squishy forks

You can use schedule 40 PVC, that is what you get in the Progressive Springs box for a spacer from the factory, with mine I'm pretty sure it even said for me to cut an inch off each one for my bike.

The ones I got weren't even cut squared off on the ends so I did some up in a lathe real quick and used those instead.

schedule 40PVC, ok. i will do this and report back! thank you

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martin_csr wrote:

650ed wrote:

martin_csr wrote: You can get some Progressive springs. I've seen fork springs at Z1Enterprises.com but can't seem to locate them.
If you get new springs, it might be a good idea to upgrade the rear shock absorbers as well. Otherwise, you may end up with a firm front end & a mushy rear.

I rebuilt the forks on my 81 650 & used the specified 10W fork oil. The springs were well within the service limit. I'll use 15W next time, but the bike probably needs a suspension upgrade.

I read this and thought - I just checked the genuine Kawasaki KZ650 manual this morning and verified that it specified 15W fork oil before posting my answer in this thread, so why would Martin say "specified 10W fork oil?" Was he using a Clymer or Haynes manual? Then I though - just for once, before I shoot my big mouth off disputing someone's information let me do a bit more research. Here's what I found. The Kawasaki KZ650 manuals are all over the place regarding the fork oil weight. In them I found multiple places where SAE 10W; SAE 10W20; and SAE 15W were specified. So Martin's assertion of "specified" is also true. Personally, I've always used 15W Bel Ray fork oil and have been very please with the results. Ed

The "specified" comment was in regards to the 81 KZ650 - as mentioned in the reply. And the info is from the genuine Kawasaki factory service manual - it says to use SAE 10W (pg 2-21 Table 2-12). Next time I'm using 15W.

I'm thinking my forks dive a bit too much inspite of the fact I put progressives and 10w in there.
I bumped this thread as my manual, a shop manul, but oddly the whole thing is in metric, and constantly having to convert, says 10W also
I'm running a windjammer, should I skip right to 20w?
thanks

You could go right to 20w or you could give the 15w a try. Either way, if you use Bel-Ray, you can mix the different weight fork oils to fine tune the ride. So if you found 15w wasn't stiff enough and 20w was too stiff you could mix half of each and tune the ride someplace in the middle of the two. Ed

Might need a couple of things with running the Vetter. First how much pre-load is there on the springs. When the bikes front end is all the way up, full fork extension, how much do you measure for distance for the fork cap to tighten down on the spring? An additional 1/2- 3/4" here might help alot. I use about spacers cut to about 3 1/4" on mine, so the springs and spacers are level with the top of the Tubes. Also I run 15w fork oil, but it is a different model. Its the 82 KZ 1000 LTD with 38mm forks, Vetter also.
I also just put in Race Tech Emulators, with Progressive Springs, and a Fast from the Past Fork Brace. Its a whole different front end.

Try some 10/30 0r 10/40 synthetic motor oil in there in place of that 10w