Clunking/Thunking Front End........

brittrunyon

'92 R100GS

• Apr 27, 2012

• #1

Anybody have ideas of what could be the problem?
Listen & you will hear a noticeable "thunk", both down & up.
For me it sounds/feels like it's in the upper portion of the fork tubes.........
I can really feel it on the triple tree............not down low.............

https://vimeo.com/41179450

 

toooldtocare

Active member

• Apr 27, 2012

• #2

May be time to inspect the insides of the forks. My RS did that too until they were rebuilt.

 

brittrunyon

'92 R100GS

• Apr 27, 2012

• #3

Does this make viewing the vid of my problem easier?
<iframe src="http://player.vimeo.com/video/41179450" width="630" height="354" frameborder="0" webkitAllowFullScreen mozallowfullscreen allowFullScreen></iframe>

 

toooldtocare

Active member

• Apr 28, 2012

• #4

Not the same as my clunk. Mine did it only at the extremes.

 

4

40427

New member

• Apr 29, 2012

• #5

Almost sounds and looks like, the back end of your front fender is hitting the red crash bar ???

 

88bmwjeff

SF Bay Area

• Apr 29, 2012

• #6

Check your top plate. When they are loose, they can have a clunking sound too.

 

20774

Liaison

Staff member

• Apr 29, 2012

• #7

Get one of those mechanics stethoscope and put it at various places on the front front from the brake all the way to the top plate. Then see where the sound is really the highest.

 

kstoo

Huckleberry, Gilera &Toad

• Apr 29, 2012

• #8

Check steering head bearings for play, though I don't think so in this case.
While we're on your videos ... I love that "few pieces of toast" one!

 

brittrunyon

'92 R100GS

• Apr 29, 2012

• #9

I did the steering head bearing last Fall, before riding to The Darian Gap.
They seem OK now, tight, etc.
Glad you enjoyed the video! We had fun shooting it and coming up with inventive camera angles.
https://vimeo.com/user2721333

I ordered a stethoscope to better diagnose.

The top plate is tight.

I'm fairly busy right now, but should be able to trouble shoot some more this week.
Thanks for all the input!

 

4

40427

New member

• Apr 29, 2012

• #10

Please keep us posted on the outcome !!

 

6

68159

Simpleman

• Apr 30, 2012

• #11

That seems like an excessive amount of front dive I would check the fluid level and maybe go to a heavier weight fluid?????

 

brittrunyon

'92 R100GS

• Apr 30, 2012

• #12

I WISH I HAD TAKEN PHOTOGRAPHS!

I drained the fork oil in both right & left fork tube today.
The oil, with only 3k miles on it looked like used engine oil. With a flashlight I could see "shiny" metal particles.
The right fork tube oil actually had at least one larger piece of metal (the size of a flea) in it.
I guess this is a bad sign?

So what NOW?

1. I will pull the forks
2. Order Progressive Springs
3. Emulator ?

I want to "upgrade" the front end.
..................................................

 

Last edited: May 1, 2012

4

40427

New member

• May 1, 2012

• #13

Upgrading the suspension is like telling an engine builder to make you a fast motor. How fast do you want to go ?
How much do you want to spend.

All depends on your budget and how you use the machine IMHO.

What ever you decide , it will be a big change from stock.

 

brittrunyon

'92 R100GS

• May 1, 2012

• #14

I'm thinking the springs are "tired", and replacing with progressive springs would be a good idea. Perhaps a set of Wilbers?

As far as adding an emulator ...... Im searching the forms on the why?, what?, and how much?

How I use the machine?

I ride the forest roads of Northern New Mexico for giggles & grins, but not the really serious single track. I ride 2 up and loaded (not that one) through the Desert SW, Central America 4 times in the last 8 years.

 

tommcgee

Unfunded content provider

• May 1, 2012

• #15

I ride the same kind of roads as you. Add a vote for "I hate progressive rate springs" -- get straight rate. The Ricor Intiminator or RaceTech Emulator valves are great upgrades for damper rod suspensions. I prefer the Ricor because you don't have to futz with it as much, just drop it in and ride.

 

brittrunyon

'92 R100GS

• May 1, 2012

• #16

tommcgee said:

I ride the same kind of roads as you. Add a vote for "I hate progressive rate springs" -- get straight rate. The Ricor Intiminator or RaceTech Emulator valves are great upgrades for damper rod suspensions. I prefer the Ricor because you don't have to futz with it as much, just drop it in and ride.

Click to expand...

Thanks for the input
What does "don't have to futz with it as much" mean?

I looked at the Race Tech site:
The springs are not "progressive" with a spring rate of 80kg/mm for my weight.
The stock spring rate is .47kg/mm
I'm guessing this just means that it is a stiffer spring.
Should there still be a sag (weighted vs unweighted) of 1 to 2 inches in the front?

I'm wondering what this actually means?

 

brittrunyon

'92 R100GS

• May 21, 2012

• #17

40427 said:

Please keep us posted on the outcome !!

Click to expand...

OK, here's the update.........

It was the steering head bearings. They were a "hair" to loose.

I did rebuild the forks, there was just too many miles of 2 up & loaded. I installed Race Tech springs & Gold Valve Emulator................very nice upgrade.............

I first used "Anton's" technique on tightening the bearings, the "cluck/thunk" was still there.

Then on the second adjustment I snugged the adjuster knob a "bit" more. Maybe an inch more rotation on the adjuster knob & now all is good.

Ready to Ride!

Thanks for all the input & ideas!