'78 KZ650B cafe/street project. Nuttin fancy...

So I checked out the old fork oil I drained out of the tubes and it seems to be much heavier than the 15W fork oil I used… What weight should I try next? 20? 30???

Thanks!
Richard

No updates on the bike other than I've logged a little over 300 miles in the past week and all is well...

I did make this at work though and thought I'd share...









I'm really happy with how it turned out, but the only problem is I made it just big enough that it rubs on my painted handle bars...

Oh well...

Nice job on both the bike and the key fob.

Rainman wrote: Nice job on both the bike and the key fob.

Thanks Man!

I've put a little ove 1,000 miles on it and haven't gad a single glich! (other than the front dives a little and bounces some... ) I planned to paint it soon, but am having too much fun riding!!!

-Richard

If u need to stiffen up the front end a little,measure the inside diameter of your fork tubes,cut two 7/8 inch pieces of PVC pipe of the appropriate diameter and slide them in on top of your fork springs.Poor boys version of fork emulators.Actually the proper (factory) way to mount NEW Progressive springs in my Yammi Radian.Works like a charm.bj

hocbj23 wrote: If u need to stiffen up the front end a little,measure the inside diameter of your fork tubes,cut two 7/8 inch pieces of PVC pipe of the appropriate diameter and slide them in on top of your fork springs.Poor boys version of fork emulators.Actually the proper (factory) way to mount NEW Progressive springs in my Yammi Radian.Works like a charm.bj

Thanks BJ,

I thought about that, but the istallation instructions from progressive said that it wasn't need for this model... I will give it a shot anyway because it's cheap and EASY...!!!

No major progress, but I did put a new sprocket set, chain, front and rear wheel bearings and a lot of the "shimmy" I had has gone away... I think I will go ahead and add the shimms to the front springs and see if that gets rid of the rest of it. The only other thing I've noticed it that with the new bearings in the neck it is much looser when laid way over on sharp corners. I may try adding a dampener to the trees???

Anyway, here's a couple of images for the Oics Whores...
















Thanks!

The lack of dampening in the forks could be related to the type and amount of fork oil you're using. I use 15w Bel Ray fork oil in my '77 and the forks work great - no bounce, controlled damping but not too soft even when riding 2-up (I weigh just under 200 lbs; my wife is about 110 lbs.) My bike has the original fork springs and they still measure well within the service limit. You can mix different Bel Ray fork oil weights to fine tune the damping to meet your requirements. I don't know if you have the original KZ650-B2 forks, but if you do I can give you the fill level if needed if you want to experiment with different fork oil weights.

Although it could be related to lack of the fork dampening, the remaining shimmy could be a couple other things.

1. Tires - My bike developed a consistent bad speed wobble at 90+ mph; I replaced a bunch of stuff, and this helped a little, but in the end it turned out to be the tires. My tires (Michelin Macadams) looked great and only had about 6k miles on them. They were mounted and balanced properly and had no visual signs of anything wrong. I replaced them as a last resort when nothing else I did totaly eliminated the wobble. The new tires, Pirelli Sport Demons, completely eliminated any hint of wobble all the way up to an indicated 120 mph. This made me a very happy camper!

2. Steering stem bearings (but I believe you replaced those) - the old ball bearing races on mine were shot and caused a low speed (< 30 mph) wobble when I let go of the handlebars. Tapered roller bearings totally fixed that.

3. Swingarm pivot bushings/bearings - my '77 had bushings that allowed a little play when tested. New bushings eliminated the play and somewhat reduced the speed wobble mentioned above. If you haven't done so, you may want to test the amount of play between your swingarm and frame. A little play there can create wierd handling issues.

4. Shocks - Looks like you've got that covered already.

At what speed does the shimmy happen? BTW, those are really cute kids! Be sure to spend plenty of time with them as they grow up very fast. Ed

Thanks for the advise Ed. I too am using 15W Bel Ray fork oil. I also have brand new tires, but they are cheapo Shinkos... I''ve been very happy with them , bu I guess they cold be causing some of the issue. I will try the shims and report back.

Yeah, we've got some good kiddos! We shipped em off the Montana with thier granparents for a couple of weeks and miss them already...

how are those rear shocks holding up?

arldavey wrote: how are those rear shocks holding up?

No complaints so far...

Hey, if you addressed it already sorry. I have a question about the seat, did you have it done or DIY, that's about what I had in mind for my seat. How did you fasten the leather on the bottom? Also, looks like you cut a bit off of the bottom, the frame is exposed there I can see? Nice work.