'78 KZ650SR Fork Oil?

I've just finished replacing the fork seals on my 1978 KZ650SR. It took a little longer than expected, but we managed to get it all back together again. Now I'm ready to top it up with new fork oil and I realize that I don't know how much to put in. D'oh! I feel like I've searched around every dark corner of the internet but I can't find the fork oil spec for the 650SR. Does anybody out there know how much fork oil to put in a '78 KZ650SR? I'm not really sure if it would be the same amount as the KZ650.

Fork oil quantity is not overly critical as long as there is enough oil to cover the damper passages. I think the SR forks are very similar if not identical to the standard model 650 forks so using the same oil amount should be fine. One alternate tried and true method of figuring out oil level is to compress the forks with the springs removed and then fill them to about 6" from the top. The amount of oil determines the amount of trapped air in the forks at full compression, and said air acts as a supplemental spring, and a 6" air gap should be plenty.

The owners manual, the factory service manual, and any decent aftermarket manual should have that info. A factory manual is best, and almost a necessity when owning one of these old bikes.

The FSM supplemental section for 650-C, page 247, step 5.: Refill with 182-191 cc of fresh SAE 15w oil.

Thanks everyone! I'll give the 182-191cc a try.

I HIGHLY recommend using BelRay 15w fork oil. I've been using it in my KZ650-C1 for more than 35 years and it works great!..Also, you do need to buy a Kawasaki Service Manual, but until you are able to get one here's the relevant info for your bike from the manual. Ed

Never seen a manual recommend measuring the oil level with the fork extended and fork springs installed. Modern forks almost always measure with forks compressed and springs out.

The FSM for my 80 LTD 1000 say's forks extended springs installed, to measure oil level, that's how I did it last year, & they are perfect
Pete

Nessism wrote: Never seen a manual recommend measuring the oil level with the fork extended and fork springs installed. Modern forks almost always measure with forks compressed and springs out.

I've seen different ways of measuring the fork oil level specified for different models in the Kawasaki Service Manuals (FSM). For example; the FSM showing the specs for the 1978 KZ650-D1 states the spring should be IN and the measurement from the top of the fork to the top of the fork oil should be 412mm.

The FSM showing the specs for the 1979 KZ650-D2 also states the spring should be IN and the measurement from the top of the fork to the top of the fork oil should be 412mm. HOWEVER - that SAME FSM shows the specs for the 1980 KZ650-D3 and states the spring should be OUT and the measurement from the top of the fork should be 433.5mm. So the FSM shows different fork oil level measurements depending on whether or not the spring is in or out. This makes sense since when it is in the spring displaces some volume of oil which then causes the oil to rise to a higher level. I believe this makes it important to know for sure if the specified measurement from the fork tube top is to be taken with the spring in or out, otherwise it would be easy to over or under fill the fork oil. Fortunately, the FSMs that I have seen always specify whether the spring should be in or out.

One other note - all the KZ650 manuals I have seen (I have 4 different FSM covering 14 different KZ650 models) specify that the bike should be raised so the front wheel is off the ground and the front forks should be fully extended when measuring the fork oil level. There must be a different approach for modern forks if they must be compressed for the measurement. Ed

Thanks everyone. I'll use that 412mm measurement when I get back to this later today or tomorrow. I think my big misunderstanding was that KZ650D is the same as KZ650SR, so maybe I could have found that spec if I had known that while digging around online. Also ordered a manual today which should arrive next week.