SV1000N K3 fork question

[Mark_h]

One for the guru's. No disrespect to the helpful folk who will re-post lots of advice but ideally I need some info from someone whose done it for real.

I've got a K3 SV1000 with a standard front-end. I've been doing a lot of googling and have read the manual and all the usual stuff and I now have so much contradictory information that I'm probably now worse off than before.

Current plan:-

Take forks off (having first loosened the top caps and made note of existing pre-load, compression and rebound settings.)

Caps off, remove the cup shaped C washer. Loosen the adjuster rod lock nut, then unscrew the fork cap/preload assembly. Remove the plastic spacer and the fork spring, noting which way up the spring was.

Tip out crud, pump stuff and leave upside down for a bit.

Refill with new oil (Question 1)
Pump until no air
Check oil level (Question 2)

Put back together, put back on bike, marvel in the transformation of my slightly wayward handling.

Question 1:- Oil weight
I'm about 14 stone (200 lbs)
Standard springs
It seems according to my research that something between 2.5 and 15wt mostly 5w and 10w come out as the most popular although each manufacturer's weighting varies so one manufacturers 2.5 may be thicker than someone else's 10 apparently. What would be a recommended oil weight and manufacturer?

Question 2:- Air gap
Apparently the N has a smaller gap than the S and the K3 may well be different again. The volumes also vary but I assume that given my initial intent to go with pumping and tipping rather than a full strip I can't guarantee it's going to start completely 100% empty so best going for gap rather than volume. I assume this is measured with spring out and shock compressed.

Main PDF suggests 162mm gap, with 494ml oil
K3 1000N supplement does not cover gap but says 508ml oil
Google seems to go for 135mm airgap for a K3-N

Now I doubt the 12ml difference will account for almost 30mm of height difference so not quite sure what to do here. I can measure what's there before I drain but most seem to be random and different between legs.


So in summary
Q1. Which weight of which manufacturer oil
Q2. What air gap
Q3. Have I missed anything crucial?

Ta muchly

[Sid Squid]

Oil weight: Depending on who you talk to,(and I know enough people who ought to know to now know there's no real concensus), the recommended oil - L01 - is either 2.5, 5 or 10W oil, lacking any certainty I went for 5W, which works perfectly well, I used Rock Oil as the lack of certainty in original weight meant any other variable didn't really matter either.
I can state with certainty that my SV1000, (naked), front suspension works as well as it did as standard with this oil, bearing in mind mine is not on factory settings, and any fall off in performance was restored by the oil change enough that I haven't wished to reset afterwards.
There are certainly differences in exact weights of differing manufacturers oils, I sincerely doubt that one makers 2.5 will match another's 10, and 15W would be way over the top for any modern cartridge fork. My use of 5W, (whatever the brand), tells me that even 10 would be rather stiff, whatever the settings.

Air gap; I have the original Suzuki manual that has such info, but not right here now, I shall get it and post up the setting, assuming no-one else beats me to it of course.

Bits you may have missed: Not that I can see.

I originally rebuilt my K3S forks with 10W Silkolene but they were way too stiff. 5W was much better. Nobody seems to know what spec the magical Suzuki L01 oil is.

7.5 weight oil I think you will find pretty good ie Putoline or similar plus go with factory settings

[yorkie_chris]

7.5 putoline is pretty thick.

I use RSF5 or putoline synthetic 5 for forks like that.

[Mark_h]

Sounds like 5w. Still have looking for feedback on the airgap though. Origing question reposted below to save scrolling:-

Question 2:- Air gap
Apparently the N has a smaller gap than the S and the K3 may well be different again. The volumes also vary but I assume that given my initial intent to go with pumping and tipping rather than a full strip I can't guarantee it's going to start completely 100% empty so best going for gap rather than volume. I assume this is measured with spring out and shock compressed.

Main PDF suggests 162mm gap, with 494ml oil
K3 1000N supplement does not cover gap but says 508ml oil
Google seems to go for 135mm airgap for a K3-N

Now I doubt the 12ml difference will account for almost 30mm of height difference so not quite sure what to do here. I can measure what's there before I drain but most seem to be random and different between legs.

[Bibio]

if you've not already stripped the forks then measure the air gap with the old oil in. if you have then don't worry to much about it and stick to what the PDF says. as far as i know the air gap only comes into play at the bottom of the stroke anyway. remember to purge the cartridge of any air before you take the air gap measurement.

[punyXpress]

Spring weight.
At your weight, are the the springs going to be right?
On the basis that 650s are way too light, does the same apply to the full size ones?
If you've got to replace them, perhaps now is the time to do it.

[yorkie_chris]

162 is big, are they progressive springs as stock or something?

I usually start at 125mm and play with it from there, pretty much regardless of bike.

Originally Posted by Bibio

if you've not already stripped the forks then measure the air gap with the old oil in. if you have then don't worry to much about it and stick to what the PDF says. as far as i know the air gap only comes into play at the bottom of the stroke anyway. remember to purge the cartridge of any air before you take the air gap measurement.

You won't get it right as you'll pull some oil out with the springs.

[Bibio]

yup but it will be around the figures he is looking for so can take an educated guess