2001 Katana 750 (GSX750F) rear shock DOES work!

[lamoun]

Just to let you know, 2001 Katana 750 (GSX750F) rear shock DOES work!

It just needs to widen the mounting holes on the shock a bit.
It is a bit taller than the stock, much stiffer and fully adjustable! No problem with side stand or center stand.

Will came back with some pics and sag measurements, compared to the stock.



UPDATE

Be sure to check the chain slack, fitting a new (longer) shock. Danny500 found that he needed 1.8inch slack or else the chain will bind, with gory results.. http://gstwins.com/gsboard/index.php?topic=48259.msg542501#msg542501

Thanks go to Danny500 and ineedanap.

[psyber_0ptix]

are you able to adjust the preload and sag by rotating the pirch with a spanner wrench? much like a coilover on cars

[The Buddha]

What you mean widen the mounting holes ? Like drill it a bit ?
I didn't think so ... which is why I send it to Psyber_optix just earlier today ... I didn't touch the holes psyber.
The 2 lock rings are to be rotated and locked against each other for preload, the rebound is on the bottom at the clevise and the compression is on the reservoir.
Cool.
Buddha.

[lamoun]

What you mean widen the mounting holes ? Like drill it a bit ?
I didn't think so ... which is why I send it to Psyber_optix just earlier today ... I didn't touch the holes psyber.

Yeap! I had to drill them a bit. Not because they where too small or anything, but I couldn't line up the shock holes with the ones on the cushion lever. That was because, the shock is much wider than the stock and the spring was touching the swingarm.

[The Buddha]

If that happens, grind that section of the swingarm.
Its a old and beaten discussion. Shocks take a lot of load ... I'd totally refrain from touching anythign on it. That section of the swingarm is build for bear ... huge thick plate bent into a 90 degree ... go at it with an angle grinder ...
Cool.
Buddha.

[psyber_0ptix]

is that picture below (b/w photo) of a gs500 cushion lever? mine's stamped steel so it seems

cant wait to finagle this in soon. i have my grinder at the ready

[The Buddha]

That is 89 only ... cast aluminum ... that steel one I like it, we can grind it up to fit ...
Cool.
Buddha.

[lamoun]

If that happens, grind that section of the swingarm.
Its a old and beaten discussion.

Damn... I had read that but i forgot.. 

Anyway...

SAG Measurements.

Rider with gear ~95kg

Stock shock (full preload)
Free sag:   14mm
Rider sag:  49mm

Katana shock (Lower limit suggested by service manual)
Free sag:   6mm
Rider sag:  36mm

[The Buddha]

When I did mm75658's bike, It didn't hit. Lately though he's been hearing a scraping noise he said from there.
I am thinking I just grind it a little ... I took my angle grinder to his place to grind up stuff, but we had no time when we did his Kat FE that night.
Cool.
Buddha.

[psyber_0ptix]

after install, how does one go about tuning. is it based on comfort/experience

mix matching shocks throws factory recomendations out since dampening and springrates are different no?

[The Buddha]

Trial and error. Post here and I'll point you ... I am not as good with it as with carbs ... but I'm learning.
Cool.
Buddha.

[lamoun]

First you must set your preload.

Put your bike on the center stand and measure the distance from the wheel axle to, lets say, the lock of the seat. This is L1
Then have a friend to hold the bike upright, (not putting weight) and measure again. This is L2
Gear up sit on the bike (feet barely touching down, or even better have another one hold the bike from the handelbar), and have a friend measure the distance again. This is L3

Now L1 - L2 = free sag
       L1 - L3 = rider sag

You should adjust the preload so the Rider sag is about 30 - 35mm.

With the rider sag adjusted, Free sag gives an indication whether the spring is hard or soft for your weight.

5 - 10mm and the spring is fine
free sag > 10mm --> Too stiff spring


The check for rebound damping.

A rule of thump, is to press down the rear of the bike and let it come back freely. It mast come back but not overshoot the original position.
If it overshoots increase rebound damping.

There is no rule about the compression damping.

Also, pushing your bike back and front simultaneously you want both ends to come up evenly, at the same speed.

A question, is there a stop to the rebound damping dial, or you can go from 4 to 1 (like 1-2-3-4-1-2-3)??

[The Buddha]

Dial for rebound will keep spinning ... No stop.
Cool.
Buddha.

[lamoun]

Dial for rebound will keep spinning ... No stop.
Cool.
Buddha.

Thank you Budda! And I thought mine was broken or something.   

I'll put this here for reference.

[psyber_0ptix]

how did you mount the resevoir?

[The Buddha]

Wiggle, fiddle and zip tie and hose clamps. But he can post for you.
Cool.
Buddha.

[psyber_0ptix]

mounted mine up the other day. it was so straight forward it was ridiculous.

i didnt have to grind anything, there was JUST enough clearance with the swing arm, and even more once compressed.

i have dampening and rebound set to softest settings. DAMN its stiff. barely any free sag. even less rider sag.

i'm having a difficult time positioning the reservoir aesthetically but i have it mounted up and its accessible.

but i'll probably post up my own thread soon after i get the exhaust welded on this weekend. i know buddha is going to have some words about it as it seems not many folks on the forum likes the chopped rear/no fairings on a bike hahah.

[The Buddha]

Oh ... kat shocks are toss in and ride.
Even the remote reservoir ones ... The shock is actually just a shade longer than GS shock ...
You prolly need to ride about on it, the shock can be stuck from sitting. I sorta like opening them up as many people have asked me to as part of a powdercoat thing.
Non fairing look ... meeeeh ... Dont think it looks great, but hey, it is what it is ...
Cool.
Buddha.

[psyber_0ptix]

oh darn! i wish i had known so you could powder coat the spring to that amazing blue to match the tank/fork brace


lol.

i dont have money for repaint and replace the old cracked fairings that came with the bike. :X thats my excuse anyway

[The Buddha]

Yea ... OK fine ...
I am able to do a lot of things ... patience and money is the limit.
That blue though ... figure 30 bucks minumum for spring and collar and 1/2 moons. Maybe even more. Then the body will be gold and it will clash ... that should be silver ...
That color is speckled silver, under candy blue ... look at it in the daylight and it shines and glitters like a speed boat ...
I am resering that color for body parts with high light exposure, its $$$ and putting it on a shock that lies under the bike is a waste.
Regular color powder ...  Right now I am working on ...
1 yellow and black ... = tiger, one white and black = white tiger and bombadillo's - blue and black = blue tiger ... 
Cool.
Buddha.