Building a bike and need pointers.

[zelten]

Hello everyone. I have owned one BMW in the past, a 2004 R1100S, and I had to sell it when I just couldn't justify it taking up much needed real estate in my very small garage when I didn't ride it during the winter. I only owned it 2 years but I put close to 20,000 miles on it in that amount of time. I've moved and now have a bigger garage and want to build a cafe racer using R100 parts.
As of now I have the frame to a 1992 R100R. That's it. Just a frame. I plan to source all the parts I need to build my dream bike. I'm doing it this way for a few reasons.
1) Hopefully it will be cheaper than buying a bike and then removing parts and altering it to what I want.
2) I don't want to ruin a bike that has a chance of being restored by building a cafe out of it
3) I may be crazy but I want to see if I can do it
4) I can say I built the bike myself

I have a Clymer manual now to help me when I start to put things together but my main problem and what I hope forum members here can help me with, is, knowing what parts I can use with what parts and to gather opinions on what should be used.

My idea is to have a very minimalist bike. Only what is needed. Ideally it wouldn't even have electric start but I'm not sure if that's possible. I'm hoping to end with an R100 engine (I don't have a choice of year yet) with a kick start transmission. Duel front disk brakes would be great and stock exhaust would be fine. I want duel shocks on the rear with a single seat in the style of a 1953 R25. That's about the most details I can give right now.

I have been trying to research what I can use and which year parts to stay away from but I thought it would be easier and more helpful if I had an ongoing dialog with more knowledgeable people. That has served me well with other projects I have tackled in the past.

So I would like to thank everyone in advance and ask for forgiveness for any questions that I may ask that have been beaten to death in the past and dive right in.

Where can I find the answer to or what is the answer to the question, what year R100 engines will fit on a 1992 Frame?

That should be enough for my first post.

Thanks again and I look forward to learning!

Mitch

 

[typ181r90]

Mitch, welcome to the forum. Here's my 2 cents.

If you're set on a kickstarter you're going to have to go with a /5 4-speed trans as the kickstarter on early 5-speed transmissions was prone to breaking. I don't think you're going to like the 4-speed combined with an R100 engine. Also, the 92 R100R was a monoshock bike, you'll have to modify the subframe and use an earlier swingarm. The single seat you're referring to will also need a frame modification, but if you can weld and design your own brackets that's not really a big deal.

FWIW, I'm doing the exact same thing you're doing with a 1957 R60 and it's proving to not be any cheaper than buying a complete bike - though in my case I'm doing it to essentially space out payments and start with new parts. However, this is with an early bike where parts are more expensive and the complete bikes (unrestored or not) are quite expensive. I honestly think you'd be better off buying a complete bike from the 70's and working from there as the airheads really aren't all that expensive to buy complete bikes, especially ones that would be ideal candidates for what you want to do. They'd already be set up for dual shocks, have the right swingarm and final drive, and may have a kickstart depending on the year - if you want dual disks on the front, it's really not a big deal to swap out fork sliders and handlebar controls.

When I cafe'd my R90/6, I didn't feel bad about it because it was so far gone from stock when I bought it, it had a /7 tank (which is the tank I was going to put on it anyway), aftermarket seat, non-stock paint, and huge fairing. It also needed some mechanical TLC right off the bat, but it ran and other than a final drive rebuild, it was stuff I could do while riding. In other words it was a runner that probably wasn't worth restoring and an excellent candidate for modification - that cost me 3K. Take a look at bikes for sale around you, then take a look on ebay or forums for parts a do a quick budget, I think you'll be amazed at how fast things add up. It's much easier to subtract and modify than it is to start with nothing.

EDIT: Something else to consider, with the price of parts relatively high, if you bought a whole bike you could sell off what you don't need to finance what you want - like that single seat. Here you can see a before and after (note, the original was actually not nearly as nice as the pictures indicate). That big obnoxious fairing, sold that to finance parts for my R60, but for what I sold it for you could buy a nice seat and a SJ Triple Clamp like I have. Or the clip-ons, and so on and so on. Again, I like your idea, and I'm doing the same thing (at a snail's pace), but you're going to way overpay if you want to build an airhead cafe if you're just building it up with parts. See the blog in my signature for the progress on my R60 (to see how slow going it is), or even to see how I built my Aermacchi special - which did require frame mods and welding new ears on a non-stock tank to make it compatible.

 

[godfather]

Mitch, welcome to the forum.

..........I honestly think you'd be better off buying a complete bike from the 70's and working from there as the airheads really aren't all that expensive to buy complete bikes, especially ones that would be ideal candidates for what you want to do. They'd already be set up for dual shocks, have the right swingarm and final drive, and may have a kickstart depending on the year - if you want dual disks on the front, it's really not a big deal to swap out fork sliders and handlebar controls. ........

+1....you will be $,$$$ ahead and still have what you want.

 

[pranda]

Minimalist bike

A guy who rides 20,000 miles in two years needs just about everything that comes stock on an Airhead . Most add stuff .
I ride a '87 R80 with an S fairing , and about the only thing I don't use regularly are the turn signals ; leave the bags at home if not needed .
My home is about 50 miles from a large city , many beautiful mountain roads around , and I see many bikes come through ; mostly touring bikes , some rocket bikes , vintage etc. , the highly customized bikes stay right in town . Can't imagine doing 10,000 miles a year right in town .
Why not get a complete Airhead that is closest to your liking and ride and maintain it for a while , get to know it , make it your own . That will give you time to study the different models , and what works , and what doesn't . Then decide what to take off .
I chuckle to myself when I see a picture of a bike with no fenders and a tractor seat ; where does the water go ?
People are constantly parting out bikes because the parts are worth more than the whole .

 

[lmo1131]

There's a few pointers in this old thread, all 77 pages of it >>> http://forums.bmwmoa.org/showthread.php?51716-Complete-Restoration-of-BMW-R75-5-into-Cafe-Racer

And just so ya don't have to read all the way through it to see how it turned out...

And +++++++ 100 on starting with a running machine. They way you're headed sounds like a set up for it end up stashed in a corner of your bigger garage. Not sayin', just sayin... .. .

 

[zelten]

I took everyone's advice and decided to buy a 1978 R100/7. It's in running condition and over all a solid bike. It's already been molested enough that I don't feel bad about customizing it but I won't be going as drastic as I first planed. I'm going to keep it simple to where it can be brought back to stock configuration if desired later. I'll post pictures later if any one is interested.

Thanks For the advice

 

[franko]

Oh Yes I would like to see it. Before, during and after. Frank coleman

 

[zelten]

I'll try to put some pictures up tomorrow.

 

[wyman.winn]

There's a few pointers in this old thread, all 77 pages of it >>> http://forums.bmwmoa.org/showthread.php?51716-Complete-Restoration-of-BMW-R75-5-into-Cafe-Racer

And just so ya don't have to read all the way through it to see how it turned out...

And +++++++ 100 on starting with a running machine. They way you're headed sounds like a set up for it end up stashed in a corner of your bigger garage. Not sayin', just sayin... .. .

DAMN!!! that sure is purdy....

 

[ratze]

Personally i wont ride a bike that i have not massaged every nut and bolt on it, for me that is 75% of the ride. an heck yea she shur is purdy, an WOW what a project.

 

[zelten]

So this is my bike. One 1978 R100/7. I really have no history on her and as you can see she has been modified slightly already. I won't have time to really touch her until after the holidays, but this is it. I've only put about 4 miles on her. I doubt I'll ride again until I'm finished. I plan to take her to the frame and build back up from there.

 

[lmo1131]

I doubt I'll ride again until I'm finished.

That is probably a very good plan of attack. If you were to start riding it frequently, more than likely you wouldn't want to stop.

 

[zelten]

That is probably a very good plan of attack. If you were to start riding it frequently, more than likely you wouldn't want to stop.

I'm tempted to get out and riride every sun break!

 

[jstrube]

TYP181R90, what seat did you use? I have that exact seat & do not know where it came from.

 

[typ181r90]

TYP181R90, what seat did you use? I have that exact seat & do not know where it came from.

I bought it from BMW Bayer in Germany, though I think a few vendors sell it. It's a 1.5 seat Giuliari replica, only ones I've seen available have been made in Germany.

 

[typ181r90]

I took everyone's advice and decided to buy a 1978 R100/7. It's in running condition and over all a solid bike. It's already been molested enough that I don't feel bad about customizing it but I won't be going as drastic as I first planed. I'm going to keep it simple to where it can be brought back to stock configuration if desired later. I'll post pictures later if any one is interested.

Thanks For the advice

You made the right call, looks like a great candidate for a build.

 

[nickrides]

Hey Zelten
Don't forget to turn those gas petcocks off when you leave your airhead in a garage or any other place a gas spill could cause a fire.
If those carbies decide to spring a leak [ been there ] ........
don't want to blowup that sweet VW van!
Have fun
I've got a nice 1978 R80/7 FWIW

 

[godfather]

Good call zelten. You have a great base there to customize....
HAVE FUN! Keep us posted as what you're doing with lots od photos.

I had original plans to do something cool to my 78' R100/7 but ended up keeping her all original.

 

[zelten]

Hey Zelten
Don't forget to turn those gas petcocks off when you leave your airhead in a garage or any other place a gas spill could cause a fire.
If those carbies decide to spring a leak [ been there ] ........
don't want to blowup that sweet VW van!
Have fun
I've got a nice 1978 R80/7 FWIW

Yes I need to turn those off. I totally forgot that. Thanks. No I don't want my Bus to blow up, that's my baby there.

 

[zelten]

Godfather, your bike is beautiful. I don't think I could have touched it either. I plan to tear mine down to the frame and go over everything. Because I know nothing about it's history, I don't trust it enough to get out on the road yet, besides, Seattle winters...and spring...and early summer can be wet, so I have time to rebuild her. I'll keep ya'll updated with my progress.