Oscillating Forks

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Holysmoke
Posts: 32
Joined: Sun Nov 23, 2014 9:14 am

Oscillating Forks

Post by Holysmoke »

Next thing to dial in on my 1978 R100S

I'm getting a front tire bounce above 75 mph and my front end is very spongy. Racetrch can set me up with their gold cartridge emulator, spring and oil for $400. The forks have to be 36mm. Are my forks 36mm? Is this a good setup for this bike?

Thanks in advance,
Ron
Mal S7
Posts: 661
Joined: Thu Aug 05, 2010 5:26 am

Re: Oscillating Forks

Post by Mal S7 »

Hi
You will read different opinions on the Emulators. Race-tech springs are also a lot stiffer than stock and reduce your fork travel. If you ride mostly good roads that might not be a worry. Aftermarket rear shocks also have less travel than stock. I fitted their emulators with sonic springs and like the result, but setting it up right is a test of patience. I will try to find you the link to previous discussions.
Yes your forks would be 36mm

You should first try getting your front end sorted out with the stock set up. It could be steering head bearings, or bent or misaligned and or stiction, wrong preload, fork oil, worn components. Have you pulled it apart and inspected it?

Emulator thread- viewtopic.php?f=1&t=2598
Holysmoke
Posts: 32
Joined: Sun Nov 23, 2014 9:14 am

Re: Oscillating Forks

Post by Holysmoke »

Mal S7 wrote:Hi
You will read different opinions on the Emulators. Race-tech springs are also a lot stiffer than stock and reduce your fork travel. If you ride mostly good roads that might not be a worry. Aftermarket rear shocks also have less travel than stock. I fitted their emulators with sonic springs and like the result, but setting it up right is a test of patience. I will try to find you the link to previous discussions.
Yes your forks would be 36mm

You should first try getting your front end sorted out with the stock set up. It could be steering head bearings, or bent or misaligned and or stiction, wrong preload, fork oil, worn components. Have you pulled it apart and inspected it?

Emulator thread- viewtopic.php?f=1&t=2598
Good advise. No, I haven't torn them down yet. I was trying to have parts in hand beforehand, but that might not work. I'll start tearing into it. Do the springs wear out? Good thread on the emulators and Progressives
Last edited by Holysmoke on Mon May 04, 2015 4:45 pm, edited 1 time in total.
Kurt in S.A.
Posts: 1647
Joined: Tue Aug 03, 2010 12:08 pm

Re: Oscillating Forks

Post by Kurt in S.A. »

What would tire balancing and changing the front fork oil cost? Seems to me I'd try that first before dropping a bunch of cash.

Kurt in S.A.
ME 109
Posts: 7307
Joined: Tue Aug 03, 2010 3:00 am
Location: Albury, Australia

Re: Oscillating Forks

Post by ME 109 »

Stock works fine..........when all is in order.
As already pointed out, try and fix what you have.
A bouncing front end is more likely to be a tyre mounting/balance issue firstly, followed by fork oil and stiction.
There is only one way to assess fork alignment,
pull the whole front end apart.
Perfectly straight fork legs, and perfectly straight triple tree are the base on which to build.
Lord of the Bings
Holysmoke
Posts: 32
Joined: Sun Nov 23, 2014 9:14 am

Re: Oscillating Forks

Post by Holysmoke »

Kurt in S.A. wrote:What would tire balancing and changing the front fork oil cost? Seems to me I'd try that first before dropping a bunch of cash.

Kurt in S.A.
Again, good advise. I'm going to replace the seals next week. I'll balance the tire too. I've never noticed a difference after tire balancing before
Kurt in S.A.
Posts: 1647
Joined: Tue Aug 03, 2010 12:08 pm

Re: Oscillating Forks

Post by Kurt in S.A. »

Be sure and check the tire mold lines relative to the rim all the way around. If a tire doesn't seat correctly, it will create handling problems. It's easy to spot.

Kurt in S.A.
Major Softie
Posts: 8900
Joined: Tue Aug 03, 2010 1:46 pm

Re: Oscillating Forks

Post by Major Softie »

Good call, Kurt. Usually it's tubeless tires that have that issue, but I'm sure it could happen with a tube-type as well.
MS - out
ME 109
Posts: 7307
Joined: Tue Aug 03, 2010 3:00 am
Location: Albury, Australia

Re: Oscillating Forks

Post by ME 109 »

Holysmoke if your rear tyre has flattened off, that could account for half of your handling problems.
Lord of the Bings
Holysmoke
Posts: 32
Joined: Sun Nov 23, 2014 9:14 am

Re: Oscillating Forks

Post by Holysmoke »

ME 109 wrote:Holysmoke if your rear tyre has flattened off, that could account for half of your handling problems.
30 Pounds front and rear. I'll Check the bead
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