BMW R80

[davidcumbria]

Wanted to try something different to restore after the 550k1 so have got a slightly unloved but running 1986 R80,  not the faired touring rt  one just the naked lighter bike. My daily rider is 1999 1100 GS and I’ve owned several 1200 GS so I could see the lighter lower R80 as a bike I could enjoy long term. The 800 has a reputation as the smoothest airhead and it does have that feel.  Restoration will be next winter but my initial research makes me think self restoration of the gearbox is probably out due to special tools, intricate shimming and a press needed which is slightly disappointing and makes me reflect wistfully on the ease of doing the 550. Anyone here with any experience or thought on a BMW airhead ?

[Bryanj]

Only ever had to do clutch and pushrod seals so cant really help there as they were always reliable

[K2-K6]

No experience on that bike from me either.

Does the gearbox have any problems now  ?

If not, then an oil change to look a what's in there (presuming it's seperate lubrication? ) and check through for specular particle etc would be worthwhile prior to the general restore.  Could be fine without strip and attention, with dedicated gearboxes unlikely to be compromised if lubrication has been OK through life.

If it's EP oil spec in there, my "favourite" oil is Motul EP 75w80 if that's in compatible range from specification.

[Johnwebley]

I have a thought, the joints and the  splines on the shaft drive,

I know a friend that had a K brick had issues

Sent from my SM-A546E using Tapatalk

[Bryanj]

The early K's had some problems but they were inline 3 or 4 cylinder bikes, i was taught by a good bm mechanic how to stop tappet rattle and will pass that on if you wish

[Laverda Dave]

Matt Hull the editor of Classic Bike Guide has spent the last year or two restoring a RS100. Every month there's an update and a how to type feature. He got it back on the road but after a few hundred miles he had the death knock and has had to strip it down again. Problem turned out to be a failed main/big end bearing, something he didn't attend to in the first rebuild as he was told these never give problems!
He's made some home made tools along the way such as puller's etc.
I know it's not the R80 but probably transferable information between the two. Well worth a read & subscription 👍.

[DomP]

There's something about those engines I love,  they look so neat, who'd have guessed they were German.

[Orcade-Ian]

Hi Dave,
I've had an R65 many years ago and an R100 RT Classic more recently. Engines are virtually bomb-proof - if servicing has not been skimped.  Depending on the year, gearboxes can be troublesome. Not sure of change points but early bikes had a circlip holding a bearing in place.  BM accountants decided it wasn't necessary as the bearing couldn't come off the shaft!  True, BUT it could move and cause bearing failure.  Saved them a few pence on each bike. Many replaced under warranty, so the circlip was refitted and the groove re-introduced.  My 95 R100 had the groove - a friends 88 R80 didn't.  I made a rig for the lathe to re-machine the groove in the hardened shaft with a thin grinding disc in the dremel.  All gearboxes can suffer from gearchange spring failure which leaves you in whichever gear you were in when it failed.  A few special tools needed to strip the box and the casing has to be heated to get everything out.  I made the tools and gave them to the mate with the R80 but could beg them back if you needed them.

http://www.stallard-engineering.co.uk/stories/Bikes/European/BMW%20Gearbox%20Tool.htm


Ian

[Orcade-Ian]

Another page on the site that I'd forgotten I had posted - am I getting old?

http://www.stallard-engineering.co.uk/stories/Bikes/European/BMW%20R100RT%20Part%202.htm

Ian

[davidcumbria]

Thanks Fellahs those are very interesting and helpful replies. I will start reading up on classic bike etc and could be interested in those tools Ian. Impressive that you have the skills and kit to make them. Nothing happening very soon on this but great to know you guys have got my back 👍

[flatfour]

I've owned BMW airheads on and off since the 1970's when I had one of the last R90S's into the UK.

I think that Matt Hull (Classic Bike Guide) did say that the bottom - end problems on his bike came through low oil level. Most of the older boxer engines had a real thirst for oil and on touring trips with other owners, often at the end of a long day's ride on the continent, we would buy a gallon of 20/50 and share it between three or four bikes. There was never any left in the container!

My understanding is that both the gearbox and shaft drive is difficult to self - service though there are a few well - known businesses that offer overhaul if needed.

Perhaps it might be worth joining the BMW Club, which has lots of information available, as well as a tool hire service for DIY work that includes nearly all of the special tools ever offered by BMW?