What fork oil?

[Fiddlesticks]

The Tiger Explorer 1200 manual says 5w fork oil, but my usual style of riding is to push on a bit, often with a pillion. I'm thinking of going to Motul 7.5w.

 

(No idea what's in there at the moment.)

 

Seem like a reasonable idea?

[husoi]

If you ride more on the rough side then yes you can even double to 10w.

As option and if you want to be meticulous about it.

Get 1 bottle 5w and 1 bottle 10w

Mixing it 50/50 will give you the 7.5w

Changing the ratio will vary the w value

[Fiddlesticks]

Genius idea @husoi

Nice to have options.

I'll start at 7.5 and work up next time if needed.

[Mississippi Bullfrog]

The thing is that the same number from different brands gives very different handling. So don't just go by the numbers.  One brand of 10w will be different from another 10w.

 

You really need to experiment until you find what works for you. I put Putoline 10w in and didn't like it. I drained that out and replaced it with Smith & Allen 10w and much prefer how it handles. 

 

You can also play with the air gap. 

Edited March 24 by Mississippi Bullfrog

[Stu]

You need to Google centistokes when it comes to fork oil and the weight 

 

The same weight oils can behave differently depending on the centistokes value which is the viscosity of the oil 

 

A higher weight oil can have less viscosity and be worse than what you have 

[RideWithStyles]

Correct.

also its quicker to work out things to start with:

what settings (pre, comp, rebound) are in the forks now? 

what oil was in the forks before?
How old or degraded was it and how was its behaviour when new and it at now?

What level/volumes was it set at?

And how you what to change its behaviour for new and over its service life time….

http://www.peterverdone.com/suspension-fluids/.

lets assume was it Motul comfort oil 5wt in your forks: 18.2 cst 40*, 4.0 at 100* 124 vi.

and you wanted to stiffen it up just a bit:

factory line med5-10 is 22, 6.2 and 254, so what that means is it’s just under 1/4 thicker at low heat but 1/3 thicker when warmer yet the properties/stableness will two and a half times longer. 
if you put in their comfort medium 5-10 is 35,6,115, so it would be nearly double the thickness at low heat but almost the same as the factory at higher heat but last less than the comfort oil.

if you put it silk 5wt, 22,4.4,106. It would be marginally thicker but last even less.

put in pro rst5wt, 26,9.4,372. Noticeable thicker when cold, very stiff when hot yet last WAY longer than the others to the point of 3 times…

castrol syn 5wt, 28, 5.7,151, just under half the thickness again when cold, just over 1/4 when hot yet only last slightly longer.

silk 10 34.8, 7, 169. 3/4 thicker yet only last slightly a bit longer.

castrol 10 is 42,7.5,150 not quite twice as thick only lasts abit longer. 

castrol 15 is 46,8.3.150. Slightly more than Twice as thick but the grade of quote should be three time as it a 15 you would have thought yet only fractional more than the 10.

silk pro 10 rst is 47,13,303. More than twice as thick cold, more than three times thicker when hot yet last slightly more thantwice as long…

 

thats before you think of the other brands, how your forks design will work with the oil, setting of the fork, time of year, how hard you work the bike…

so are you just gauging from what the bike is doing now, with the settings in now?

so when new 2 out was good, if your oil is goosed your at 1/8 out and it’s pogoing still. seemed ok when new.
you could just put in the same oil or very close to it but the new one will be good again but just say its normal will be 1 1/2 out, just change a touch sooner.

 

 

 

Edited Friday at 11:52 by RideWithStyles

[Fiddlesticks]

All good points. Appreciated

 

It's a question of getting a baseline at the moment. The oil in the forks has been in for 2 years and 26,000 miles. Last time it was done by the garage, so no clue what brand or weight was used.

 

The plan is to start with Motul 7.5W, using the  @husoi method of 5W mixed with 10W - due mostly to availability. Recording all the settings and volumes should give a good starting point if tweaking is required.

[RideWithStyles]

Well goosed is that oil!!!

Was it dealer or other?
more than likely they would have put in 5again, assuming again but even so which one? Do they have a brand loyalty?

 

colour of oil will give a clue most of the time, red is 10wt for example.

 

if you ride all rear round I would consider the cold rating, and if your doing that many miles in a year I’d try one that will at least last longer/stability second.

if you ride summer only id stick to the hot rating with less difference between the cold.

just go with a brand you like, trust, can get hold of easily and use the info in the site now you have d

some idea how it work to narrow down what you want the bike to behave like.

 

Recording is good, mixing can be beneficial but just be wary that as the details show above that they are not consistent in behaviour between own brands wt grades let alone different grades or models nor mathematically consistent. Its a minefield and a dark art…

Edited Friday at 12:07 by RideWithStyles
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[husoi]

If you're only changing the oil then it should be a quick simple operation.

Play attention that if the oil is kinda grey then it's very likely the teflon in the bushings is gone and you should replace them.

Yes means you have to take the forks out and strip them but replacing the oil with worn bushes is a bad idea.

[Fiddlesticks]

@RideWithStylesNah, not a dealer - local shop. Not sure at they used.

 

1 hour ago, RideWithStyles said:

Well goosed is that oil!!!

 

Believe it or not, it's well within the posted service schedule:

 

That's 40,000 miles!

 

The workshop manual I'm using disagrees with that strongly.

 

22 minutes ago, husoi said:

Yes means you have to take the forks out and strip them but replacing the oil with worn bushes is a bad idea.

 

Yes, that is the plan. New bushings, seals etc. Might as well give it the works.

[husoi]

Experience will tell you.

Do it properly and you're doing it once

[RideWithStyles]

1 hour ago, Fiddlesticks said:

@RideWithStylesNah, not a dealer - local shop. Not sure at they used.

 

 

Believe it or not, it's well within the posted service schedule:

 

That's 40,000 miles!

 

The workshop manual I'm using disagrees with that strongly.

 

 

Yes, that is the plan. New bushings, seals etc. Might as well give it the works.

Some triumph manuals say not and never change the preload on the bike .
 

Some service manuals state not to change the fork oil ??

 

I know it’s 5wt so its almost like water but I wouldn’t trust the book for that quote and go anywhere near that miles till a change.
I mean you change engine, brake, coolant etc quite often, why not the fork? It works very hard virtually all the time for the tyre, bike and you…

[Fiddlesticks]

Well, I've gone and stuffed that up!

 

Following quite a detailed workflow, but obviously missed something. New SKF seal kit - tapped in with a seal driver. (The right way up.)

 

As soon as under load they're dripping. I've taken them all apart again and ordered replacements, just to be on the safe side.

[husoi]

Surprised SKF malfunctioned.

I never used a seal driver for the forks.

Old seal and a bit of 38mm (cut in length) or 42mm  drain pipe does the trick perfectly.

The old seal is then removed easily and job done.

[Fiddlesticks]

It's def. looking like the seals. Put new Slinky Glides on and straightaway they feel snug and tight. Fresh oil (fully synthetic this time) which means they've had a good flush after being left draining last night.

You never know until you ride, but they're all back together and bouncing around on them reveals not a hint of misting - just the tiniest bit of rubber grease residue. 10x better than last time.

Still cheaper than going to the garage, but I wanted to learn how to do it anyway, so a bit of a failure was not a big deal. Although... Two days commuting by car an I'm climbing the walls!

Will reassemble and test ride tomorrow.