Building a bike and need pointers.

[barryg]

That is a nice R100. I'm rebuilding a '74 R90/6 and have a thread on this site, kinda. I work on the bike when I can, I'm kinda in a lull at the moment. The frame is off getting some work done. A buddy is doing his work for me at the right price, free. Been in a holding pattern for a while, Any way, do a web search- Classic Bavarian Bagger. It should come up. It will show you some of the things you run into a bike build. You learn important things like perserverance, patience, trial and error, sticktoativeism, all kind of neat stuff.

 

[godfather]

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.

Thanks! Mine was a leaking greasy neglected mess when I got her. A lot of time, patience, parts and elbow grease went into the final product.

Right now she is waiting for more preventative maintenance. I will post up when I get started.

 

[zelten]

It's been a few months, as you can see, since I last posted and I am going in a bit of a new direction. I found another R100/7 with a few extra parts and an overall more complete and nicer bike so I bought it. Now I have 2. The plan is to swap what I want from the bikes and sell the 2nd.

The "new" bike is a 77 and I think that will be the one I keep unless there is a reason I should go with the 78 over the 77. I believe the 77's engine is in better shape but other than that I don't have a solid reason why I like it more, other than a "feeling" about it.
I've already received Starburags and Moly grease and I also ordered 2 sets of rear break pads and will start tearing down and repairing both bikes soon.

I have taken the rear wheel off the 78 with plans to keep the Snowflake wheels for the 77. When I did I found it slightly difficult to get the tire past the rear forks and hub. I let some air out to help and then just rocked and pulled the tire off. Is this the correct way of doing it? Is there an easier way to get the rear tire off?

Here are a few pictures of the bikes. Anything you experts see that I need to be aware of, please let me know. I have the seats, they're just off to get to the batteries.

 

[20774]

I presume the '78 is the bike in the rear. The '77 engine should be better overall from a performance standpoint as the EPA "adjustments" began for the '78s produced starting on January 1, 1978. The flattop carbs on the '78 were somewhat problematic or touchy to work with. Better take the ones on the '77.

 

[dennisdarrow]

I have taken the rear wheel off the 78 with plans to keep the Snowflake wheels for the 77. When I did I found it slightly difficult to get the tire past the rear forks and hub. I let some air out to help and then just rocked and pulled the tire off. Is this the correct way of doing it? Is there an easier way to get the rear tire off?

[/URL]

For me, the classic black is the keeper........And I would keep the spoke tires........but each has his OWN vision of what works.........

Since the tires have gotten a bit fatter over time, kinda like us, they have become to be hard to get out of between the hub and the frame.........Yes, letting the air out is one way and it works well.............Another way is to put the center stand up on 2X4's or whatever to raise up the rear end a bit........MAKE SURE WHEN DOING THIS THAT YOU SOMEWAY TIE THE FRONT TIRE/RIM TO THE FRAME or something substantial......I use the centerstand itself........AFTER I get it raised up..........The bike will want to roll forward while you are pushing and shoving on the rear tire and then guess what>>>>>>>>>>>>>Anyway, this will raise up the rear end and allow a bit more room to get a tire in and out..........

Yet again, is the method of SOFTLY, whatever that means, laying the bike over on it's side........perhaps on a cardboard box or the like......Turn off the fuel petcock first for sure..............This method allows the tire to come out from the bottom.........Really a good method with chain type bikes for sure.............God bless.....Dennis

 

[6322]

Regarding tire removal, I loosen and remove the rear axle, remove the front wheel, secure the center stand with a strap to the exhaust crossover, tip the bike from the rear forward to remove the back wheel. I usually mount the tire, seating the bead, then reduce the pressure to get it on the bike and the final check to inflate to desired pressure. Regarding differences in the two bikes, compare the rear drive ratios as they came with several. The 32/10 was always my favorite match for the '77 R100/7. Have fun with your project. Ride easy, gp

 

[zelten]

Thanks for the tips on removing the wheel. I'll try dropping straight down when I take them off again.
The 77 is the black one and the orange is the 78. Don't let the picture fool ya, that black paint job is crap. It was originally blue. Someone taped over the pin stripes, and not very well I might add, and then rattle canned the bike black. Right now I have 2 other gas tanks, so 4 altogether. But I plan to have one painted, I just haven't decided what color.

While I like the spoke wheels, they would need to be refinished and I like the snowflakes unique look.

I've read that the tachometer on the 78's were not mechanical drive. The 77 came with 2 instrument clusters, the one on it and the one now sitting on the 78. When I bought the 78 it didn't have any instruments with it. So the question is, how does the 78 connect to the tachometer?

Also, how do I check the drive ratio? The guy I bought the 77 from said something about the numbers below the speedometer but I don't know how to decipher it.

 

[20774]

The '78s used the rate of collapse of the coils to indicated RPM. There's a wire that comes off the right coil (IIRC) that runs in the harness up to the block plug at the back of speedo. It goes to a specific pin which I can't trace down right now. The '78 pinouts are slightly different than a '77.

As for rear drive ratios, look for a number stamped on the topside just aft of the connection with the driveshaft tube. That number, like 33/11, should be matched with a number on the face of the speedo, such as 1.112. Those are the combos on my '78 R100/7. Snowbum has a listing of correct numbers here:

http://bmwmotorcycletech.info/ringgears.htm