Wrench therapy project bike - 96 r850r

I am the proud most recent owner of an r850r. It doesn’t run, it has been sitting in the elements for some years (most recent inspection 2014) I just started the tear down and have started a list of items to replace. 49k miles, with stamps in the service booklet from Colorado and Virginia - it was well taken care of for the first half of it’s life, at least.

I’m posting to get some experienced input on what I should be replacing while I have it torn apart. The wear items, spark plugs, fuel filter, air filter, battery, brake pads, oil-transmission-brake fluids I already have ordered. I was able to replace the fluid in the final drive and it looked good. The transmission drain bolt is rounded off, so that might prove interesting. All the plugs appear to be over-torqued. :|

The gas tank is rusted completely through in spots, and there is substantial corrosion around the fuel filler area. Rust isn’t really too bad anywhere else, strangely. I’m guessing a tank bag was left on in the elements. I’ve ordered a used tank off eBay.

Is the Poly-V belt an issue? The cam tensioner? I read in the previous thread about brake lines - that sounds wise. As much as I like to go, I might like stopping just a little bit more.

Thank you ahead of time.

When I acquired my '97 R1100R with 32K miles I disassembled the bike intending to check/lube splined shaft. With the transmission and final drive removed I inspected the clutch friction disc and found that it was marginally within specs. I made an appointment with the BMW dealership and took both the trans. and FD to the shop to have all the seals replaced. The shop did the whole job in an hour.
I bought a new clutch disc, throw-out bearing, alternator drive belt, and rear main engine seal (installed by myself). Also, I replaced the plastic fuel quick-disconnects with metal ones. It's also a good idea to replace wheel valve stems with metal ones.
Anyway, the bike has 85K miles to this date.

Metal stems

Very nice. That’s what I’m hoping for - a little TLC and some new parts and many years of service. (In addition to zen time in the garage.) My closest bmw bike shop I believe is a couple of hours away. There isn’t a motorcycle dealer with a shop of any make in my town, though I know at least one place that will work on them.

Take your time. If you need to ride now, get another bike. If you want to learn and build something of your own, take your time and enjoy the learning curve.

An alternate number for the alternator belt is a Dayco 5040240, I found some on ebay, bought 2 for half the price from dealer. for 1. I believe it is used on a Hyundai. Units I bought were made in Canada.

Thank you.

While waiting for various parts to arrive, I removed the fuel tank, which has a gallon or two of fuel the color of enchilada sauce. Fuel isn't pouring easily out of the hoses, so I'm rotating the tank around and the fuel is pouring out of random holes, along with bits of rust. I don't see a fuel filter or cutoff, so that isn't promising for the state of the carbs.

I presumed that you removed the side plate to inspect the fuel pump and fuel quantity sending unit. If the screen sock is still attached to the pump then that should have prevented most of the crud from contaminating the fuel system. Anyway, for peace of mind, I'd replace the fuel pump, U-tube connector, access cover O-ring, and vent/overflow lines. You may consider having your fuel injector nozzles serviced...project's starting to become expensive.

“...project becoming expensive...” My wife believes BMW is a acronym for “Big Money Wasted”.

A lot of the times these "builder bikes" are cheap to buy, expensive to rebuild and a ball to drive after you have paid your tuition to the "BMW University of Self Teaching".
Luckily enough, there are professors on this site that will guide you along the way.
If I my be so bold as to suggest, throw that tank and everything in it away. Get your replacement tank, make sure it is sanitary clean and replace the fuel pump and everything else inside with new components. It will be a little expensive, but in the long run you will be glad you did.
Clean the throttle bodies, replace the fuel lines.
Once you have taken care of the fuel system. See if it will fire and run. If it does, hooorayyy!!
Next turn your attention to the electrical system. If the bike is running it should not be much of a problem, Take a close look at the Halls Sensor, replace it or rewire it.

I bought an 1100R about a year ago and it's been a great riding bike, good on you for saving one from a premature grave. I just finished building mine into a pseudo-scrambler so I have some miscellaneous take off items in good shape that I was going to re-home including a front spoke wheel, forks, fork bridge and triple tree, stock shocks, rear torsion bar, gauge bezel, oil coolers, brackets and fairings, rear seat and rear side fairings (black with white pinstriping).

Someone already mentioned the hall effect sensor and I was fortunately given the same advice recently, I say fortunately because when I looked at it, the wiring was completely shot and it was only a matter of time before it left me by the side of the road. There's a member here, GSAddict, who rebuilds these to better than new, so if you need it message him and he will hook you up.

I'm trying to think of anything else I ran into when I was doing mine. I bought the cam tensioner kit but I'm pretty sure mine has already been done - i still need to pull it apart and check it but I may be selling that also. I also got a Galfer stainless braided brake line kit - there are one or two other good brands that are mentioned on this forum if you look.

Other than that, best of luck and enjoy!

derrickstone said:

View attachment 79286
While waiting for various parts to arrive, I removed the fuel tank, which has a gallon or two of fuel the color of enchilada sauce. Fuel isn't pouring easily out of the hoses, so I'm rotating the tank around and the fuel is pouring out of random holes, along with bits of rust. I don't see a fuel filter or cutoff, so that isn't promising for the state of the carbs.

Click to expand...

Yikes! That looks like the one I just replace in my old Astro van. 25 year old fuel is really nasty. Fuel tanks for these bikes seem high priced, to me. I have a 97 850r that had 25,000 miles on it. It had been serviced, so I just replaced the tires and have been riding it. Now has 36,000 ish miles. Little things are starting to need attention, but nothing horrible. I replaced the oil sight glass ( broke the first one had to order another ) It will need brake lines at some point ( could replace them now, but am unemployed Covid ) Fork seal starting to weep. I've replaced both shocks for Wilburs ( couldn't pass up a deal ) Probably needs the splines checked, but I don't have the facilities do do that at this time. I'll figure it out. So far, I really like this bike. I'm happy with it as it sits and it's been very affordable to own.

jagarra said:

An alternate number for the alternator belt is a Dayco 5040240, I found some on ebay, bought 2 for half the price from dealer. for 1. I believe it is used on a Hyundai. Units I bought were made in Canada.

Click to expand...

That belt fit like a charm.

wildwillywah said:

I presumed that you removed the side plate to inspect the fuel pump and fuel quantity sending unit. If the screen sock is still attached to the pump then that should have prevented most of the crud from contaminating the fuel system. Anyway, for peace of mind, I'd replace the fuel pump, U-tube connector, access cover O-ring, and vent/overflow lines. You may consider having your fuel injector nozzles serviced...project's starting to become expensive.

Click to expand...

Ah, the thing was a mess. I've ordered the fuel pump and filter, but the filler plate and side plate may be too rusty to reuse. The sock _appeared_ to be intact.

roninbuffalo said:

“...project becoming expensive...” My wife believes BMW is a acronym for “Big Money Wasted”.

Click to expand...

Big Money = Truth. Jury's out on the wasted part...

CNRed said:

A lot of the times these "builder bikes" are cheap to buy, expensive to rebuild and a ball to drive after you have paid your tuition to the "BMW University of Self Teaching".
Luckily enough, there are professors on this site that will guide you along the way.
If I my be so bold as to suggest, throw that tank and everything in it away. Get your replacement tank, make sure it is sanitary clean and replace the fuel pump and everything else inside with new components. It will be a little expensive, but in the long run you will be glad you did.
Clean the throttle bodies, replace the fuel lines.
Once you have taken care of the fuel system. See if it will fire and run. If it does, hooorayyy!!
Next turn your attention to the electrical system. If the bike is running it should not be much of a problem, Take a close look at the Halls Sensor, replace it or rewire it.

Click to expand...

I was able to find the same year and color tank on ebay - which cost me more than the bike. But I won't complain. While waiting on fuel tank parts - I need to source a new plate that all the pump/filter attaches to - I started on the brakes. I removed the rear wheel and removed the plate that the rear disc attaches to.

Looking at the Clymer manual, I read that the bolts needed to be heated to 120 degrees, which I did. However, I heated them to 120F, and the book meant 120C. One bolt actually came out, the other broke off without much warning.

I'm convinced working on these bikes is some kind of wizardry. I tried my trusty Snap On broken bolt remover, which broke. These things are hard! I don't know if I'm going to have to get a whole final drive assembly at this point.

slime said:

Yikes! That looks like the one I just replace in my old Astro van. 25 year old fuel is really nasty. Fuel tanks for these bikes seem high priced, to me. I have a 97 850r that had 25,000 miles on it. It had been serviced, so I just replaced the tires and have been riding it. Now has 36,000 ish miles. Little things are starting to need attention, but nothing horrible. I replaced the oil sight glass ( broke the first one had to order another ) It will need brake lines at some point ( could replace them now, but am unemployed Covid ) Fork seal starting to weep. I've replaced both shocks for Wilburs ( couldn't pass up a deal ) Probably needs the splines checked, but I don't have the facilities do do that at this time. I'll figure it out. So far, I really like this bike. I'm happy with it as it sits and it's been very affordable to own.

Click to expand...

This one looks like it was well cared for (service records) for the first 25k. The bike now has 49k, and I think it was left in someone's yard for several years. Mudwasp nests in every nook and cranny.

Because of not having a lot of dough it will likely be some months before this one is on the road. But I honestly don't mind. I don't have a lot of places to go, and having something to wrench on for a little while every night helps me sleep.

Smooth that broken bolt flat and ignore it. Use the remaining bolt to hold the disk in place while the wheel is off. As soon as the wheel is in place and the four wheel bolts (through the disk) are torqued to spec the disk will be perfectly clamped in place by the wheel bolts. Why BMW chose high strength thread locker on those tiny bolts (capscrews) escapes me. I put them back in with anti-seize.

derrickstone said:

Big Money = Truth. Jury's out on the wasted part...

Click to expand...

My wife said it not me. The BMW is my excuse to go to the garage and spend quality time with me.