650 fork oil

[Hondaman]

I thought I'd put some lighter oil in the forks with a view to trying to make them a bit less harsh/more plush over bumps & potholes etc I did this by syphoning some of the old oil & replacing with a mix of 2.5 & 5wt oil that I have in stock,  maybe reduce the air gap slightly while at it.

Now, my Haynes manual says 139mm air gap for the Glee (spring removed, forks fully compressed), after carefully removing the springs, the air gap measured 178mm!

I removed ~170ml of oil from each leg,  adding about 80ml of 2.5wt, topped the rest up with 5wt - a total of 215ml of oil was required to bring the air gap to the manuals stated 139mm.

Is the Haynes air gap of 139mm correct for a '13 reg Glee?
And before anyone says, no I didn't lose half the oil removing the spring (although you can't help losing a dribble or two) & yes, the forks were fully compressed, if the spec is correct, where has my oil gone!

[UK_Vstrom650]

139mm according to the service manual. Not sure where your oil went...

Going to change my fork oil at some point over Christmas as will be installing new tyres - manual says 530ml in each leg. Any tips welcome.

[tallpaul]

Interested in this as I too am planning to change my fork oil while my tyres are changed. I'm also doing tappets while the front end is off. Easy access!!

[Hondaman]

Thanks for the confirmation of 139mm, at least I'm not going mad!
I'm assuming the forks were underfilled from the factory.

I reckon the mix in there is 6.5-7 wt, a quick run out yesterday showed a definite improvement in ride quality from the front, I had a short run on a local cobbled & potholed track, the bike rode much better than when I tried it in summer when it felt quite horrible.

I wouldn't hesitate to go to 5wt if doing a change although this would be with the emphasis on ride quality maybe at the sacrifice of spirited riding stability.

Phil

Edit, re reading  my original post, it's a bit information overload.

Main points:
Stock oil is 10wt, air gap in my bike was 178mm
Current oil ~7wt, stock air gap of 139mm

Not all fork oil of a given wt are the same viscosity

[UK_Vstrom650]

I may know what happened to your fork oil...

I went to a local motorbike shop near me to buy some fork oil. They only stock Putoline oil in 1 litre bottles (10w) for £10. As each leg takes 530ml, he said only use one bottle between them as "you won't drain all the oil out anyway, and that's all we'd do if we were doing it in the workshop..."

Maybe yours had been 'serviced' at some point?

[Hondaman]

Good point but it was a virtually brand new bike when I bought it with only 600 miles.
It's still under 3k now so not lost through general use etc, obviously no leaks etc

[UK_Vstrom650]

Maybe the factory follows the same philosophy  I'll let you know what mine measure when I change my oil 

[Hondaman]

A runout into rural Cheshire yesterday via some potholed crap strewn back roads
There is a definate improvement in ride quality with the lighter fork oil, a bit more fork dive on the brakes but nothing to worry about.
If I get a mo, I'll take a bit more out & replace with lighter 5wt & see how that is