags of some sort. I have a set of pannier frames already that were meant to fit a G/S. They don't. and I am pretty sure they are intended for a GS. I could take them back to my parts guy for credit or cash, or just consider myself part way towards the GS subframe...

GS subframe is heavier though isn't it...

anyway, gotta run,
Cheers,

the side covers aren't well-mounted and they fall off when you ride it hard offroad. You'll need to come up with a better mounting solution there anyways so I wouldn't let it keep you from going with the GS sub-frame. The GS sub-frame is about 7 pounds heavier iirc. Airhead Wrangler's thread has the numbers.

Those speedos aren't known for being very durable. I'm glad you didn't spend hundreds to get it fixed only to have it break again. I've heard One Less Harley's horror stories about the trouble he had out of his even after a rebuild.

You lucked up getting those headers. They look to be made like the Staintune system and it's much easier to take off and put on that the stock system. I HATE that stock system. Take good care of those pipes!

I'm really liking the looks of that Sauer tank.

I tried to install a R100GS subframe on my wife's R80ST a couple years ago. She wanted a solo seat/rack set up similair to my R100GS after i tossed her bike off a small cliff.
Because the paralever swing arm is several inches longer than the monolever, the inside front edge of the fender hits the front of the rear wheel. I ended up using a UFO aftermarket fender and had to cut it up and make up an inner fender to clear.





Even then, the wheel would bottom against the subframe with a big bump, but that problem might have been fixed by installing a longer shock, ie GS.
The other issue is that the longer subframe moves the saddlebags back, the centers are now behind the rear axle. With a load, the front end was light and made for sketchy handling at speed.
Your stock right hand side cover will need to be replaced by a R100GS cover, shape and mounting is different.
I ended up returning to a stock subframe to resolve most of these issues.

More pics here

well, we sure dont need to pester you for pics

The whole exhaust system is interesting. The headers looked very home made- well, home made by someone who knew what they were doing but was dealing with non-professional tools or something- there were grooves and marks from the pipe bending and all sorts of tooling marks- after the bending up of the pipes it looks like they were just left at that- no polishing to finish it off.
Between the headers and the muffler is one big Y piece. After the headers it is stainless steel, until it gets to the junction of the Y, and from then on to the muffler it is MILD STEEL.
I didn't notice the mild steel when I bought it, everything was so rusted I couldn't tell the difference.
The whole lot went into the electrolysis bath and then got cleaned up.
Now I have painted the mild steel section after the Y junction with black header paint. It looks OK, pics to follow one day.

The actual muffler is a right hand (ie wrong side) muffler from a TRX 850 (it is stamped into the mounting bracket).


Anyway, the whole mess seems to work OK.
I like the headers now- they are quite unique, and I appreciate the work someone put into this exhaust system.

Thanks for that,
sounds like a bit of hassle. I think I will stick with the G/S subframe.
After experimenting with hauling a lot of gear in panniers and a rear bag on my 90/6 I am quite convinced of the need to keep the weight forward of the rear axle- so that was a great point you made for me.
I am still interested if one could try to fit GS single seat (and rear luggage rack) to the G/S frame... I imagine with a bit of work it should be possible?

Yeah, ahh.. sorry I've been a bit pent up and this has been the catch up page.
I can't wait to get to page two. The computer I am using is having serious trouble trying to load this one.

Didn't try. There is a G/S solo seat/rack available, I believe from Germany.
Of course anything is possible with a welder, torch, and some time.
Someone else on this forum used a R100GS subframe on their bike, they may have some more insight than me. That was just my experiance.

You can get into your settings for ADVrider and specify how many posts youd like per page. I have mine set for ten, so its kind of easy to estimate how big a thread is, based on some screwy decimal system
That might help you image load issues. Set yours for only a few posts per page to make it faster.

that was unrelated to bikes, but fixing these R80's are like an odyssey. Only you usually end up better than Odysseus

Hey Norton73,
cheers, yeah, I will look into it more. But your reminder of the longer subframe potentially putting the luggage weight further back is a bit of a disincentive to me, let alone some of the other hassles. Load balance is a big issue for me.
I have looked through the options of G/SPD single seats from Siebenrock and other places, and was going to go with that option- however, I really think this tank suits the GS single seat. I've tried my (police?) solo denfeld seat from my 90/6 (which is very similar to a G/S single seat) on my G/S with this Sauer tank and it just doesn't 'work' as well as the images I posted before of the white tank.
While on their own I probably prefer the look of the G/S single seats, the GS single seat actually looks a bit more comfortable and is probably quite practical.
Anyway, I am happy to do a bit of modding and fabbing to get the thing to work if that is what I have to do. Ideally I'll be buying used and cheaper, so in the end it might be determined by what I find.

Stagehand,
thanks, with my settings as they currently are, we are now safely on page 2
My laptop blew up a while back and until I stop spending all my money on motorbike parts and replace the thing I am stuck using my partners overloaded and about-to-blow-up-as-well old laptop. It struggles sometimes.

Having weight to the rear of the axle makes wheelies easier

I found out today that my main frame is snapped where the sub-frame attaches to the shock mount. The back of the shock mount came off letting my subframe hang back. I have a brace on my box racks that runs down to the passenger peg n the right but the bolt rattled loose while bashing it through the woods. All that weight tugging down on that top mount caused it to snap. I replaced the bolt on my rack an it's holding it up on it's own but I'd take it as a cautionary tale. You NEED added bracing on the sub-frame. Also, use nylox nuts everywhere! That's a lot of weight bashing down...especially if you've recently discovered the joy of jumping

If you're smart you'll make the boxes quick-release and ditch 'em when you hit the trails. If you're dumb you'll make the boxes quick-release and not ditch 'em when you hit the trails. Guess which category I fall in

Well if its not one thing its another,

oh we must see video of this <-- jumping is how you break frames, but oh yeah!