FAQ? - Changing Fork Oil - '83 KZ 750 LTD Shaft Dr

I have an '83 KZ 750 LTD that has fork oil that's somewhere between 16 and 29 years old. I think it's time to change it.

The fork seals are not leaking but the front end is a bit squishy. I assume part of that is due to the age of the fork oil and part is due to the fact that the air pressure in the forks is close to zero.

Can anyone tell me how to change the fork oil without replacing the fork seals? My buddy that worked on the bike with me last weekend said if the fork seals weren't leaking that he'd advise leaving them as is.

I've referred to the KZ 750 Work Shop Manual (The Bible) but it doesn't cover the LTD Shaft Drive (F1) model.

Any guidance is greatly appreciated.

Gary

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Martin:

I'll take a look at that again later today. I had actually found that topic earlier by doing a search on the web site for "fork oil change" but I was having a hard time relating it to what I see on my bike. But keep in mind I have very little experience with motorcycles and not much experience as a mechanic.

The thing that threw me for a loop initially was that the top of the fork doesn't have a bolt that you can remove. There's a smooth cap/cover on the top.

We had initially come to the conclusion over the weekend that the air valve needed to be removed and the oil refilled using a syringe. But rather than setting forth on that path, I thought I'd investigate that a bit further here first.

The PDF version of the factory manual that I have doesn't cover the F1 model and the aftermarket manual that I have didn't have very detailed instructions.

Gary

I don't think you will be able to withdraw all the fluid using a syringe because you won't be able to get a tube down below the fork cylinder. Doesn't your model have a drain screw similar to that on the KZ650 (see pic)? Ed

650ed wrote: I don't think you will be able to withdraw all the fluid using a syringe because you won't be able to get a tube down below the fork cylinder. Doesn't your model have a drain screw similar to that on the KZ650 (see pic)? Ed

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Ed:

I'll be checking that this weekend.

If it's got the lower drain screw, it is as simple as removing the drain screw on each fork, measuring the amount of fluid that comes out; and then refilling the forks with the appropriate fork oil using a syringe or other pumping device? (Note - the syringe was not to be used to extract the fluid; only for refilling.)

Gary

If yours has the drain screws you remove a screw and pump the old oil out by pushing down and up on the forks with the front wheel on the ground. Do one fork tube at a time including re-filling. If both sides are drained at the same time the forks can collapse down to the bottom. For re-filling you will need to consult the manual. To accurately re-fill you measure the level of the fork oil with the front wheel off the ground and the springs in. The measurement is taken using a dowel or other appropriate tool from the top of the fork tube down to the top level of the fork oil. The correct distance should be listed in the manual. After changing the oil in both sides to that level you pump the forks and ride it a bit then check again and adjust as necessary. Ed

Since your forks are a little different at the top, you may have to use the drain screws. My experience w them is that it isn't real easy to drain the forks there. It seemed more efficient to remove the caps & just dump it out.

I looked at the diagrams for you F1 Ltd-Shaft & the forks have different caps which are held in place w circlips & yours have the air crossover assy. So I'm not sure of the best way to do those.

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Good Fortune!

martin_csr wrote: Since your forks are a little different at the top, you may have to use the drain screws. My experience w them is that it isn't real easy to drain the forks there... each orifice is small. I tried pumping n stuff, but that just made a big ole' mess. It seemed more efficient to remove the caps & just dump it out.

However, I looked at the diagrams for you F1 Ltd-Shaft & the forks have different caps which are held in place w circlips & yours have the air crossover assy. So I'm not sure of the best way to do yours.

PS: if you need a manual, get one for the KZ750 Shaft models. It'll say Shaft on the cover. Make sure it covers at least 1983. Kawasaki factory manuals have a model application chart on the back cover, so make sure yours is listed.

Martin:

Thanks for the info.

I just ordered a workshop manual through Ebay earlier today. It should be here next week.

Gary

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Patton wrote:

Good Fortune!

Patton:

Thanks for the info.

I just ordered a workshop manual through Ebay earlier today. It should be here next week.

Gary