spacewrench Posted June 18, 2019 Share Posted June 18, 2019 I know there are several different options for moving R1100S bars around (I have the Suburban Machinery bar-riser kit). But I could use a lot more up & back, and rather than dropping $200 for more exquisitely-machined adapters that don't quite go far enough, I figured I'd look into alternate approaches. So: Does anybody know if the top triple from other bikes of the era (e.g. R1100R, RS, RT) would have the same fork and upper steering pin spacing? You can get triples for $20 or so on eBay, and I figure I can get the fork holes bored out as necessary, and then just use stock R/RS/RT taller bars (also pretty available, pretty cheap). Link to comment
Lowndes Posted June 22, 2019 Share Posted June 22, 2019 Hey, Spacewrench, Do you already have the bars clamped to the tubes above the TC?? Link to comment
spacewrench Posted June 23, 2019 Author Share Posted June 23, 2019 (edited) Yes, that's the mod that the Suburban Machinery does. You slide the fork tubes up ~3cm and move the clipons to the top side of the triple. I've been looking at similar-year R1100R, RT, RTP and GS front ends on eBay. A Rockster (1150) front end would allow me to switch to superbike bars, with almost complete freedom to choose rise & pullback. RT front end has the bolt-on bars, but lots of rise & back. If the fork tubes are the same diameter and lateral spacing, I could keep the R1100S lowers and just replace the TC and tubes (the non-S tubes appear to have different tube/TC interaction, so it looks like it'd be easier to replace the TC if I have the corresponding tubes) Edited June 23, 2019 by spacewrench Link to comment
Lowndes Posted June 23, 2019 Share Posted June 23, 2019 I have a set of RapidDog bar backs somewhere. Want to try those?? http://rapiddog.net/ Link to comment
wbw6cos Posted June 23, 2019 Share Posted June 23, 2019 Hi Lowndes, are you an S-aholic too? Link to comment
spacewrench Posted June 23, 2019 Author Share Posted June 23, 2019 36 minutes ago, Lowndes said: I have a set of RapidDog bar backs somewhere. Want to try those?? If I can send 'em back to you if they don't work, that'd be great, thanks! They look terrific, but too spendy to have them wind up in my "spare parts" bin. That's why I was looking into the "REALLY move the bars a long ways" options...I figure if I was able to go too far up & back, I'd have a useful reference point, rather than a series of "well, this is better than before, but I bet another couple inches would be mo' bettah." Are you anywhere near Portland OR? Link to comment
Lowndes Posted June 24, 2019 Share Posted June 24, 2019 On 6/23/2019 at 5:35 PM, wbw6cos said: Hi Lowndes, are you an S-aholic too? Well, I was. The S was my first bike since maybe '78. My brother drives it now. It sure does handle well!! I did every bolt-on mod I could find, AFXied, SJ air filter and BP Induct, GS 12 injectors, Wilbers, even put a new clutch in it with the extended splines. I have a set of Rocket Sprockets somewhere, never put them on. It came with the Corbin smuggler seat. LOVED that bike. Then I saw a few old K bikes, flying bricks, at a rally and started looking around. Bought this K1200RS from a Russian guy in SC. It has almost twice the HP. I rode the S last fall just for ole times sake and it felt like riding a bicycle after the K, short, skinny, and light. 1 Link to comment
spacewrench Posted June 29, 2019 Author Share Posted June 29, 2019 Well, I got an 1150R triple clamp & fork tubes, so I guess I'll find out whether it fits! The fork spacing looks the same, but the distance from the fork-to-fork line to the steering pin might be a little smaller, which would reduce the head angle, I think. I guess that makes the steering slower. It also looks like the location of the necessary degrees of freedom for the telelever front end will move from the ball joint in the steering pin (R1100S) to the tops of the fork tubes (in the R1150R setup). Can anybody with more mechanical intuition than me, guess whether this has a chance of working? Link to comment
Lowndes Posted July 2, 2019 Share Posted July 2, 2019 Are the tops of the down tubes the same on both?? From your pics on 7-23 they look very similar. And, are the threads for the "steering pin" the same?? One sure way to find out if it will work!! Well, that and ask Dirtrider. Link to comment
spacewrench Posted July 2, 2019 Author Share Posted July 2, 2019 The R1100S tubes are clamped into the upper triple (same as standard fork tubes). The R1100R tubes have a bolt sticking out of the top, which goes into a rubber-mounted thing (3) in the upper triple, allowing the fork tube to wiggle around like a joystick in a gimbal. Conversely, the R1100S steering pin is a ball joint (2), whereas the R1100R steering pin (6) is a plain bolt mounted in a bearing (5) (so all it can do is turn). The threads on the R1100R pin might be the same as the R1100S ball joint, but I think the length is different. I'll have to either adapt the R1100S ball joint to the R1100R bearing cavity, or make a spacer to extend the R1100R pin (I think the spacer will be easier to machine). The thing I don't understand about R1100x steering is, the upper and lower triples are not connected by a steering stem, the way they would be on a normal bike. So when you turn the bars, you're twisting the upper triple, but the lower triple just gets dragged along by the fork tubes. I know the fork tubes and sliders are pretty sturdy, but it seems like there's still some room for "wind up" in the steering, where you turn the bars, which torques the fork tubes around each other a little bit, and finally that twist drags the front wheel around to where you're pointing it. I'm not a good enough rider to detect it, but I wonder if "twisty, flexible, slow-responding steering" is a complaint of people who ride these bikes hard. R1100 Front End.pdf Link to comment
Lowndes Posted July 2, 2019 Share Posted July 2, 2019 The front end of my S is box stock as far as I know except for Wilburs front and rear and Michlin PR4's. I'm not an expert or "racer" but I did ride that bike HARD at times all over the mountains on GA, SC, NC and TN. I can tell you that it handles WAAAAAAY better than I can drive it. A simple proof of that is that I frequently ride with only one hand on the bars and it handles NOTICEABLY better that way (the less input from me the better - kinda like being married). I have never noticed ANY looseness or twisty, flexible, or slow responding AT ALL. Quite the contrary. Just hold the front wheel firmly between your knees and try twisting the bars. I have read, in this forum I think, of riders having a badly worn ball joint between the lower TC and telelever. You might check yours for play/wear while you're there. Also check the steering damper. If you still have the OEM Showa shocks and more than 30-40K miles, its time for new units front and rear. Call Ted Porter at The Beemer Shop and talk to him about what he recommends and uses on his S. He can explain the front end geometry, too. https://www.beemershop.com/ I still can't understand why the front doesn't dive with braking like regular fork tubes. It's easy to see with an Earls but not a telelever. Link to comment
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now