Jump to content

K-Tech suspension (Long)


skipperT

Recommended Posts

  • Premium Member

Air gap, viscosity, correctly setting where the rebound rod starts to act, spring rate, C & R settings, spacer length (can't you fish it out with a hook on the end of a coat hanger?), all effect the ride.  You sure you got everything right?  I'd put the spacers on top of the springs for ease length adjustment...which can be adjusted in fine increments with washers available from RaceTech.

I have Matt's cartridges valved to my liking with rebound & compression in each leg and a right cap also on the left. New upper and lower bushings, seals and wipers.  Spent hours polishing the tubes.  Added some Race Tech washers on (that alsoprotect) the OEM plastic spacers (from the) .95 Sonic springs, 16 cSt syn fluid (would have to look up air gap but maybe around 155 mm), and at full stoppie and major high speed bump I have about 20 mm from bottoming, perfect.  A Razor R and 230 mm rotors with HH+ pads all bring it together very nicely!

Hope my pics help too.

20190102_174133.jpg

20190102_174225.jpg

20190102_174511.jpg

20181228_182727.jpg

20181223_092022.jpg

20181223_153822.jpg

20181223_092038.jpg

20181218_192828.jpg

20181218_203409.jpg

20181219_201824.jpg

20181220_183153.jpg

  • Like 1
Link to comment
Share on other sites

In a moment of temporary insanity a while ago, I had all the tools required for a fork cartridge install, sat in my internet shopping cart and I was one click away from ordering them. I was buoyed up by wearing beer googles, it was late at night and my inner workshop hero was whispering in my ear, “it looks difficult, but you can do this!”

Thankfully I closed my ipad without ordering, came to my senses and dropped the forks off to a local specialist. I have huge admiration for you guys who attempt this, as it is beyond my skillset, along with valve gap adjustment when that comes around. I enjoy spannering with a clear set of instructions but forks innards look like mechanical voodoo.

Good luck @skipperT, I hope you get this sorted.👍🏻 

 

  • Thumbsup 2
  • Thanks 1
  • Haha 2

Red 2015 Tracer, UK spec (well, it was until I started messing with it...)

Link to comment
Share on other sites

13 hours ago, skipperT said:

Yes, weight off the bike.

I'm measuring 26-28mm of Total sag in the Front.

Bike standing (upright no rider, and suspension "settled") Front sag=15-18mm. Rider added increases the number to 26-28mm (so stiction is between 2-3mm depending on measurement accuracy)

These measurements are with the preload measurement backed-off all the way CCW.

Did you happen to receive a parts list (with part numbers) when you received your suspension? Just found some documentation from my experience with the IDS system..

Spacer: 120-221-128

Spring: 36-260-VAR (I'm assuming VAR is going to indicate the rate)

'15 FJ-09 w/ lots of extras...

Fayetteville, GA, USA

Link to comment
Share on other sites

1 hour ago, duhs10 said:

Did you happen to receive a parts list (with part numbers) when you received your suspension? Just found some documentation from my experience with the IDS system..

Spacer: 120-221-128

Spring: 36-260-VAR (I'm assuming VAR is going to indicate the rate)

Honestly not sure. I have the install instructions but don’t recall if there’s a parts breakdown in the booklet. 

-S

Link to comment
Share on other sites

FWIW I have been playing this suspension game for a few years and here's my method of determining spring selection for any street-going motorcycle, front and rear.

Sag determines spring selection and the spring has to be right before damping can be set effectively. (leaving stiction out of this discussion) 

1.  Static (unloaded) sag should be 10-15% of total suspension travel. (Note: this is % not mm)

2.  Rider (loaded as usually ridden) should be 25- 35% of total suspension travel.

The difference between these two numbers (15-20%) reveals that the spring is correct. 

The lower end of these numbers will provide a stiffer ride and the higher end will provide a plusher ride.

Preload is only a ride height adjustment and doesn't affect much else.  If your difference between static sag and rider sag is close to 15% of total travel but the actual numbers are high or low, that is when preload is used to shift both of the numbers into the desired range.  (spacers found in spring kits are for gross preload adjustment and are usually cut close to the correct length by the factory, but you can cut them if required)

I have also found that setting damping is easiest like this:

1.  With compression damping set very low (even as low as it will go).  Set rebound somewhere less than you think it should be and ride/adjust until gentle road irregularities result in only one suspension cycle.  Be careful at this stage as it will ride like a pogo stick if rebound damping is too low.    (you will also have to ignore brake dive in this phase of tuning the front end) 

2.  When you find the best rebound setting start to add compression damping until you get the firmness of ride that you like. 

3.  Fine tune to your taste from this point. Placing a zip tie on the shock rod and fork tube will allow you to discover how much of the suspension you are acutally using.  This can tell you of you are bottoming on sharp road irregularities or if you have the damping set far to firmly.

 

As always  YMMV

Edited by BrianG
  • Like 1
  • Thanks 3
Link to comment
Share on other sites

Thanks for chiming in BrianG.

Found this late last night, Dave Moss feels that GREATER than 15mm of preload in a cartridge fork is too much: https://youtu.be/ICK_2tX9_Qg

I also found this http://www.ustream.tv/recorded/5350380good 

 

So some good info there.

I'm going to measure some things up, cut the preload spacer a minimal amount, re-assemble the bike and measure sag again to see if I'm in the ballpark. 

-Skip

 

Link to comment
Share on other sites

  • Premium Member
3 hours ago, duhs10 said:

Just for your reference @skipperT

 

20170708_130252.jpg

 

 

Skip-  Thanks for the compliment on my shop.  It's only 22' x 10' but has about 18 feet of work bench (there's a 77 RD400 waiting for its engine under the blue foam cover under the 2-height tall bench behind my ancient B&D Workmate), tons of shelves, lighting so that sunglasses are De rigueur, heat, AC, carpeting, a fridge, tunes, WiFi, a tool chest and many special tools, stands and jigs I've welded up, my VTR is on my 25 year old Handy Lift behind the FJ (I have a small lift and 2 sets of F&R Pit bull stands), there's a 5.5 foot wide pocket door from the garage on an electric operator so I can ride in from the garage (which is detached 45 feet from the house but the wife still complains it's too close) up a ramp because the shop floor is level and the garage floor pitched down back-to-front to the 18 x 7-6 OH door, and there is a man door directly into the shop (the Bret Cave).  I have a little machine shop in my basement.  My "make shift" fork spring compressor set-up works quite well.

While not knowing the volume absorption of the K-Tech cartridges, IMO 140 mm of air gap is too little.   I'd increase it 5 mm and it may take another 5. 

  • Thumbsup 1
Link to comment
Share on other sites

2 hours ago, 2and3cylinders said:

What?!  Your in near-term communication with Matt?!!

Haven't talked to him in a while but I call to check on him every once in a while...

'15 FJ-09 w/ lots of extras...

Fayetteville, GA, USA

Link to comment
Share on other sites

  • Supporting Member
Just now, duhs10 said:

Haven't talked to him in a while but I call to check on him every once in a while...

If you talk to him, tell him his services are in demand, if he focused his attention to only building forks he could do very well.

  • Thumbsup 1

***2015 Candy Red FJ-09***

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×