Harsh Ride ?

Been riding my 77' KZ1000A I've put together a while back with a lot of help from the Forum members. So far have riden the bike a little over a 1,000 miles and installed new tires 19F/18R . Bike rides real harsh. Seems to feel every bump in the road. Bike still has the stock fork spring ( 10 wt. fork oil ) and stock rear shocks even though they are 12" in length, which works for me due to my height. I only weigh 170 lbs. with gear on so not a heavy rider.

So my question is Fork Springs and Shocks. Are these that are on the bike now just plain worn out and need to be replaced ?

Recommendations ?

Too much fork oil? I rode with my stock springs 30 years until I got progressives.
Steve

Change the fork oil; use the instructions in the Kawasaki Service Manual to do it correctly. I have the original springs in mine and they still work fine (I've owned my 1977 KZ650-C1 for 40 years), but the fork oil must be changed on a regular basis or the forks will behave poorly.

If the rear shocks are original they are worn out. The stock shocks on the 1977 KZ's were marginal to begin with and quickly went downhill from there. Consider getting a set of Hagon rear shocks. Ask if you need more info. Ed

Whats your tire air pressure ?

When I rebuilt the forks earlier with new seals, I filled the fork tubes with approx. 175 cc per FSM ? Also, my air pressure in the tires are set at 30 lbs. ( F ) and 36 lbs. ( R ). Do not know the age of the rear shocks but assuming they are old. Certainly not the right length but work for me. I have them set at 2-clicks of the compression adjustment at the bottom of the shock.

I wouldn't rely on using a volumetric measure of the fork oil and would not use 10w fork oil. Using a volumetric measure can cause problems if any old fork oil was still in the forks when you added the new fork oil. Doing that could result in too much fork oil in the forks.

Instead, you should follow the Kawasaki Service Manual instructions and measure the fork oil level from the top of the fork tube. Be sure to do this with the springs in the forks, and do one side at a time with the front end off the ground and the forks fully extended. See pages 186 - 187 in the manual for details on doing this task, and notice it does NOT recommend 10w fork oil; that fork oil is too thin. If you do not have a manual see the link below. Ed

www.kzrider.com/modules/ServiceManuals/K...Service%20Manual.pdf

What fork oil wt. would you recommend ?

I am not familiar the the 650 specs, but 30/36 seems like too much pressure. It is best to stick with Kawasaki's recommended tire pressure, unless the tire manufacturer recommends differently. Be aware that the pressure listed on the sidewall is the maximum allowed, and should not be used unless you have the bike at the maximum passenger and luggage load AND plan to spend a long time at the bike's maximum speed. In other words, ignore those numbers.
You say you have shorter shocks on the bike. Were they designed for a bike the same weight as yours? If they were designed for a much heavier bike, they will ride harshly.
+1 on 650Ed's comments concerning fork oil.

When you put in the fork oil you have to pump them then measure the level. Easy to put in too much.
Steve

kzdcw wrote: What fork oil wt. would you recommend ?

Did you bother to look at the link I provided? Ed

Ed, I did look at your Link as well as my FSM which is for the KZ1000 revised Sept. 6, 1977. My page # 185 show a chart for a KZ1000-A1 which is what mine is, shows the Fork Oil capacity after dismantling and dry to be 170-178 cc. And that's what I poured into each fork tube.

Only discrepency I did discover is that I used 15 Wt. Bel-Ray fork oil instead of the recommended 10 wt. So that might be a little problem there ?

Tire pressure may be a little high too as the FSM says 28 lbs. ( F ) and 32 lbs. ( R ) ?

And again the rear Shocks look identical to the Factory ones but are shorter. So who knows where they are from and what weight they designed for ?

If you don't pump them, they will hydrolock.
Steve