A couple Qs on my new-to-me R100RT ...

[mneblett]

I recently flew out to Colorado to look at, and ultimately purchase, a 1988 R100RT with only 14,248 miles.

I rode it back to Virginia without a hitch, and I am only just now getting the time to start going through it to address a bunch of little things. When winter sets in for real here, I'll put it on the Handy lift and strip it down to go after the more significant "stuff" (tranny neutral switch leak, pushrod tube seals, etc.).

In the meantime, a few starter Qs.

First Q: Unused bracket.

Anyone know what this bracket is for? It is bolted to the back side of the left rear frame extension, but does not terminate over anything that looks like it's missing a bolt.

My first thought is to just remove it, but I wanted to check here first to see what it is for.

Second question: Steering.

When the handlebars are turned to the left or right, after about 5-10 degrees of motion, the resistance to turning increases significantly -- just like I'm used to feeling from a BMW hydraulic steering damper. Trouble is, I don't see a damper or damper attachment point anywhere under the lower triple clamp. So did these bikes come with a damper, and if so, where is it mounted?? Or is what I'm feeling the effects of 22 year old hardened bearing grease at the steering head bearings?


Last Q (a two-parter): What is the correct routing of the speedo cable at the steering head?

In my case, the cable was zip-tied to the wiring harness and then went between the upper and lower steering trees, turning to the rear to go towards the tranny.

After cutting it free from the zip tie, the cable is routed like this (the speedo cable is the fat tube directly below the wiring harnesses):

My concern is that there seems to be an excessive amount of bending in the cable at full left steering lock:

Should the cable be routed to be coming up through the gap above the steering head reinforcement flat plate (i.e, the same hole through which the wiring harnesses are running)? In other words, what is the original OE routing for the speedo cable?

That leads to the second 1/2 of the question (and my last one, at least for a little while ): Could the routing of the speedo cable be related to continuous speedo needle bouncing at speed?

During the entire 1700 miles back from Colorado, the speedo needle bounced +/- 5-10 mph around whatever highway speed I was doing (I finally started watching the rock-solid electronic tach needle as my substitute speedo).

I'm trying to figure out whether to start with the cable as the first item to look at, or whether regardless of the cable routing, the issue is most likely with the speedo. I would not think that at 14.2k miles the speedo is worn out, but if the issue is not caused by the cable, the next thing I would suspect is insufficient speedo lubrication. Just trying to prioritize my investigation.

Thanks for your thoughts!

Mark Neblett
Fairfax, VA
A gaggle of boxers

 

[20774]

Mark -

Nice bike...I'm sure you'll enjoy that. BTW...try and reduce the resolution of your pictures next time. Your pictures are on the order of 1200 x 1000 and it would display better if they were 800 x 600. Something to think about.

As for the extra bracket, why not check with the previous owner? Then you'll know what it was used for and can decide if it needs to be removed. Doesn't look stock, though.

Check for any restrictions to the movement of the forks/bars. Somethings the wiring, cables, even the brake cables can be restricting the motion. And, yes, dried grease could be the reason. 20 years...not so old, but maybe old enough.

As for the speedo cable routing and needle bouncing...the cable could make nice smooth transitions along its route...I don't really know where it should go. Ask the PO if it's been rerouted while they owned it? Maybe the current routing came that way from the factory. But a bouncing needle could be a cable problem. If the central metal portion of the cable comes apart (it's typically a wire-wound cable), it can catch-and-release on the inside of the sheath such that the needle will respond to the stop-go nature of the spinning end of the cable. My first action would be to buy a new cable.

 

[mneblett]

Mark -

Nice bike...I'm sure you'll enjoy that. BTW...try and reduce the resolution of your pictures next time. Your pictures are on the order of 1200 x 1000 and it would display better if they were 800 x 600. Something to think about.

As for the extra bracket, why not check with the previous owner? Then you'll know what it was used for and can decide if it needs to be removed. Doesn't look stock, though.

Check for any restrictions to the movement of the forks/bars. Somethings the wiring, cables, even the brake cables can be restricting the motion. And, yes, dried grease could be the reason. 20 years...not so old, but maybe old enough.

As for the speedo cable routing and needle bouncing...the cable could make nice smooth transitions along its route...I don't really know where it should go. Ask the PO if it's been rerouted while they owned it? Maybe the current routing came that way from the factory. But a bouncing needle could be a cable problem. If the central metal portion of the cable comes apart (it's typically a wire-wound cable), it can catch-and-release on the inside of the sheath such that the needle will respond to the stop-go nature of the spinning end of the cable. My first action would be to buy a new cable.

Thanks for the comments, Kurt.

I will reset my photobucket presets -- I thought the import default was set at 640.

Thanks for the suggestion re: ask the PO. However, while the PO was a nice guy/great to deal with (even offered me a room overnight and picked me up at the Denver airport) and I'm quite sure he would not mind the Qs, I don't want to bother him with little stuff -- with all the Qs I could come up with, it would be like he'd never been able to divorce himself from the bike!

I have verified that the wiring harnesses, cables and brake hose are all clear/not inhibiting motion. I just went out and did one more check -- I noted that the resistance is not angular velocity-dependent, i.e., rather that getting stiffer with faster turning, it remains constant, or even eases a bit. That sez old bearing grease to me. From what I know about the bike (including paperwork all the way back to the original purchase in N.H.!), I'm pretty certain the steering head bearings have never been serviced, so that will be one more thing on my list.

On the speedo cable, it is new (the PO gave me the removed, and still in apparently good condition, speedo and clutch cables for emergency spares). For all I know it is correctly routed; just seemed like too much bending at left lock. Mostly, I wanted to see if there was some way I could rule out the speedo cable as the source of the bouncing needle before I turn to the speedo itself. I still need to pull the tank at some point to verify there are no kninks anywhere along its length, but I have no reason at this point to think the cable is damaged.

Thanks again, and keep the comments coming, folks!

 

[88bmwjeff]

That extra bracket is for the overflow tube for the battery. Chances are the battery was replaced with a sealed unit, which does not have an overflow tube.

 

[Yarddog]

That bracket almost looks like it bolts to the exhaust clamp that's right under it... I wonder if you took that clamp off and changed it's orientation if the end of that bracket wouldn't line up with the clamp bolt...

With regard to the speedo jumping, mine does the same, and I believe it's because it needs lube inside...with all of my other stuff, you simply remove the cable from the housing and use white grease to lube it as ya stuff it back in...in looking at other posts on this forum, it seems like the cables from your vintage scooter are plastic lined, and are not lubable, so I'm thinkin' that if you have a sharp kink in the cable as you have described, that's yer problemo...

 

[habdala]

Sccot

Nice bike!

 

[mneblett]

That extra bracket is for the overflow tube for the battery. Chances are the battery was replaced with a sealed unit, which does not have an overflow tube.

Bingo! I believe you are spot-on, Jeff -- the bracket is perfectly positioned for that purpose, and the relatively new battery in the tray is a sealed unit. I learn something new every day

Thanks!

p.s. -- and I like your taste in BMWs

 

[mneblett]

That bracket almost looks like it bolts to the exhaust clamp that's right under it... I wonder if you took that clamp off and changed it's orientation if the end of that bracket wouldn't line up with the clamp bolt...

Good thought, but no go for location/orientation/hole size. I believe that 88bmwJeff has nailed it.

With regard to the speedo jumping, mine does the same, and I believe it's because it needs lube inside...with all of my other stuff, you simply remove the cable from the housing and use white grease to lube it as ya stuff it back in...in looking at other posts on this forum, it seems like the cables from your vintage scooter are plastic lined, and are not lubable, so I'm thinkin' that if you have a sharp kink in the cable as you have described, that's yer problemo...

From what I've read, I believe I will need to get some lube up into the speedo head itself. The cable does not appear to be kinked anywhere in view. The part of the cable I can't see should be a relatively straight shot back to the tranny. At this point, unless just shooting some HKS grease (sprays as a light oil, dries as a grease) up into the cable drive will do the trick, I'll probably hold off doing anything until I take the bike apart and have the instrument cluster on the bench.

 

[mneblett]

Nice bike!

Thanks -- I feel pretty lucky to have found a 22 yo RT with only 14k on it *and* in overall good condition (i.e., not 14K from having sat unused somewhere for the last 15-20 years).

 

[Yarddog]

I've had the speedo head apart a few times and I wouldn't put anything like grease in there...a light teflon lube at most, and the guys who've done the odo work in there have actually recommended silicone lube...I myself am REAL leery about anything involving silicone on a motorcycle, car, truck, whathaveyou because of the effect it has on future paint jobs...but there ya go...

 

[kstoo]

My old '88 had the wildest speedo needle ever, I never did figure out what caused that.
I think that you guys are right about steering bearing grease. If this is a 21 year old bike with only 14k on it I bet it has never had the steering bearings serviced.

 

[mneblett]

I've had the speedo head apart a few times and I wouldn't put anything like grease in there...a light teflon lube at most, and the guys who've done the odo work in there have actually recommended silicone lube...I myself am REAL leery about anything involving silicone on a motorcycle, car, truck, whathaveyou because of the effect it has on future paint jobs...but there ya go...

Thanks -- that probably saved me another "well, dang it!" moment.

 

[evergreen]

Hi Mark:

I think the drag you are feeling is coming from the rubber fork gaitors. They are pretty stiff. When I serviced the front end and forks two years ago, the gaitors were loose and basically fell down around the fork tubes whenever the handlebars were turned. I think you will find if you remove the gaitors, the steering turns freely.

When the cable was replaced, I took care to route it the same way as the old one. I suspect that the one you have as a spare is the original. I replaced it because the needle bounced but little change was noted.

I did not replace the steering head grease, and am certain it is the original stuff in there.

Have fun with the bike!

Greg

 

[20774]

I think the drag you are feeling is coming from the rubber fork gaitors.

At first, I thought the same thing. I checked the initial post and didn't see any gaitors on the bike...assuming that picture was of the bike in question.

 

[mneblett]

Hi Mark:

I think the drag you are feeling is coming from the rubber fork gaitors. They are pretty stiff. When I serviced the front end and forks two years ago, the gaitors were loose and basically fell down around the fork tubes whenever the handlebars were turned. I think you will find if you remove the gaitors, the steering turns freely.

When the cable was replaced, I took care to route it the same way as the old one. I suspect that the one you have as a spare is the original. I replaced it because the needle bounced but little change was noted.

I did not replace the steering head grease, and am certain it is the original stuff in there.

Have fun with the bike!

Greg

Greg -- thanks! I didn't want to bother you, but your input is greatly appreciated

I'll take a look at the gaiters again, but the marked change in resistance occurs before the gaiters begin to stretch much.

As to the cable, somehow I expected that you put the cable back just as it was With your comment, I now know to pursue the speedo head next.

Thanks!

 

[shire2000]

I have had a few speedo's that have waved all over the place. When I bought my current R100RT the speedo would wave from about 10MPH to 80MPH whenever I was doing anything over 20MPH, I think. So first thing I did was check the cable, disconnected it at both ends and turned it and found notchiness. So replaced the cable, and then speedo only waver about 10-15MPH either side of what I was actually doing. So pulled the speedo out of the casing, used a light air to blow out any dirt and dust, then lubed everything with a very light silicone based lube, just enough to make certain it was lubed, but not so much that it dripped or puddled. Put it all together and now the speedo is rock solid, runs smoothly from 0 all the way to pinning it.

Yes, it is the 85MPH speedo, so once I crank it past 85, I am unable to answer the question the officer asks "Do you know how fast you were going?" I can always say "Speedo indicated 85MPH, Sir."

 

[mneblett]

At first, I thought the same thing. I checked the initial post and didn't see any gaitors on the bike...assuming that picture was of the bike in question.

These aren't the typical fork leg gaitors, but the oblong rubber seals that seal the holes where the fork legs pass through the fairing -- completely hidden in that pic.

 

[squiffynimrod]

Fork gaitors

My vote is for those as well. Mine were loose on the 100, if I dropped them down the steering went lock to lock without much resistance. Putting them in to place increased the resistance to the point that I looked again and checked if anything was wrong. I go with them in place, and have some reduced low speed maneuverablity.

Steve

 

[20774]

These aren't the typical fork leg gaitors, but the oblong rubber seals that seal the holes where the fork legs pass through the fairing -- completely hidden in that pic.

Thanks...I've never spent any time looking down from the perch of an RT to remember that!

Not really gaitors then, maybe more of an apron or "diaper" or actually I think they used to have something called a "dryper". Check out this page under accessories for the Luftmeister fairing:

http://www.omnilex.com/public/bmw78/bsa2.jpg

I have one of those; it's kind of x-shaped and is supposed to fit between the forks and ride up inside the well created by the inside of the fairing. When I would use it, the edges would fold up and kind of defeat the purpose. I tried some coat hangers in a criss-cross fashion to maintain the flat shape but later just abandoned it all together. Now I just don't ride in the rain!

 

[88bmwjeff]

At first, I thought the same thing. I checked the initial post and didn't see any gaitors on the bike...assuming that picture was of the bike in question.

Well, they're not gaitors perse, but there are boots, as BMW calls them, located at the bottom of the fairing, and do provide more resistance the more the handle bars are moved.