kz650 Stiffer Fork Springs

I am looking to stiffen up the front a little, but have only found the progressive springs for the kz650. Are there any other places to look or springs that will swap in from other bikes?

From my list of suspension places:

www.progressivesuspension.com
www.racetech.com
www.hygearsuspension.com
www.aftershocks-suspension.com
www.gpsuspension.com

A few people have told me to switch to a 30 weight fork oil to stiffen up the front, just haven't found any on the local shelves so far.
I know you canorder through some of the suppliers.

If you haven't done so already, before you change the springs I would suggest you establish the current baseline. As a starting point; what weight fork oil are you currently using and when was it last changed; have you measured the length of the stock springs to see if they are beyond (less than) the recommended service limit? Changing springs without understanding the existing conditions makes it a bit of a crap-shoot that you'll get the desired effect. Ed

SAE 30W worked well for me!

change the fork oil...stick a 1" peice of p.v.c ona fender washer on top of the spring...and put air caps on it...you'll think you got a new front end.....a great tire and 36 p.s.i make one hell of difference too....

I was told by plummen to run 30 weight synthetic motor oil, it will stiffen up the front end, so im going to do just that on my z1 rebuild.

I've never tried this but I was reading a book about motorcycle chassis tuning and they were talking about how if you add extra oil to the fork it will displace some of the air and make the compression stroke stiffer and make the fork rebound faster. This is of course assuming that the fork is airtight and none of the seals leak. It makes sense but like I said I've never tried it. For all I know it will blow all your seals. Anyone else try this??

i screwed up in a metric,oz, conversion once ......:laugh: and it was tooo much:blush: my forks would not go down any:dry: ...your theory is true in my book but i did not think to go heavy on the oil a tadd...i like the idea...was it kevin camerons book you read?

becker, i remember reading that also but i cant remember were to save myself. In theory it makes sense, but i would think the extra oil would blow the seals the first time you had to stop suddenly or if you did a wheely. On the other hand, my front end on my 900 is shot, so im putting in new progressive springs, all the seals and such, im also going to run the 30 weight synthetic motor oil. I will let you guy's know how it works out. I need stiffer fork springs because im running a sidewinder exhaust, and it is a really tight fit between the front wheel and the head pipes, i really dont want the front weel to lock between the head pipes.......that would be a vey bad thing for me or the bike.

if you had the time at progressive site compare the different lenghts of springs for different applications.:ie
if you have 36mm springs then you have kz650,kz750,gpz750 springs to choose from.also like some others have suggested use a little heavier oil and also the pvc tubing.in my front forks i use 20w oil and a 3" piece of 1/2 pvc tubing w/fndr wshrs.the front end is stiff but i prefer very stiff front end.as also we have two very different applications also.hope this or other suggestions work for you.
Regards Paul

Thanks for the help and the links. I was trying to avoid buy new springs outright if I could, I have too many other things popping up (like my slippery clutch) that are going to drain my monthly budget. I'll see if I can get some fender washers that will work.

As for oil, I put in 15wt when I redid my seals about 300 miles ago. Is the 30wt synthetic you are talking about just a motor oil or did you use an actual fork oil?

My problem is that my rear suspension is stiff and the front is stock so in the corners it starts feeling a little odd when I cross over some of the bumps.

On the air caps, did you just drill the stock caps or where there caps that came that way? Mine have the recessed square drive on the top caps.

Thanks for the help so far!