Reworking forks ...

Enough blah blah blah ... so how does it work?  

I went out on a 20 minute test ride and hit every bump I could find.  

I am super happy with the results!!

The jolt/jarring is dramatically reduced.  If you drive over a brick at 45 mph you'll still get a jolt, but normal-ish road imperfections don't have the harsh impact now.

In one turn there is a ~1 inch pavement ripple, just floated over that, no jolt, no wiggle, just absorbed it.  

And how much did this costs?
$6 usd - oil
$7.12 usd - shims

$13.12 total!!  

Well ... there were tools ... and the GRiSO stand.

But the fork specific tools:
$15 - ebay fork spring compressor thing
$20 - Motion Pro damping rod pull up thing (guys on youtube are using a zip tie)

I already had the impact wrench, and the vice soft jaws.  The $15 long allen wrench set, I'll call that generic tool.

So if I had paid a suspension shop $250-$350 for a suspension revalve, I would have been happy with these results.  

So ... what change did what?  I did 3 things ...
1. Different compression stack
2. Lighter weight oil
3. Less oil in the forks

I feel it is a combo of #2 & #1.  And the oil the left fork was super thick ... so #2 might be the biggest difference ... don't know.

But Round 1 was a major success!!  

Actually, not sure I need a Round II.   Will hopefully get some more rides in this week and test some more.

Winner indeed!

Thanks

A good write up.

Picking up where Usedtobefast left off.

The OEM rebound stack is;

17 x 0.10
17 x 0.10
17 x 0.10
17 x 0.15
10 x 0.2
10 x 0.2

I have decided to replace the valves with Racetech Gold valves and use the spreadsheets /calculations they provide for the shim stacks. In talking to the Racetech technical department when I found they don't have the GRiSO in their system, he said 'we can roughly calculate a set up and adjust from there'

So using the 2006 Suzuki GSXR 750 to get into the system and then added 70 lbs to my rider weight, ( 175 lbs ), to compensate for the weight difference of the bikes ( roughly 420 lbs to 490 lbs ).

These are the baseline shim sets

Compression;

17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.10
15 x 0.10
13 x 0.10
11 x 0.10
 9 x 0.15

Rebound

17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
15 x 0.10
13 x 0.15
11 x 0.15
 9 x 0.30

A 5 weight oil & air gap of 120 mm recommended. However I have changed out the springs, so the air gap may need some fiddling with.

Cool! You doing the work yourself? Or having a suspension shop/person do it? Seems like a lot of 17mm shims! But then the racetech valves supposedly flow more oil ... so would make sense to need more shims.

Hope it turns out great.

Found a suspension guy who doesn't mind me looking over his shoulder & buying the parts.

Nobleswood wrote:

Found a suspension guy who doesn't mind me looking over his shoulder & buying the parts.

Let us know how it all works out. I'd like to get my forks done as well, and I'm not that far away, 'bout 100 miles. I installed the Race Tech valves in my Blackbird a long time ago. It wasn't difficult, but a bit tedious. Now my eyes aren't as good, and my stubby fat fingers aren't quite as nimble.

I will !
Are you going to be at the ‘Garage Brewed’ event in Cincy on 2/8 ?

Yes I will. I'm actually hosting a bunch of fellow CBXers that weekend, and we'll all be there. We call it our PMS party (Parked Motorcycle Syndrome).

Look for a custom Kawasaki in orange/rootbeer w/ single sided swinger. A friend of mine built it.

Nobleswood wrote:

Found a suspension guy who doesn't mind me looking over his shoulder & buying the parts.

Hey, how did your forks turn out? Did you get it done before coronavirus set in?

The whole experience went well; Jakes a good guy & didn’t mind a gearhead learning. Thanks to you pointing out what other bikes the Showa's were on I could get the parts ordered.

I’ve only had the bike out twice now & once for a real ride. The result; the front end seems to just comply with road. You know what’s under the tyre but it’s not unsettling the bike. As this is the best set up suspension I’ve had, I can at the moment only say what it’s not doing. Which is odd. Over the summer I’ll get to know & understand it better.

All in all I’m pleased. So pleased that I bought the same front end set up that I’m going to instal on my V11 Sport, when I can get back to earning some money.

As there's a few threads on suspension mods going on at the moment, thought I'd add something to this one as Usedtobefast's comprehensive write up helped me with some actual nuts & bolt details.

Last year due to Covid I didn't ride much & its only now that I'm spending time on the bike.

Without a doubt this one of the best use of money in my opinion. I just got in from a 6 hour ride around some twisty roads that are new to me. The bike feels more planted, better balanced, it's not that my confidence has gone up in the corners (yet) but that I don't get those small slips or running wide incidents. And my chicken strips are diminishing.

Strangely the bike doesn't tire me out as much as it used to. I'm not as sore after a ride.

The high speed bumps need a bit more work but still a good beginning.

Nobleswood wrote:

As there's a few threads on suspension mods going on at the moment, thought I'd add something to this one as Usedtobefast's comprehensive write up helped me with some actual nuts & bolt details.

This thread has been a good read, and a tribute to Usedtobefast  

I’ve agreed to (soon) hand mine over to Maxton for them to perform their magic, front and rear  

Nobleswood wrote:

Last year due to Covid I didn't ride much & its only now that I'm spending time on the bike.

Without a doubt this one of the best use of money in my opinion.

Snap!  A really difficult time.  My recent purchase of the GRiSO was my way of addressing a problem by treating myself, with my first MG.

Excellence in suspension is so misunderstood and undervalued by so many riders, who’d prefer to fit the latest ‘hot can’ than sort the handling.  Maybe point and squirt requires less skill?   [You must be registered and logged in to see this image.]

Bob

Keep us posted Bob....I could be tempted to follow if you bring back some good news on front (& maybe rear) shock upgrades

Nobleswood wrote:

So using the 2006 Suzuki GSXR 750 to get into the system and then added 70 lbs to my rider weight, ( 175 lbs ), to compensate for the weight difference of the bikes ( roughly 420 lbs to 490 lbs ).

These are the baseline shim sets

Compression;

17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.10
15 x 0.10
13 x 0.10
11 x 0.10
 9 x 0.15

Rebound

17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
15 x 0.10
13 x 0.15
11 x 0.15
 9 x 0.30

A 5 weight oil & air gap of 120 mm recommended. However I have changed out the springs, so the air gap may need some fiddling with.

Nobleswood. Did your guy drill a bleed hole in the valves? If so do you know what diameter it was?

cheers
Rob

We didn't need to drill anything.

Your question reminds me of some comment I read in the Racetech book on suspension; after work today I'll see if I can find the reference

RobR,
couldn't find the reference to drilling holes in the valves.
You can email Racetech tech support & see what they say.

I just came back from a 180 mile each way ride to Traxxion Dynamics in Georgia to have my forks re-valved and the rear shock and spring switched out. Dropped it off at 9am and rode away at 1.30pm.  They have a good waiting room and there is a Starbucks and a Zaxby's just up the road so kept myself occupied.

[You must be registered and logged in to see this link.]   Was $699 for the fork valve upgrade and $100 to remove and replace the forks.   I gather that most ship their forks and shock rather than ride in.

I took the Matris M46 KD-ID from my Norge which fits the GRiSO.  They are familiar with the GRiSO and he first said that the OEM shock is good and can be revalved but when he put the Matris on the shock dyno, the Matris went on.  Matris were rubbish at picking the right spring so they put a right sized spring on for $99 and $100 for the remove and replace.

This is my second GRiSO that I have had re-shod (the first in Australia).  As expected is a night and day difference.  Now it holds a line in curves and I don't feel the bumps.

If you are at all considering it, I would do it soon.  Prices are going to go up as everything is getting expensive.

Hope it's not frowned upon to pull up an old thread and reference this techical stuff.

So Pearl, my new to me '09, has a weepy fork seal. Suspension is high on the list to be addressed on these bikes. I'm not well versed with inverted forks, and lack two key things for this, specific tools, and time (It's MAY in USA, for crying out loud)

My plan is to pull the forks and take them to a competent shop and have the seals replaced. I'm thinking that if there is an established imporved formula for a new shim pack, I can request that and consider them good for the foreseeable future.

Searched and found this thread. @nobleswood, where do things stand re: perfomance on the forks?

Anyone else:  Is there more recent common knowledge on the stock forks for upgrade?

Thanks to @usedtobefast for a great thread on the topic.

Nobleswood wrote:

Picking up where Usedtobefast left off.

The OEM rebound stack is;

17 x 0.10
17 x 0.10
17 x 0.10
17 x 0.15
10 x 0.2
10 x 0.2

I have decided to replace the valves with Racetech Gold valves and use the spreadsheets /calculations they provide for the shim stacks. In talking to the Racetech technical department when I found they don't have the GRiSO in their system, he said 'we can roughly calculate a set up and adjust from there'

So using the 2006 Suzuki GSXR 750 to get into the system and then added 70 lbs to my rider weight, ( 175 lbs ), to compensate for the weight difference of the bikes ( roughly 420 lbs to 490 lbs ).

These are the baseline shim sets

Compression;

17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.10
15 x 0.10
13 x 0.10
11 x 0.10
 9 x 0.15

Rebound

17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
17 x 0.15
15 x 0.10
13 x 0.15
11 x 0.15
 9 x 0.30

A 5 weight oil & air gap of 120 mm recommended. However I have changed out the springs, so the air gap may need some fiddling with.

FYI
Out of 3 sets of fork seals that i tried; SKF had measurably less stiction

I’m still happy with the time & money spent for the results I got.
The only change I made was to the high speed compression shims to better handle some ruts on the Interstate that I have to deal with every time I ride.
This evening I’ll look those up & post the change.

I’m interested to hear who you use & how it goes. You don’t have to change the valves, Used to be fast didn’t, but I thought I might as well. The valves were about $300 & not much for the shims

So I the changed the compression stack to;

4# 17 x 0.15
1# 17 x 0.10
1# 15 x 0.10
1# 13 x 0.15
1# 11 x 0.15
1# 10 x 0.15
1# 9 x 0.30

so, took them to a 'metric only' shop where there's retired racer in his late 60's known as something of a tuner. His first question was 'did ya do a sag test'? ANswer of course was no. STRONGLY suggested setting them up stock, but for the 5 wt oil, running the bike and doing the test before messing with it. I bought hisd arguement, that I've got no experience with the bike as yet. So that's where we're at. Forks are back in (@ 4 rings) and I'll run her for a season and see.

He probably knows his stuff.