TOPIC:

I just bought a 84 GPZ 750 and do not have a manual yet. i need to replace the fork seals and need to know what weight and how much fork oil is needed. Thanks, Roger

Per the manual:

245-253cc (8.3-8.6 oz)

Oil level (fork tube compressed without spring) 183-187mm (7.2-7.4 in.)

We run a 50/50 mixture of 10w and 15w fork oil in the GPz750 forks, but I'm 230 lbs and GPzInfested is 255 lbs.

Thanks.

By the way, you can go HERE and download a Factory Service Manual

Thanks.

I think 20W fork oil is the cat's pajamas for street riding. I only weigh 160 but it does not seem too stiff. The stuff that came stock in my KZ750 was 15W and it too soft for me.

I just went thru all of these emotions with my bike!
Instead of installing seals i just used a good set of forks from one of my 83 parts bikes.
As far as the oil goes I went the measuring route.
I used an adjustable carpenters square and removed the ruler and used it to measure from the top of the fork tubes down with spring removed and forks compressed I think its like 7 1/4 inches? I cant remember for sure because it was different from the 83-84 but its all in the manual.
I did it this way because even tho i was pretty sure i got all the old oil out i wasnt positive.

I'm sure an old post, but about to try and smooth out the bikes suspension. Over washboard bumps it rattles my eyes out. Progressive front springs and I think rear shock but man its stiff. I really want a smooth ride so should I try changing the fork oil, and 15w or even 10?

Welcome to KZRider
I approved your post , but you may want to start a new one since this is 12 years old.
Also a post in new members with bike pictures would be nice
Dave