What grade of Fork Oil

[Jim_C]

Hi all, I've a '99 GSX750F and I think the front forks are due a service. Took the top nut of today and extracted the damper rod and the oil is quite grey. So I'm planning to change the oil next week end. I've a couple of questions:

1. Can you recommend a suitable grade of oil, I think I'd like to use a slightly thicker oil, any thoughts would be appreciated. How much oil does each fork take?
2. The dust seals look like they're nackered, is it Ok to change these on their own or should the oil seals be changed also, the oil seals look fine in that there is no trace of an oil leak and the oil level seems OK.
3. Is there any link on here to a "how to section on the fork oil"

Thanks for your comments.

Regards

Jim

[squiggy]

Ooooo...I get to toot my own horn.

http://katriders.com/vb/showthread.php?t=90203

That, and there's a whole seperate section on suspension here.

Took the top nut of today and extracted the damper rod

I'm curious how you extracted the damper rod by only removing the top fork cap. The damper rod is bolted to the fork bottom. You have to dissasemble the two halves of the fork to get to it.

Unless you meant the springs.

[Jim_C]

I think I'm getting mixed up, I removed the long thin tube attached to the top nut, I think this actually only adjust the damping. What is this called?

[md86]

Nope , that's the damper rod .
10w is stock , 15 weight if you fell the need for a stiffer ride . Or just get 10w and put in a spring shim of some sort . I stacked washers on mine , and made a longer spacer out of PVC . Both methods work fine , but the washers are kinda "tunable" .

[Jim_C]

Thanks for that, the linked section states 513ml of oil per fork, is this the same for the GSX750F?

[arsenic]

no, that's NOT the damper rod the damper rod is the thing that the bottom bolt bolts into, that's just a rod

http://fiche.ronayers.com/Index.cfm/Module/Main/TypeID/26/Type/Motorcycle/MakeID/2/Make/Suzuki/YearID/36/Year/1995/ModelID/6407/Model/GSX600F_KATANA/GroupID/265755/Group/FRONT_DAMPER_MODEL_K_L_M_N_P_R_S_T

#15 is what is referred to as the "damper rod"

[Jim_C]

check my manual it calls it the damping ADJUSTER rod, makes sense as this is what the click adjuster on the top nut travels through to the actual damping rod.

Started the job tonight and have had to give up. The forks are out and drained, dust seals now off and reveal that I really should change the oil seals as they look to be in a bad shape altough no real signs of leaking. However I cannot get those bitches to budge one little bit. I've pumped them til I'm blue in the face and still no sign of them moving. Yes I've removed the steel retaining clips on top of the seals.

Even tried soaking the top of the seals with WD40 (penetrating fluid) and left them for half an hour and tried to pull the tube out again, still no budging. It's just after 9pm here and I'm giving up for tonite. Can anyone offer any tips or tricks as to how I could get the fork oil seals out.

Any comments really appreciated!

Thanks and regards


Jim

[arsenic]

did you take the bottom bolt out? Look in the lower fork tube, where the axle goes, up in there there is a bolt, you need a 6mm allen wrench, if you don't take that out, good luck getting those apart Let me rephrase, I don't really need to ask you, I KNOW you didn't take that bolt out, DO IT!

[Black_peter]

did you take the bottom bolt out?

Yeah, it would be bad actually if you did get the seals out without removing that bolt!

Here is a good description:

http://www.motorcyclistonline.com/howto/replace_fork_seals/index.html

[Jim_C]

Nope didn't take it out, am I too late to take it out now?

[arsenic]

no

[Jim_C]

Thanks, they're out now and the forks are separated. Seals def. look past their best. Now I'll polish up the lower forks and wait for the seals to arrive on Thursday. No doubt I'll be back when I attempt to rebuild them towards the weekend.... Thanks again!

[arsenic]

[legacycycles]

I used 20wt oil in my pre and honestly cant tell a difference.But i like a stiffer suspension anyway.

[arsenic]

I hope so, cause that would be REALLY stiff.