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Tank slapper bent my rear brake lever
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egleaves Offline
1st Service Completed

Sacramento, CA
Posts: 138
Joined: Sep 2017
Post: #11
RE: Tank slapper bent my rear brake lever
I’ve read of it happening for a few common reasons:

Coming down from a wheelie
Bad head bearings
Bent rim
Tire out of balance
Sudden steering input

My tire is suspect #1 , but it seems really strange that it happened at relatively low speed, while decelerating, and under light braking. Basically everything you’re supposed to do in order to mitigate the wobble is what I was already doing. Still trying to figure out why it happened. I’m sure the bald front tire wasn’t helping, but I have a hard time believing it was the cause in this case.

2014 CB1100 Standard
04-23-2018 03:22 PM
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Lord Popgun Offline
I find your lack of RLETs disturbing

Virginia Beach
Posts: 10,442
Joined: Apr 2013
Post: #12
RE: Tank slapper bent my rear brake lever
I just took a look at my rear brake and I would not recommend kicking it back into position. You could bend the pivot mount or maybe crack the lever and not be able to see it. Looking at mine there seems to be a place it could crack and you not see it. Hard to tell.

I would remove it and bend it and examine it closely before re-installing.
I’d examine the switch and linkage too as you never know when a big shock occurs.

If you come to a fork in the road, take it!
2013 CB1100
2012 ST1300
Holder of the CB1100Forum Secret Decoder Ring
04-23-2018 03:29 PM
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egleaves Offline
1st Service Completed

Sacramento, CA
Posts: 138
Joined: Sep 2017
Post: #13
RE: Tank slapper bent my rear brake lever
(04-23-2018 03:29 PM)popgun Wrote:  I just took a look at my rear brake and I would not recommend kicking it back into position. You could bend the pivot mount or maybe crack the lever and not be able to see it. Looking at mine there seems to be a place it could crack and you not see it. Hard to tell.

I would remove it and bend it and examine it closely before re-installing.
I’d examine the switch and linkage too as you never know when a big shock occurs.

Thanks, popgun. That's exactly what I was wondering about. I won't try to bend it back until I get home and can detach it.

2014 CB1100 Standard
04-23-2018 03:37 PM
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jtopiso Offline
Running Like a Top

Spain
Posts: 431
Joined: Nov 2017
Post: #14
RE: Tank slapper bent my rear brake lever
(04-23-2018 03:37 PM)egleaves Wrote:  Thanks, popgun. That's exactly what I was wondering about. I won't try to bend it back until I get home and can detach it.

I assume it is not made of aluminium. If it is, don't even try to bend it back: it will be brittle and unsafe to use even if you get it to look good.

If it is steel, probably you'll be ok, unless you can find some cracks.
04-24-2018 12:46 AM
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Dave Offline
High Mileage

San Diego, ca
Posts: 934
Joined: Jan 2014
Post: #15
RE: Tank slapper bent my rear brake lever
Did your front tire wear unevenly (like mine did), with high and low spots on the sides? If your answer is yes, then I suspect the tire caused the wobble. My CB1100 started to head shake when the tire wore like this, and I replaced it. I switched to a different brand (can't remember off the top of my head right now) but the head shake completely went away, and the new tire is wearing much better (I'm on the third front tire now). A friend of mine crashed his CB750 back in 1981 because of unexpected head shake. Luckily he survived, but he sold the bike immediately.
04-24-2018 07:30 AM
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jtopiso Offline
Running Like a Top

Spain
Posts: 431
Joined: Nov 2017
Post: #16
RE: Tank slapper bent my rear brake lever
(04-23-2018 10:26 AM)egleaves Wrote:  I'm still trying to replay the whole thing in my head in the hope that I can determine the cause of the wobble. The bike has never done that, and aside from cars ahead and behind me conditions were pretty favorable.

I am trying to think on the causes:

-worn tyre means smaller tyre radiuis, so smaller steering trail.
-braking means bike dives, so lower trail too.

Still, I'd say this would mean the bike isn't as stable as it could be, but is that enough to cause a tank slapper... :-? I wouldn't think so!

Check your pressures (again: affect your tyre radius->steering trail), and check your suspension preload settings (rake -nose down attitude- will decrease trail too).

And, if you find the root cause, please let us know!
04-24-2018 08:08 AM
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The ferret Offline
Forum Moderator

Ohio
Posts: 31,282
Joined: Apr 2013
Post: #17
RE: Tank slapper bent my rear brake lever
Just out of curiosity, when you slowed down to 50 mph you didn't sit up and let go of the bars momentarily did you?

.
Defender of the Realm
2014 DLX (the pleasure horse)
2021 NC750X DCT (Angry Bird)
04-24-2018 08:31 AM
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egleaves Offline
1st Service Completed

Sacramento, CA
Posts: 138
Joined: Sep 2017
Post: #18
RE: Tank slapper bent my rear brake lever
(04-23-2018 10:33 AM)chync Wrote:  Wow. Have you made any mods to your front end? Or raised the rear? I thought the rake on the cb1100 was long enough to make a tank slapper very unlikely.


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(04-24-2018 08:31 AM)The ferret Wrote:  Just out of curiosity, when you slowed down to 50 mph you didn't sit up and let go of the bars momentarily did you?

I had a proper grip on the bars…..not too tight, firmly positioned, elbows bent slightly. Good thing too, or I don’t think I would have recovered it.

I checked the pressure this morning and it was down to about 27-28, so I brought it back up to ~35psi. It seems like I lose about 1 or 2 psi per month and have to top it off again. I do believe that more frequent checks are in order.

(04-24-2018 07:30 AM)Dave Wrote:  Did your front tire wear unevenly (like mine did), with high and low spots on the sides? If your answer is yes, then I suspect the tire caused the wobble. My CB1100 started to head shake when the tire wore like this, and I replaced it. I switched to a different brand (can't remember off the top of my head right now) but the head shake completely went away, and the new tire is wearing much better (I'm on the third front tire now). A friend of mine crashed his CB750 back in 1981 because of unexpected head shake. Luckily he survived, but he sold the bike immediately.

No scalloping, if that's what you mean. The profile is evenly bald out to the chicken strips.

2014 CB1100 Standard
(This post was last modified: 04-24-2018 09:41 AM by egleaves.)
04-24-2018 09:40 AM
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VLJ Offline
High Mileage

California
Posts: 905
Joined: Sep 2017
Post: #19
RE: Tank slapper bent my rear brake lever
Quote:The profile is evenly bald out to the chicken strips.

The same could be said of most CB1100 riders.

Big Grin
04-24-2018 10:47 AM
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EmptySea Offline
Lives On Two Wheels

Chicagoland, USA
Posts: 7,004
Joined: Jun 2013
Post: #20
RE: Tank slapper bent my rear brake lever
What tires are you running?

MTC

"If you can’t go home again, at least you can enjoy the ride” — Peter Egan


2013 CB1100 non-abs
2013 CB1100 abs
04-24-2018 10:58 AM
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