11 replies to this topic

[Hammerdown]

I've got an HS4 on a 1989 1000 with a stage 1 kit fitted.

How long should it go between dashpot top-ups?

It seems to need doing every week. Does this mean something is worn out and needs replacing?

Cheers

[H.M.M.]

If you top up too much oil you will find that when you open the throttle fully access oil will come out of the top of the plunger. This is because the piston lifts and pushes the oil out. If your like me and drive everywhere on half throttle when I do open her up I get oil all over the dashpot. But I check mine monthly.

[Hammerdown]

Don't think that's happening, but I'll have a look next time I take it for a run.

I'm topping up to the point about 1cm down from the top, where the internal diameter changes.

Cheers

[jimnali]

The oil provides damping so only needs to cover the bottom of the piston. If you can still feel some resistance then there is sufficient oil.

[H.M.M.]

Don't think that's happening, but I'll have a look next time I take it for a run.

I'm topping up to the point about 1cm down from the top, where the internal diameter changes.

Cheers

Sounds like your filling it up too much and access oil is coming out of the plunger.

[ACDodd]

The problem here is the way you are checking, Do not remove the piston rod. Simply unscrew and move to the side. Look in. If you remove the rod, you remove oil at the same time do this 3-4 times and its empty.

AC

[MiniLuke]

Don't think that's happening, but I'll have a look next time I take it for a run.

I'm topping up to the point about 1cm down from the top, where the internal diameter changes.

Cheers

You are topping up the inner tube within the dashpot and not the entire dashpot arn't you?

[Ethel]

When you put the plunger back in it displaces oil. If you filled it to the top of the inner tube it's going to overflow & run down into the engine intake. Jimnali & Doddy offer good advice, and you'd know if it needed oil because it'd run like a pig when you tried to accelerate.

[tiger99]

Overfilling is harmless, but pointless, as it leaks between the inner and outer tubes and gets ingested and burnt by the engine.

There is no leak path for the oil, if it is at the correct level, as the bottom of the inner tube is closed, so it ordinarily does not need topping up very often. Once a year should be sufficient.

[Hammerdown]

I'm unscrewing the black plastic cap, gently pulling the plunger up to the point where I can move the cap over to see inside and then topping up to the step. I then gently push the plunger down and screw the cap back down. I'm not getting any oil coming out of the top. It seems to need topping up every week. It seems to work OK, so I guess it's not a problem. If I don't top it up for a long time then the throttle goes very rough and frequently cuts out when coming off the throttle.

Thanks

Oh. Scratch that. I'm over filling it after all! And yes it was coming out of the top. Just checked the exploded drawing in the Haynes manual and can now distinguish where the piston ends.

Edited by Hammerdown, 11 August 2012 - 05:51 PM.

[tiger99]

You will probably now find that it only needs topping up every few years, but it should be checked at every service interval, because the manual says so. That also ensures that it is not forgotten entirely.

[dklawson]

Not to worry. Over filling with oil is very common. As you have discovered, you are only trying to fill that innermost tube and with the damper removed you only need to fill within about 1/4" of the top of that tube. As Tiger said, the excess has no good way to escape but eventually it will find its way into the intake where it is drawn away and burned.