KZ550C LTD Fork Oil Measurement.

DANGIT! I posted the wrong file. The file above is my reorganization of the original. Here is what I started with

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That's pretty wild. I wonder if motor oil is the same way. I've tried different brands of the same weight in my leaky car, and some brands leak out way faster, as if the viscosity was thinner.

Thank you for the chart.

Motor oil does vary from the viscosity printed on the bottle, and the viscosity does change as the oil ages in the engine. An easily noticeable example of this is how shifting gets progressively worse between oil changes. I call it "notchy" shifting.

When shifting is no longer smooth, I adjust the clutch and change the oil. Smooth shifting again.

Since this exact subject has been brought up in this other thread, I want to put a link to it here.

www.kzrider.com/forum/5-chassis/595286-1...l-level?limitstart=0

The_Proletariat wrote:

loudhvx wrote: I think this has come up a few times in the past, and there was no resolution that I can recall.

It does seem inconsistent that the C model has such a high volume of oil, but such a short height-clearance measurment.

It has. There are a couple threads about this on this forum, and on other forums. Some suggest to use the height measurement, some suggest to use the fluid volume measurement.

I can offer my experience, perhaps this can be some resolution.

I rode for a week with the specified height measurement of 14''. I was afraid to ride the bike. The front end was very tight and very twitchy and there was almost zero weight transfer when braking with the front brake. The ride was terrible and I was afraid to lean in case a bump in the road upset the now nearly rigid chassis.

I drained the oil and refilled with 300ml of oil. Yes, over the spec but I can measure nearly exactly 300ml. I cannot measure nearly exactly 270 or 290 ml and I wanted the forks to be as equally filled as possible.

After this the bike feels much better. Does not bottom out even with my fat ass on the bike but it is tight enough to be confident to really push in turns. Enough weight transfer under braking to really get on the front brake. In the future I will ignore the FSM 14" height measurement and go by the volume measurement.

Possible error in both manuals?
What If the measurement should be 556mm instead of 356mm?

I feel there is a good possibility this is it. A significant amount of oil needs to be added after the initial fill of 270/290ml to reach the 14'' height measurement.

Following this info, today I used 10oz (295ml) of fork oil. The measurement with a fully extended fork and no spring is 19.75 inches.

LouisDePasquale1980KZ550C wrote:

The_Proletariat wrote:

loudhvx wrote: I think this has come up a few times in the past, and there was no resolution that I can recall.

It does seem inconsistent that the C model has such a high volume of oil, but such a short height-clearance measurment.

It has. There are a couple threads about this on this forum, and on other forums. Some suggest to use the height measurement, some suggest to use the fluid volume measurement.

I can offer my experience, perhaps this can be some resolution.

I rode for a week with the specified height measurement of 14''. I was afraid to ride the bike. The front end was very tight and very twitchy and there was almost zero weight transfer when braking with the front brake. The ride was terrible and I was afraid to lean in case a bump in the road upset the now nearly rigid chassis.

I drained the oil and refilled with 300ml of oil. Yes, over the spec but I can measure nearly exactly 300ml. I cannot measure nearly exactly 270 or 290 ml and I wanted the forks to be as equally filled as possible.

After this the bike feels much better. Does not bottom out even with my fat ass on the bike but it is tight enough to be confident to really push in turns. Enough weight transfer under braking to really get on the front brake. In the future I will ignore the FSM 14" height measurement and go by the volume measurement.

Possible error in both manuals?
What If the measurement should be 556mm instead of 356mm?

I feel there is a good possibility this is it. A significant amount of oil needs to be added after the initial fill of 270/290ml to reach the 14'' height measurement.

Following this info, today I used 10oz (295ml) of fork oil. The measurement with a fully extended fork and no spring is 19.75 inches.

That's great. Thank you for the update. That'll help others know what to do.

Deleted by Ed

The manual says 356mm which is 14". The manual (at least one FSM and other 3rd party manuals) have the wrong value for Kz550C which is the bike in question.

This image is from the red base manual which covers the 1979 Kz500. It is from the appendix supplement for the 1980 model Kz550's and has a Kz550C-specific section for forks on the Kz550C model Ltd (which are much longer than the standard model).
As many users found, the measurement is way off, and does not agree with the volume. Different models/years use different volumes and distance measurements, so we are trying to narrow down a workable volume/distance value.




The white base manual (FSM) has basically the same information.

Model ...... Volume .. Height-Clearance Level
79 500B1 : 220cc : 505mm

80 400J1 : 220cc : 505mm
80 500B2 : 220cc : 505mm
80 550A1 : 220cc : 505mm
80 550B1 : 220cc : 505mm
80 550C1 : 290cc : 356mm

81 400J2 : 245cc : 520mm
81 500B3 : 245cc : 520mm
81 550A2 : 245cc : 520mm
81 550B2 : 245cc : 520mm
81 550C2 : 290cc : 356mm
81 550D1 : 244cc : 517mm

82 400J3 : 245cc : 520mm
82 500B4 : 245cc : 520mm
82 550A3 : 245cc : 520mm
82 550B3 : 245cc : 520mm
82 550C3 : 290cc : 356mm
82 550H1 : 234cc : 489mm

Loudhvx -

Very interesting; I stand corrected as I now see the supplemental information for the “C” model. Does the bike in question have the air adjustable forks? Ed

650ed wrote: Loudhvx -

Very interesting; I stand corrected as I now see the supplemental information for the “C” model. Does the bike in question have the air adjustable forks? Ed

yes, I believe that is when all of the 400/500/550 family forks changed, when they switched over to air.