A visit to KFG Racing (new owner of GP Suspension)

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I float the rear shock DIY idea again...

Anyone have clues as to tool investment vs return might be?
Probably on the order of changing tires Don. A couple special tools, access to new seals, oil and a nitrogen cylinder w/gauge set. Now if you can get some buddies to go in and split costs 4 or 5 ways, might be doable.

Just guessing...

--G

 
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KFG will be at the Seattle IMS Show with a few extra sets of spring guides (below) for sale, if anyone has already done the GP suspension uprade prior to their update.

WP_20121208_016.jpg


 
I float the rear shock DIY idea again...

Anyone have clues as to tool investment vs return might be?
Probably on the order of changing tires Don. A couple special tools, access to new seals, oil and a nitrogen cylinder w/gauge set. Now if you can get some buddies to go in and split costs 4 or 5 ways, might be doable.

Just guessing...

--G
 
KFG will be at the Seattle IMS Show with a few extra sets of spring guides (below) for sale, if anyone has already done the GP suspension uprade prior to their update.
Good to know Hudson, thanks. I'll be picking up a pair for the next fork fluid change.

--G

 
KFG will be at the Seattle IMS Show with a few extra sets of spring guides (below) for sale, if anyone has already done the GP suspension uprade prior to their update.
Good to know Hudson, thanks. I'll be picking up a pair for the next fork fluid change.

--G
G - they go on the top end of the springs then the washer on top of the guide and then the spacer and nut. If you have room on your preload (I think it is 2 lines) then you may not have to cut the space between the spring and the top caps. We had room on Hudson's when we rebuilt his forks so we left the spacers length alone.

 
Last edited by a moderator:
KFG will be at the Seattle IMS Show with a few extra sets of spring guides (below) for sale, if anyone has already done the GP suspension uprade prior to their update.
Good to know Hudson, thanks. I'll be picking up a pair for the next fork fluid change.

--G
G - they go on the top end of the springs then the washer on top of the guide and then the spacer and nut. If you have room on your preload (I think it is 2 lines) then you may not have to cut the space between the spring and the top caps. We had room on Hudson's when we rebuilt his forks so we left the spacers length alone.
Thanks Auburn. I may not have enough room on the preload adjustment then. I'll talk to y'all more in depth about Hudson's install.

--G

 
Thursday afternoon KFG calls and says you might want to come by and look at the shims on your shock. I said I would stop by after work on my way home.

A quick check of my records for the bike and GP did my forks and sold me the Penske shock on 10/1/08 with 5,800 miles on the bike. I had a note in my records telling me to have the shock serviceed every 20,000 miles by Dave Hodges.

You can imagine my shock when I checked the records and see I have ridden 27,870 miles since I put the shock on. OOPS!

I knew something was up when about 5,000 miles ago I had to add a couple of clicks of high speed compression because the shock was bottoming on the FS-90 road behind Mt. St. Helens in places it didn't use to. But I did not have time to get it rebuilt before our trip to Arizona and Utah in September.

This picture is the slow speed shims: You will see the scuffs and the black marks showing the corrosion and wear. These shims are stainless steel.

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A close up of two of the shims:

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This picture is not very good but shows more of the same corrosion on the high speed shim stack and they will need to be replaced. The same black marks and corrsion can be seen, (although not very well in this picture) since all I had was my phone with me to take the pictures. Which cost about 2 hours more shop time. Totally my fault for going too far between service intervals.

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GP took a series of pictures when taking the shock apart and will send them to me when they get a chance. I'll post them up here so you all can see this shock with a know number of miles on it.

To put the wear in prospective for those that have not ridden with me, I typically ride two up 95% of the time. I have towed the trailer about 13,000 miles of time since the shock was installed on the bike. I typically go for as much twisty road as I can find when going places. I do tend to push the pace in the twisties and have occaisionally done many hours of near triple digits when on open remote highways here in the west. I avoid the interstates as much as possible. I would say that <20% of the miles are on interstates.

As with anything, your wear will very on your shock.

I am pretty certain the 20,000 mile limit Dave Hodges advised me of is a maximum limit for the way my bike is set up and ridden. I will probably service it each year, because I have the time in the winter to do so, and because I am riding with a passenger most of the time. And we ride near the physical limits of the machine on roads that are not in the greatest of shape. Meaning that we are frequenlty leaned over to the point where a bump could cause hard parts to drag and affect traction. It does not mean I am at very high speeds leaned over. It does mean I may be doing a downhill decreasing radius turn with a pretty good crown signed at 20 mph and going through the corner at 40 mph. There is not a lot of room left for the suspension that is not performing properly.

The golden rule when riding with a passenger is never put the passenger at risk and I don't want to risk a preventable mechanical failure just to save $150.

More to come when I get the other pictures.

 
Barry handed my rebuilt ohlins to me at the show with some pix. not as bad as bryans, but it still needed service after 15k of use. The amazing thing was that he did not replace the spring with the next size up. just servicing the shock allowed him to back down 10 clicks on the preload. I'm going to try with the same spring, which will save me some dough.

 
Barry handed my rebuilt ohlins to me at the show with some pix. not as bad as bryans, but it still needed service after 15k of use. The amazing thing was that he did not replace the spring with the next size up. just servicing the shock allowed him to back down 10 clicks on the preload. I'm going to try with the same spring, which will save me some dough.
I'm assuming you have a hydraulic preload adjuster otherwise 10 clicks on the preload makes no sense. They may have compressed the spring more by threading the preload adjuster down further onto the spring thereby "reseting" the preload adjuster and giving you more range of preload adjustment.

It would be interesting to know if they took a measurement of the spring length under compression when you sent the spring in and then matched that measurement when the shock was reassembled with the preload adjuster backed off.

Have you checked your sag measurements yet? If the rider sag under normal loads is correct and you have some free sag then the spring rate for your bike is correct and you will not need to change the spring.

 
Barry handed my rebuilt ohlins to me at the show with some pix. not as bad as bryans, but it still needed service after 15k of use. The amazing thing was that he did not replace the spring with the next size up. just servicing the shock allowed him to back down 10 clicks on the preload. I'm going to try with the same spring, which will save me some dough.
I'm assuming you have a hydraulic preload adjuster otherwise 10 clicks on the preload makes no sense. They may have compressed the spring more by threading the preload adjuster down further onto the spring thereby "reseting" the preload adjuster and giving you more range of preload adjustment.

It would be interesting to know if they took a measurement of the spring length under compression when you sent the spring in and then matched that measurement when the shock was reassembled with the preload adjuster backed off.

Have you checked your sag measurements yet? If the rider sag under normal loads is correct and you have some free sag then the spring rate for your bike is correct and you will not need to change the spring.
Yes you are correct he has a hydraulic preload adjuster on his ohlins shock. We'll be putting the shock on tomorrow.

 
I talked to Barry about Dave's shock and they added more preload by tighting the collar on the spring by 10mm and he can add more preload with the remote adjuster.

 
Very interesting pictures.

I think that the small amount of wear that can be seen on the low speed shims is probably less alarming than the corrosion spots. With that corrosion being so localized, I don't think this is being caused by any sort of suspension fluid oxidation, as you would expect that to be far more uniform in nature. More likely to be some sort of external contamination (water?) and that water stays separated from the oil. If this were true, then the mileage between services might be less important than the environment the shock has been run in. Maybe the "fair weather" riders would expect less of that contamination than the PNW rain riders?

I also find it interesting that the "stainless steel" corrodes so heavily. Must be a low grade of stainless? But that may be required to get the flexibility properties they need for those shims.

 
Wife keeps on pestering me....What do you want for Christmas! So with just a few hours to spare, last night I signed up for the group buy - fork upgrade given that my bike has ~34k without a service. Too pricey to do all at once, so hope to get the rear upgraded later in the year. Crossing fingers it is a quick turn-around time from time I hand off the forks. Thanks for all the info folks, Fontanaman's review a couple of years back sealed the deal for me.

 
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