KZ650 Whats a good front end upgrade?

Hey everyone I'm pretty new to this site and been finding lots of good info. I have a question about upgrading the stock front end on my 1980 KZ650 E1 to a newer style Ninja or ZX style front end or just something that will be better for my fat arse! haha Is there a good reference out there for what ones might be an easy swap with the same headset or just need bearings swapped and still be close to stock ride locations? I've tried searching this site but haven't found what I'm lookin for.

What problem are you trying to solve?

Whats a good front end upgrade?

A new tire, especially if your current one is more than 5 years old.

Welcome to KZR!

This might sound weird coming from me, considering that I have an upside down front end and monoshock rear on my bike, but you need to consider what 650ed and rstnick are saying.

First and foremost, don't think that the original front forks aren't up to the task. Keep in mind that they are 32 years old and probably haven't been serviced like they should have over all those years. Almost every used bike that I have ever ridden could use a fork oil change and springs that were the correct rate for the rider. Those two things alone will make an enormous difference. Before you swap the forks, give Race Tech a call and see what they suggest for springs, oil and maybe an emulator kit for those forks.

Switching to a USD fork is not necessarily an easy conversion. You lose ride height and cornering clearance. You still need to change to the correct springs and oil. Yes they are more rigid, but they are made for lighter bikes with stiffer frames, and 150 lb riders. Also you lose some turning radius and need to make provisions for keeping those fat fork tubes from banging into your tank.

If you consider all of these parameters and still want to make the change to a USD front end, then I won't criticize you for it. Actually, I'll be happy to advise, but I don't want you to think that it is easy or straightforward. Every change begets another change, and a properly sorted bike is the result of a comprehensive suspension setup. Just adding a stiffer, and more adjustable fork will not necessarily improve your bikes ride or handling.

I started a post called what front end did you use? add your question on it if you dont mind i would like alot of the guys who have done the swap to post their data on it it might help the rest of us who are trying to figure out which one to use

Good points guys. I'm really mostly interested in the USD forks for the look I guess. I'm 240 so its a bit spongey in the front and rear but you're right I probably just need to rebuild the forks with better springs and maybe that gold valve I saw on that racetech site. I was trying to see if there was ANY fairly direct swap but I should have figured that was a far cry.
Thanks for the input I will talk to racetech and see what they come up with. I will also check that thread and see whats been said too. I'm all about trying to make this bike what I want it to look like and hopefully perform like. I've never been a stock guy, I'm a car guy at heart but forced by gas prices to start looking into cycles, and I've gotta say I'm loving it so far.