Fork Conundrum

Frodad78
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TX US
1/21/2017 4:43pm
Bike: 2005 YZ125

My issues are I have harshness in the initial stroke on the front forks. When I back off on the compression the harshness dissipates but now they are too damn soft on bigger hits. Blew my left hand of the bars today on a big landing, pretty sure its because I bottomed the front so hard my wrist over rotated.

How do I resolve this?
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Frodad78
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1/21/2017 4:56pm
Note, initial harshness is mostly on smaller chop and square edged stuff. .
Monk
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1/21/2017 6:10pm
When's the last time they had a service?
1/21/2017 6:41pm
I have a similair problem and am interested as well.
Frodad78
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1/21/2017 10:32pm
Monk wrote:
When's the last time they had a service?
It's been a while, I was thinking earlier that they could probably need a refresh. I do remember having the harshness after my last rebuild, I slowly kept going softer over a long period of time.

The Shop

Monk
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1/22/2017 7:13am Edited Date/Time 1/22/2017 7:18am
Monk wrote:
When's the last time they had a service?
Frodad78 wrote:
It's been a while, I was thinking earlier that they could probably need a refresh. I do remember having the harshness after my last rebuild, I...
It's been a while, I was thinking earlier that they could probably need a refresh. I do remember having the harshness after my last rebuild, I slowly kept going softer over a long period of time.
Outside the refresh, it could be a number of things such as worn parts, bent shims, bent fork tube, etc etc. I would check and make sure your wheel and fork are in alignment first as that will effect performance. But assuming everything is good, it's going to be a valving issue. You're either going to have to buy the right tools and tackle it yourself or send it away... Adjusting clickers is not going to really help...

The cheapest route, back your compression off and add about 15-20cc of oil to control the bottoming...
Frodad78
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1/22/2017 11:12am
Monk wrote:
Outside the refresh, it could be a number of things such as worn parts, bent shims, bent fork tube, etc etc. I would check and make...
Outside the refresh, it could be a number of things such as worn parts, bent shims, bent fork tube, etc etc. I would check and make sure your wheel and fork are in alignment first as that will effect performance. But assuming everything is good, it's going to be a valving issue. You're either going to have to buy the right tools and tackle it yourself or send it away... Adjusting clickers is not going to really help...

The cheapest route, back your compression off and add about 15-20cc of oil to control the bottoming...
I was wondering about Valving, I doubt the internals are worn, I always have the forks done by a local guy. Last time I mentioned my issues to him he mentioned a re valve.

The fork oil is an idea to consider.

Can someone explain what exactly a revalve job does? For instance would an aftermarket product like Gold Valves help?

Thanks!

coastie44
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NorCal, CA US
1/22/2017 12:17pm Edited Date/Time 1/22/2017 12:24pm
Frodad78 wrote:
I was wondering about Valving, I doubt the internals are worn, I always have the forks done by a local guy. Last time I mentioned my...
I was wondering about Valving, I doubt the internals are worn, I always have the forks done by a local guy. Last time I mentioned my issues to him he mentioned a re valve.

The fork oil is an idea to consider.

Can someone explain what exactly a revalve job does? For instance would an aftermarket product like Gold Valves help?

Thanks!

"The cheapest route, back your compression off and add about 15-20cc of oil to control the bottoming."

This was good advice. It's super easy to do and takes less than 30 min total. I would start with 10cc with the clickers at your current spot. Try that. You should feel less bottoming. Then add another 5cc at a time. I probably wouldn't add more than 20cc unless they were set up with really low oil level as 20cc is enough to make a good difference.

A "revalve" at it's simplest is to adjust the size, thickness, and number of shims that control how the oil flows in the forks. They are basically small thin washers that block oil from coming out of a small orifice. They bend more when the oil has more pressure against them.

It doesn't take much change of the shims to make a big change in the feel.

A revalve will also include setting the forks with recommended oil volume, but it is extremely common to "tune" that yourself by adding/removing up to 20cc or so.

"Gold valves" are a product that replaces the stock valves in the suspension. The "valves" are just the item that has the holes that oil flows through. The size, placement of the ports are a huge part of the feel and tuners have to learn how each new fork's stock valve affects the overall action. Race tech simplified this a little by producing and replacing stock valves with their own because that takes one huge variable out of the equation and makes it easier to find a good setting for a wide range of riders.
T981
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NL
1/22/2017 12:23pm
Maybe your lower tripple clamps are overtightened? This will squeeze your fork tubes, resulting in a harsh feeling at the beginning of the stroke.
Frodad78
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1/22/2017 6:48pm
T981 wrote:
Maybe your lower tripple clamps are overtightened? This will squeeze your fork tubes, resulting in a harsh feeling at the beginning of the stroke.
No thankfully I'm OCD and use a torque wrench on everything. I know these with this particular year and model most tuners till me Yamaha "Missed the Mark" With the forks, its the only year the 125 had them and basically the springs are short. A general fix was to put 10mm spacer in the forks because you could literally here the forks top out and the springs rattle in the tubes it was crazy.
Frodad78
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1/22/2017 6:53pm
coastie44 wrote:
"The cheapest route, back your compression off and add about 15-20cc of oil to control the bottoming." This was good advice. It's super easy to do...
"The cheapest route, back your compression off and add about 15-20cc of oil to control the bottoming."

This was good advice. It's super easy to do and takes less than 30 min total. I would start with 10cc with the clickers at your current spot. Try that. You should feel less bottoming. Then add another 5cc at a time. I probably wouldn't add more than 20cc unless they were set up with really low oil level as 20cc is enough to make a good difference.

A "revalve" at it's simplest is to adjust the size, thickness, and number of shims that control how the oil flows in the forks. They are basically small thin washers that block oil from coming out of a small orifice. They bend more when the oil has more pressure against them.

It doesn't take much change of the shims to make a big change in the feel.

A revalve will also include setting the forks with recommended oil volume, but it is extremely common to "tune" that yourself by adding/removing up to 20cc or so.

"Gold valves" are a product that replaces the stock valves in the suspension. The "valves" are just the item that has the holes that oil flows through. The size, placement of the ports are a huge part of the feel and tuners have to learn how each new fork's stock valve affects the overall action. Race tech simplified this a little by producing and replacing stock valves with their own because that takes one huge variable out of the equation and makes it easier to find a good setting for a wide range of riders.
Thanks for the Info, I learned something there! I'm going to give Race Tech a call tomorrow and see what kind of plan they have. Their spring rate calculator says I need to be 1 heavier spring size up from stock, I feel like the faster I've been going the more issues I seem to find with the forks and handling. I guess I'm wondering how much of a difference a revalve/spring would make. Based on what you told me I imagine it could be very noticeable.
captmoto
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Rancho Cucamonga, CA US
1/22/2017 10:25pm
Race Tech or any other reputable shop is going to make a noticeable difference if you are honest with them. There is a lot unsaid that could affect how your suspension works. Your size and speed, condition of your fork internals and what not. Whoever does your suspension, you need to be sure to tell them you are getting faster. You also want to do your shock at the same time to have good front/rear balance. Even if you are only changing springs you might want to do the rear spring too.
tempura
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JP
1/22/2017 10:56pm
I'd also start off adding some oil. It won't cost you much and is easy to do. Adding oil sounds like it could remedy your problem.
Also remember, any fairly large changes to the front will effect the back and fronts ability to work together.
Frodad78
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1/23/2017 4:34am
Great info guys, I'm going to play with some oil levels and see If I can get it to behave. Thanks!
KooyaKooya
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Salt Lake City, UT US
1/23/2017 4:18pm
If I were you, I would start by reducing as much stiction as possible before messing with valving or oil height. It's amazing how much harshness stiction can add.

1) Run SKF Green seals.
2) Run fresh OEM bushings (Inner and outer. The copper that is laid onto the non-teflon side wears off, causing the bushings to fit too loosely, which causes them tilt during fork action, causing stiction).
3) Run Honda HP 5 weight oil (It's the slipperiest stuff I've tried, and it's cheap to boot)
4) While you've got them apart to change the seals and stuff, check the tubes for runout. They are probably fine as it's hard to bend 'em, but it's a good thing to check off the list.
5) Be crazy OCD when reassembling the front end. The best method I've found for lining everything up is the method where you remove the fork caps and sink the forks through their travel with everything really loose so that the forks can fall into perfect parallel. In brief form, my method is to mount up the forks to the desired height using only the lower triple clamps to hold them in place. Install the wheel and axle tightening only the nut-side lug, and the nut. Then with everything else real loosey goosey (including a screw driver wedged into the non-nut fork lug to hold it open so it can slide on the axle, the upper triple clamp bolts loose and the steering nut loose so the upper clamps can swivel into alignment with the lower), I'll pull the caps out and sink the forks down till they bottom out and then start tightening things up. You want to take caution not to tweak the alignment as you tighten everything back up. For example, don't hold the wheel between your knees as you torque down the steering nut as this can twist everything up. Finally, I run pretty light torque values on my lower clamps to ensure there's not pinching going on, even lower than the manual suggests.

In my experience, these things pretty much solved my small bump harshness. Good luck.
Monk
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1/28/2017 5:01pm
coastie44 wrote:
"The cheapest route, back your compression off and add about 15-20cc of oil to control the bottoming." This was good advice. It's super easy to do...
"The cheapest route, back your compression off and add about 15-20cc of oil to control the bottoming."

This was good advice. It's super easy to do and takes less than 30 min total. I would start with 10cc with the clickers at your current spot. Try that. You should feel less bottoming. Then add another 5cc at a time. I probably wouldn't add more than 20cc unless they were set up with really low oil level as 20cc is enough to make a good difference.

A "revalve" at it's simplest is to adjust the size, thickness, and number of shims that control how the oil flows in the forks. They are basically small thin washers that block oil from coming out of a small orifice. They bend more when the oil has more pressure against them.

It doesn't take much change of the shims to make a big change in the feel.

A revalve will also include setting the forks with recommended oil volume, but it is extremely common to "tune" that yourself by adding/removing up to 20cc or so.

"Gold valves" are a product that replaces the stock valves in the suspension. The "valves" are just the item that has the holes that oil flows through. The size, placement of the ports are a huge part of the feel and tuners have to learn how each new fork's stock valve affects the overall action. Race tech simplified this a little by producing and replacing stock valves with their own because that takes one huge variable out of the equation and makes it easier to find a good setting for a wide range of riders.
Frodad78 wrote:
Thanks for the Info, I learned something there! I'm going to give Race Tech a call tomorrow and see what kind of plan they have. Their...
Thanks for the Info, I learned something there! I'm going to give Race Tech a call tomorrow and see what kind of plan they have. Their spring rate calculator says I need to be 1 heavier spring size up from stock, I feel like the faster I've been going the more issues I seem to find with the forks and handling. I guess I'm wondering how much of a difference a revalve/spring would make. Based on what you told me I imagine it could be very noticeable.
1 up on the spring rate won't make a difference, valving will...
Jack_Wagon
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Conyers, GA US
1/30/2017 5:31am
Those 05 YAMAHA forks had an issue with the inner chambers staying primed. On hard landings they would pump fluid out of the inner chambers and create the feeling you are having. Some of the big suspension companies offered a spacer that cured the problem.
Frodad78
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1/30/2017 11:45am
Jack_Wagon wrote:
Those 05 YAMAHA forks had an issue with the inner chambers staying primed. On hard landings they would pump fluid out of the inner chambers and...
Those 05 YAMAHA forks had an issue with the inner chambers staying primed. On hard landings they would pump fluid out of the inner chambers and create the feeling you are having. Some of the big suspension companies offered a spacer that cured the problem.
We already did the spacers, thanks for the heads up anyways though!

So I added 10ml of oil to each fork and went a little stiffer on the compression. Had a good practice day yesterday, I was able to be way more aggressive and really slam through this set of rollers without feeling like the forks were mush so I think we made some progress here.

My only complaint now is that I'm still getting headshake on jump downsides and heavy braking. I like to get over the front of the bike so I think maybe dropping my tubes in the clamps might solve the issue. My Sag is right at 105.

Thanks again for all your input, It felt good to be hauling yesterday with confidence in the front end!
Monk
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1/30/2017 11:49am
Jack_Wagon wrote:
Those 05 YAMAHA forks had an issue with the inner chambers staying primed. On hard landings they would pump fluid out of the inner chambers and...
Those 05 YAMAHA forks had an issue with the inner chambers staying primed. On hard landings they would pump fluid out of the inner chambers and create the feeling you are having. Some of the big suspension companies offered a spacer that cured the problem.
Frodad78 wrote:
We already did the spacers, thanks for the heads up anyways though! So I added 10ml of oil to each fork and went a little stiffer...
We already did the spacers, thanks for the heads up anyways though!

So I added 10ml of oil to each fork and went a little stiffer on the compression. Had a good practice day yesterday, I was able to be way more aggressive and really slam through this set of rollers without feeling like the forks were mush so I think we made some progress here.

My only complaint now is that I'm still getting headshake on jump downsides and heavy braking. I like to get over the front of the bike so I think maybe dropping my tubes in the clamps might solve the issue. My Sag is right at 105.

Thanks again for all your input, It felt good to be hauling yesterday with confidence in the front end!
Slide the forks down or tighten you steering head nut slightly...
Frodad78
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1/30/2017 11:55am
Jack_Wagon wrote:
Those 05 YAMAHA forks had an issue with the inner chambers staying primed. On hard landings they would pump fluid out of the inner chambers and...
Those 05 YAMAHA forks had an issue with the inner chambers staying primed. On hard landings they would pump fluid out of the inner chambers and create the feeling you are having. Some of the big suspension companies offered a spacer that cured the problem.
Frodad78 wrote:
We already did the spacers, thanks for the heads up anyways though! So I added 10ml of oil to each fork and went a little stiffer...
We already did the spacers, thanks for the heads up anyways though!

So I added 10ml of oil to each fork and went a little stiffer on the compression. Had a good practice day yesterday, I was able to be way more aggressive and really slam through this set of rollers without feeling like the forks were mush so I think we made some progress here.

My only complaint now is that I'm still getting headshake on jump downsides and heavy braking. I like to get over the front of the bike so I think maybe dropping my tubes in the clamps might solve the issue. My Sag is right at 105.

Thanks again for all your input, It felt good to be hauling yesterday with confidence in the front end!
Monk wrote:
Slide the forks down or tighten you steering head nut slightly...
Will do man I'll let you guys know how it goes!
mwssquad827
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Twin Falls, ID US
1/31/2017 4:18am
Find some SSS and problem is solved!!
Frodad78
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TX US
1/31/2017 8:39am
Dude I know, If I ever find a pair that's priced reasonably I'll be all over it!
mwssquad827
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Twin Falls, ID US
1/31/2017 9:14am
Dude me and a buddy have bought complete front ends (brakes,wheel, spacers, triple clamps, everything to just swap over. We have bought like 3 the last year, all for under $250. They are out there you just have to look and talk to people
Monk
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CA
1/31/2017 9:30am
For what it would cost to buy SSS suspension, a revalve will go alot farther...
Frodad78
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2154
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1/11/2012
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TX US
1/31/2017 10:15am
Dude me and a buddy have bought complete front ends (brakes,wheel, spacers, triple clamps, everything to just swap over. We have bought like 3 the last...
Dude me and a buddy have bought complete front ends (brakes,wheel, spacers, triple clamps, everything to just swap over. We have bought like 3 the last year, all for under $250. They are out there you just have to look and talk to people
Damn thats impressive, Around here they go for at least 500. Then again the moto community in North Texas is pretty large and strong, maybe its the market.
Frodad78
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TX US
2/2/2017 7:43am
Update, Dropped the forks in the tubes and noticed the front was a little sloppy on the stand. Gave the steering nut a tap and it seemed to slow it down a bit. No more headshake!

Thanks everyone for all your input and information!

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