Rear Suspension Question - 1983 KZ 750 LTD - Omaha

I have a 1983 KZ 750 LTD that I bought last fall. I have limited experience with motorcycles and none with a UJM like the KZ 750 LTD (my other motorcycle is a Ninja 250R) so it's hard for me to tell what's "normal" and what's "not normal" for the bike.

The rear suspension is fairly squishy. If I push down on the tail section it compresses relatively easily and rebounds without any bouncing. If I do the same thing on my Ninja 250R the tail section doesn't even compress. So there's a night and day difference between the two bikes.

The rear suspension of the KZ 750 LTD is set on 4 which is the firmest setting, but it sure doesn't seem very firm.

So my primary question is what's normal for this bike and what should I expect?

My secondary question is what part(s) are likely to need replacing and whether the stock parts are still available and if so are they desirable?

Based upon the info available in this thread it sounds like the stock components were not very good. kzrider.com/forum/5-chassis/570782-rear-...advise-needed#570785

Gary

According to the parts diagram on Kawasaki.com the rear shock for an '83 shaft drive KZ 750 LTD (part number 45014-1203) is cancelled or no longer available. Unless that's been superseded by another factory part I guess that only leaves the aftermarket.

Gary

First off, you are comparing the older suspension to a modern suspension. They are going to be completely different. The Ninja suspension is tuned for a sport bike and the older KZ is not. The older KZ is going to be softer just due to it's age and possible worn out. Ride it and se if you like it, if you don't like it there are numerous options in aftermarket shocks for it.

The very first thing you throw away on any Japanese motorcycle are the stock rear shocks!!!

Stock shocks would be better used as pogo sticks, than on a motorcycle!!

They have been getting better over the years, but still are nowhere near what a good pair of
aftermarket shocks will do for your bike.

Progessive makes a nice shock for the money, and you can select different weight springs to cover
all different weight riders.

Plus they are cheaper than buying another set of non-working OEM shocks from Kawasaki.

If your bike still has the original shocks they have been shot for at least 28 years. The original shocks were arguably the weakest component on any KZ. I have been using Hagons for years and they work great! If you contact Dave Quinn at the link below he will set up a pair to match you bike, your weight, your riding style, etc. Mine are like #4 in the bottom picture in the link.

davequinnmotorcycles.com/cgi-bin/webc.cg...GON_TWIN_SHOCKS.html

Here's a picture of mine:

baldy110:

Thanks for the reply.

In comparing the KZ 750 and Ninja rear suspensions I wasn't suggesting that they should be or would be similar. But I was surprised by just how different they were.

I've ridden the KZ 750 maybe 300 or 400 miles since I bought it. It is well-behaved but then again I've typically ridden it on fairly smooth roads. The front suspension dives a bit under hard braking (but I'd say that's to be expected). I've never had the rear of the bike bottom-out and I don't feel like the rear wheel is hopping around at all.

I do get the sense that there is some shaft-jacking in the rear when coming off the throttle or getting back in the throttle during cornering at high RPMs.

Never having ridden a vintage motorcycle it's hard for me to know what's normal and what to look for.

Gary

Dr. Gamma:

Thanks for the reply.

Gary

650ed:

Thanks for the information and the photo. I saw this posted in another thread and checked out Dave Quinn's web site. I've saved it to My Favorites for future reference.

By the way, that's a great looking bike.

Gary

This probably doesn't matter, but just in case you aren't aware.... The shocks may have a damper adjustment & a spring adjustment. The damper is the numbered dial at the top - turn by hand to adjust The spring adjustment requires the use of a tool. You're supposed to match the damper number to the spring rate. On my 81 650 I have to use a screwdriver bit from the factory tool kit to adjust the springs - I don't have anything else that fits the adjusting hole.

Martin:

Thanks for the reply.

When we were working on the bike last fall we adjusted the damper setting at the top of the shock assembly to the 4 position. We also used a long hex key to adjust the perch setting at the bottom of the spring. We set it at the lowest step. To our way of thinking that pushed the "collar" upwards and compressed the spring giving it maximum preload and the firmest set up.

Putting it on the highest step would have lowered the "collar" and extended the spring giving it more suspension travel and the softest ride.

Hopefully we did that correctly.

Gary

It sounds like you have it at the stiffest setting.

650ed wrote: If you contact Dave Quinn at the link below he will set up a pair to match you bike, your weight, your riding style, etc. Mine are like #4 in the bottom picture in the link.

davequinnmotorcycles.com/cgi-bin/webc.cg...GON_TWIN_SHOCKS.html

quote]

650ed:

I just sent an email off to Dave Quinn re: information and his recommendation re: replacement components. Hopefully he'll have something he can come up with.

Thanks again for the info.

Gary