Forum

[Barry N]

I am changing the fork oil in my 2003 Bullet, mainly for maintenance, since it has never been done before from new (now at 8300 miles). A softer fork action would be a bonus, so I intend putting ATF back in. What came out was 145ml from one leg and 150ml from the other, nice and clean and of a fairly heavy viscosity. Pumping the forks did not produce any more oil. My queries are: A – is there likely to be any more oil in the legs that I haven’t got out? And B – will the same volume (150ml) that came out be sufficient, bearing in mind the recommendation of 200ml? What I don’t want is to overfill the forks and possibly invite seal leakage (and the fork action was very good, albeit on the firm side, with the volumes that came out).

[PeteF]

The oil is there as a damping medium (it gets forced through a hole which damps the action)
As long as there is enough to do this at full travel then everything is fine. However, if the book says 200ml I would put that in. It won't cause any problems.
As to the oil viscosity, after trying several grades I ended up with ATF and it's good for me. I understand it's about SAE 7

[Tim NZ]

Did you 'Tap up' the ends of the damper tubes? There will still be oil in the forks trapped between the lower end of the damper tube and the slider...


13 years between oil change? I'd flush the forks with parafin (or diesel) a couple of times, and allow to drain with the damper rods free off their seat, it takes a while to drain out the last vestige of the old oil/parafin.

[Barry N]

Thanks Tim, I'll try that. Will the damper rods have much resistance, or is it just a matter of a gentle poke with a screwdriver to lift them a little?

[PeteF]

More like a knock with a soft hammer. Don't push them all the way through or they can be a bit of a sod to locate again.

[Barry N]

Ah, think I got it now – the male thread that is exposed when the drain nut is removed, IS the damper rod, yes? So if I slip the nut back on a few turns to protect the thread (and to stop the damper rod going up too far!) and give it a tap – that should do it then?

[Tim NZ]

The fork springs will keep pressure on the damper rod. Simply refit the cap nuts 4-5 turns, tap up on the nut with your favorite BSW/BSc imperial hammer, (DO NOT ever use a Metric hammer!) just enough to unseat the rod...

[PeteF]

When you come to tighten up the nuts you might find the stud spins. Either take it by surprise by tapping the spanner and/or get some tension on by compressing the suspension. A ratchet strap is useful for this.

[Barry N]

Thanks for your help Pete and Tim. Job done!

[jefrs]

I know this is different to the 2003 - The 2009/10 Workshop Manual for the EFI specifies 265cc of SAE 10W-30 each leg. I.E. the oil is a 30 viscosity oil, it's not all that thin. However, having spoken to the dealership, it would appear that there are several suitable fork oils available to adjust the damping of the forks, and doing the job (which on this model entails removing the legs) is £90.