Fork oil weight...10w or 15w..what do You use?

[Ronin]

Howdy..I'm in the middle of the joy's of fork seal repalcement.I know for stock springs the oil is 10w.I'm wanting to slightly stiffin up the puppy's.
I've read some people use 15w..while others say you could cause a high speed wobble using 15w,rather than stock 10w.I don't want to go with progressive springs just yet.
What's your suggestions??

[galahs]

10W with 0.85kg/mm sonic springs 

[ajaxgs]

myself i went with the 15w and progressives , much beter than stock and bought the fork brace from chuck , but waiting to get rid of the snow to try that out

[coll0412]

23W for the race bike

[ben2go]

Progressive springs and 15w Rotella.I then had to up my rear shock to a Katana.My project bike has a stock 650/750 Katana front end.I beat the stock GS springs all to hell in the first 500 miles.I weigh 200#'s and the Progressive set up is the stuff for my mountain rides.

[galahs]

and bought the fork brace from chuck , but waiting to get rid of the snow to try that out

Mate if you ride on undulating roads it makes a noticeable difference. 

[Teek]

I have Sonics (.85) with 15w, and a Katana 600 rear shock. The bike is stiff as heck, but it handles really nice in the canyons. I weigh about 150 geared up. I have the Katana set soft too. In retrospect I would have chosen the .80 springs, but the front end is solid and responsive, and it's not really rough or anything. I think I'm going to tweak the preload, I probably have a hair too much. So I don't know about wobble, I have no vibration or wobble. 
If I was you and going to the bother of changing the fork oil, I'd put new front springs in, you would not regret it! No more bottoming out over little bumps.

[Y2K6GS500F]

I'm using 10W with .90 Sonics.  I'm about 200lbs with gear.

[beRto]

Progressive and 10W

[kml.krk]

Progressive and 10W

+1

I'm only 150lbs so it's stiff enough.

[Kerry]

Same here.   Uhhhh, I mean the Progressives and the 10W oil, not the 150 lbs. 

[RichDesmond]

Howdy..I'm in the middle of the joy's of fork seal repalcement.I know for stock springs the oil is 10w.I'm wanting to slightly stiffin up the puppy's.
I've read some people use 15w..while others say you could cause a high speed wobble using 15w,rather than stock 10w.I don't want to go with progressive springs just yet.
What's your suggestions??

If you're leaving the stock springs in there use 10w, or at most a 50/50 mix of 10w and 15w. Straight 15 is a little much for the stock springs.

[Ronin]

Thank's everyone for the response's......Gave me a fair amount to ponder

[Bob Broussard]

Who came up with front end wobble with thicker oil

The heavier oil improved the front suspension enough to expose the weakness of the stock rear shock.
Front end wobble actually is caused by the rear suspension creating an oscillation because it's too mushy.
Or it squats under accelleration allowing the frontend to get light and cause headshake (on high HP bikes) 
There are exceptions to this of course, but I've found it comes from the rear alot more than you'd think.
Shifting your weight further back on the seat will help settle things down if this happens.
I use 20wt oil with Race Tech .85 springs. (165lbs with full gear on)
Fox shock on rear
This is pretty firm for normal street riding, but perfect for aggressive riding or track time.
So consider what style of riding you do most.
Stock forks with 15wt should be fine for comfortable street riding.
If you start pushing hard enough you'll find it too soft.
It's always a compromise

[ecpreston]

a little late to the party, but for me (~200lbs), the cheapo method of keeping the stock springs and using 15w oil has helped a a bit. Obviously not ideal, upgrading the springs would be the correct thing to do, but it helped on both the street and track with no ill effects.

[Ronin]

Thank's again to all....can't afford the springs this year with all the mods and updates I've done this winter.So I'm going with 15w and the stock springs.
I'm making a stainless fork brace top plate,also.So that'll help to.

[spc]

OK, so who's gonna try 80w gear oil???  I just wanna see what happens...............

[Ronin]

What's the weather like down there??

[galahs]

OK, so who's gonna try 80w gear oil???  I just wanna see what happens...............

Would probably prevent fork seal leaks 

[Susuki_Jah]

15w, with 1.5" extended dampening tubes . very stiff but very awesome