Dump the Damper

[Paul De]

If your bike does not any suffer ill effects of not having a damper, then maybe you can forget about replacing it.   The most likely scenario of instability would be when decelerating you might note some tendency for the handle bars to self oscillate.  However, I suspect it might not be a problem as the Telelever rake and trail numbers don't decrease significantly like they would with a standard front fork under strong deceleration.

[dirtrider]

6 hours ago, Blue7 said:

From North Italy through Les Orres mountains into France, a long day yesterday with no damper. All better than with my gummy damper included. Again I will look into a replacement damper later but the sheer panic I sometimes read about not having a damper misses some practical concerns. I realize also I probably, because of preference, will need risers and hopefully wider bars to get to where I'm comfortable. All that for another thread of course but any insight welcome for those things. Regardless, you fine gentleman have been very helpful with insights as I learn more about my R850R purchase.

Afternoon   Blue7

 

Pretty country, it's been a while since I have traveled in northern Italy. (I kind of miss my trips to that area)

 

You probably won't know that you need a steering damper until you DO. I have owned a couple of Boxer R bikes in my life, an 1100R & an 1150R. For the most part they were pretty stable at lower speeds with a light motorcycle loading. 

 

My R bikes seemed to show the worst head-shake tendencies at higher speeds when catching or crossing air currents behind large tractor trailers. Not too bad with a naked R but with a  fork mounted windshield & large handguards it could just pop up unexpected (especially with rear panniers & a top case).  Those air vortices off the rear of those large trailers could catch the windshield just right then it would shake it's head, if I stayed on the throttle it would usually calm down on it's own  but if let off on the throttle it could get pretty violent. Didn't happen a lot but I always knew that it could. This was with the factory steering damper but those didn't do much after they became worn.  

 

BMW wouldn't have put that steering damper on those R bikes if they didn't think it was needed!  

 

  

[Blue7]

OK. I am safe and sound in Barcelona from Silesia, Poland where i purchased the bike. Half the ride from southern Swiss Alps through Italy and France to Spain and no issues with not having damper. I will continue to consider a replacement damper, but I was happier without my grabby gummy damper for the rest of the ride, but just as a report, without any seriously weird stuff happening to me on the road, like being hit from behind or the side by hydroplaning autos, all was fine. Thank you all for your inputs and I will continue to ruminate on all of them as I go along. One final question: What is the going thoughts on WHAT CAUSES tank slappers? What are the common reasons everyone agrees on? Someone here mentioned quick deceleration? Another person mentioned drafts behind large trucks?, but what are the agreed upon reason why they happen? [[AS a side note but to answer some of my own question: I test rode an early 80s R100RS once. When i got up to about 45 kph the front end went wild with insane back and forth shaking. I tested it for 45 minutes in many situations and it was an insanely crazy shake at that same speed. When I took it back to the seller and told him about my experience, he shook his head and said it never happened to him. I saw him ride off with the moto an there was truly nothing happening to him. The only difference was I was a tallish slim guy and he was a tallish fat guy. I presumed there was just something about the weight distribution.]] You are all fine gentleman for taking the time. Attachment is the bike praying for no tank slappers in the Italian influenced Switzerland.

[dirtrider]

1 hour ago, Blue7 said:

 One final question: What is the going thoughts on WHAT CAUSES tank slappers? What are the common reasons everyone agrees on? Someone here mentioned quick deceleration? Another person mentioned drafts behind large trucks?, but what are the agreed upon reason why they happen? [[AS a side note but to answer some of my own question: I test rode an early 80s R100RS once. When i got up to about 45 kph the front end went wild with insane back and forth shaking. I tested it for 45 minutes in many situations and it was an insanely crazy shake at that same speed. When I took it back to the seller and told him about my experience, he shook his head and said it never happened to him. I saw him ride off with the moto an there was truly nothing happening to him. The only difference was I was a tallish slim guy and he was a tallish fat guy. I presumed there was just something about the weight distribution.]] You are all fine gentleman for taking the time. Attachment is the bike praying for no tank slappers in the Italian influenced Switzerland.

 

Morning   Blue7

 

This is a BMW motorcycle forum, you probably won't find   "common reasons everyone agrees on"    for ANYTHING.

 

There are a number of causes & effects of wobble or headshake. Some major & some minor. 

 

Some can start out as a slight front wobble or oscillation then progress into a full-on tank slapper (these are usually not too bad as they give you that early warning of something about to happen).  

 

But some can just go into a full wild tank slapper with no pre-warning (like turning on a light switch). These can be bad as with no, or not much, warning the rider isn't ready to deal with it, plus if it is violent enough, or your hands are not firmly on the grips, it can rip the bars out of your hands with the bar movement so violent that you can't regain a grip on the wildly oscillating bars.  

 

What causes (or effects) can be caused by a number of things but usually it takes a few things working together to cause a hard continuous head shake.  (all it needs is a reason & energy added)

 

Almost every motorcycle has an inherent instability or wobble point,  the desirable is to have that point in the speed/loading range that you never ride at. 

 

It takes input energy for a wobble to go into a violent head shake, this energy usually comes from the front tire but it might not be the front tire that initiates the shake. 

 

On motorcycles with fork mounted fairings or windshields some of that input energy can come from wind reaction force on the fairing or windshield, or even on handguards if the wind catches them at just the right angle then releases as they move to a different angle to the wind.   

 

Front end geometry can have an effect, both front & rear tire wear can have an effect, tire design/construction/tread pattern can figure into front end shake. Such as a tire with straight ribs (used to be a common motorcycle tire design) ridden at certain speeds on grooved pavement can cause great instability & even a significant head shake (us old timers remember that problem). 

 

Tires that have a lot of restoring force built in coupled with a front fork assembly with very little rotational damping friction can be tame as a house cat under most riding conditions but suddenly turn into a man eating tiger by hitting a little bump, or by a little tire dynamic imbalance at a certain speed,  or even a small gust of wind catching the front end just right. 

 

On the BMW 850/1100/1150 boxer bikes there is also a tracking offset as rear wheel typically does not track directly behind the  front wheel (tracking offset). The BMW specification allows a fairly generous tracking offset & still be within specs.  

 

Motorcycle wheel base  can also figure in as well as well as  rear wheel stability (instability), or even rear weighting, and/or rear wind catching things like paniers or top boxes. Anything that can initiate the front wobble condition, then the input energy into the front can keep it going or even increase the shake intensity. 

 

If the head shake trait is baked into the motorcycle design,  or baked into the suspension angles or loading then about the only band-aid  is to add some rotation friction to the front end. Too much friction & the steering gets heavy or lagging, too little & there isn't enough damping to prevent the wobble, or worse yet, prevent the wobble from adding more energy & getting worse until the point of bouncing the wildly oscillating forks off of the steering stops. 

 

 

[Blue7]

I think I understand most of what you write, Dirtrider. Thanks. So, if I want to put a new damper on, I think I want something that does absolutely nothing until extreme crazy stuff, so what would that be? Are there aftermarket dampers to recommend that don't kill my wallet? (To remind, the reason I took off my damper was because it was sticky and gummy in all situations where i had to use normal quickness to steer, like in a U-turn stopped on a road or quickly turning to adjust for holes on the side of the road or in parking lots etc., all in relatively slow situations. That gummy damper made it all more dangerous and really difficult to turn at inopportune moments.) In the end, I think i want something for extreme circumstances otherwise i want it to act like it's not there, right? Any recommends for brands that make dampers for the 1999 R850R where I can get this? Eventually, if it matters, this bike will indeed have wife on back and loaded cases everywhere.

[dirtrider]

1 hour ago, Blue7 said:

I think I understand most of what you write, Dirtrider. Thanks. So, if I want to put a new damper on, I think I want something that does absolutely nothing until extreme crazy stuff, so what would that be? Are there aftermarket dampers to recommend that don't kill my wallet? (To remind, the reason I took off my damper was because it was sticky and gummy in all situations where i had to use normal quickness to steer, like in a U-turn stopped on a road or quickly turning to adjust for holes on the side of the road or in parking lots etc., all in relatively slow situations. That gummy damper made it all more dangerous and really difficult to turn at inopportune moments.) In the end, I think i want something for extreme circumstances otherwise i want it to act like it's not there, right? Any recommends for brands that make dampers for the 1999 R850R where I can get this? Eventually, if it matters, this bike will indeed have wife on back and loaded cases everywhere.

Morning Blue7

 

That is difficult to recommend anything as I have no history with aftermarket 1100R steering dampers. There are some aftermarket that are adjustable & some that are variable in nature (not much resistance at moderate bar movement but increase resistance as the speed of input increases) 

 

The problem is that most (if not all) good aftermarket steering dampers are expensive. 

 

About all I can recommend is  trying to free your damper up (grease the pivot balls & make sure the piston/shaft slides  smoothly. 

 

Or find an aftermarket that does what you want at a price you can afford. 

 

Of just ride without one, there are a LOT of 850R/1100R/1150R riders that ride those things every day with worn out or leaked out factory dampers & live to tell about it.  You just need to be aware (& stay aware) of what c-o-u-l-d happen until you get enough miles on that motorcycle to see if headshake will be an issue. 

 

Be especially vigilant as your front tire wears or right after replacing the front tire with a new one of different brand or style.   

 

 

[Blue7]

OK. Dirtrider, thanks. I'll keep vigilant.

 

And thanks again to you all.

 

Jm

 

[Blue7]

Hello All,

 

  I wanted to get back to this forum thread after a proper tour with wife and bike completely maxed-out. Fully laden and through a pretty thorough set of riding conditions including nighttime steep dirt roads through ruts and rocks, smooth fast highways and everything in between including a bout of frozen hale, I think the 1999 r850r is now road tested and road worthy. Thank you all for the insights you gave me while I was on the road and troubleshooting in the middle of the previous tour. You are all gentlemen and much appreciated. Attached is south eastern Spain as you might well see and a west coast beach. The t-shirt illustration was made on this tour for my Barcelona moto mechanic's shop, of course featuring MY moto!:

 

Be well, gents,

Blue7 

[wbw6cos]

Glad you got things sorted.

 

Pretty cool t-shirt!

[JamesW]

Hello Blue7.  Great pictures of your '99 R850R.  I can't help but notice the side cases on your bike.  Could you tell me what brand they are and maybe where they came from?

 

There is an interesting thread running over on the fjrowners forum about head shake that's up to 14 pages long that I've been taking part in as my FJR had a deceleration front end wobble that started in at about 40mph.  This would occur if I didn't keep my hands on the handlebars when decelerating.  The bike only had about 1200 miles on the odometer when I noticed the wobble.  Many others have noticed this phenomena and the cure most folks go with is replacement of the ball bearings in the steering head with tapered roller bearings.  Then, I suspect, most just tighten up the steering head until they damp out the wobble,  In other words they, imo, don't investigate further to find the actual root cause of the wobble and instead just install tapered roller bearings that in affect become steering head dampers.  I didn't go that way.  In the end I  replaced the Metzler OEM tires with Michelin PR2 units and no more deceleration wobble, none.  D.R. in a previous post on this thread did an outstanding writeup on causes of head shake and he really emphasized the roll tires can play in this issue, good job!  On those Metzler steel belted tires the tread pattern specifically the pattern in the exact center of the tire was in the shape of a sine wave, I believe, was the main culprit.  I also became a believer in making sure you run the correct tire pressure and I have great results with 41psi front and 42psi rear which I run in my R1100RSL as well as the FJR.

 

I'm going to suggest the FJR guys come over here and check out this thread, I think, although the super forum moderator has not appreciated my input on this subject and has even threatened to close the thread.  He isn't at all tolerant of those with opinions that differ from his own and I think I'll just leave it alone as in nothing to be gained.

 

Thanks,

James - Oregon Coast (USA)

[Blue7]

JamesW, The side bag manufacturer is in Poland. A company called Holan. The Nomada Pro line. Here's a link:   https://holan.pl/en/nomada-pro-panniers/3904-2385-nomada-pro-ii-panniers-.html#/36-kolor_kufra_kufrow-natural_alu/44-capacity-31l

[JamesW]

7 hours ago, Blue7 said:

JamesW, The side bag manufacturer is in Poland. A company called Holan. The Nomada Pro line. Here's a link:   https://holan.pl/en/nomada-pro-panniers/3904-2385-nomada-pro-ii-panniers-.html#/36-kolor_kufra_kufrow-natural_alu/44-capacity-31l

 

Thanks very much for that information.  I couldn't find a set of panniers for my model on their website so I sent them a private message to see if they can help me.  I recently purchased a Dominator muffler for my bike and I believe it was made in Poland and I'm very impressed with its build quality and performance so good stuff coming from that part of the world.

 

Jim

[Blue7]

JamesW,

 

Just to be clear, I purchased the Nomad cases and mounts and locks from Holan, all the pieces are sold separately there, but my frames i used are from a German manufacturer who makes frames for my model. So, you need to find frames to mount onto if you buy those cases.

 

And by chance I also have had a Dominator muffler on my previous moto and yes, the Poles make good stuff.

 

For what it's worth,

B7

[JamesW]

Hi Blue7,

I sent Holan an e-mail to see what is available for my R1100RSL.  I've never been a fan of the OEM cases for an 1100/1150 bike.  Thanks again for your info.

[Blue7]

JamesW,

 

  I have never understood the fascination with side loading bags from BMW. They don't make a lick of sense to me. You open up the cases and stuff just spills out? They are almost unusable for any serious touring or even a quick ride to the store for some beer. I just don't get it why BMW continues to supply side loaders. Regardless, good luck getting the bags you need.

 

B7