1977 Kz650 Bobber Project

Hi all!
New to the site and the world of vintage bikes. Motocross racer and own Kawasaki bikes so figured I'd stick with my brand when looking for a project bike. I picked up a '77 Kz650 with 18k miles off of Craigslist a few weeks back after falling in love with the looks of bobbers. I picked it up non-running. It had sat for 5 years; I was nervous what I was getting myself into. Pulled the carbs and cleaned them along with new gaskets, picked up a new battery, and cleaned the tank. Flooded the bowls out and she started right up! I wanted to make sure it would run and drive before I started the build so I rode it for about 10 miles.
Got her washed up then started the tear down. Everything came apart so easy! Currently sitting in my barn as a roller. I went ahead and ordered the TC Bros Universal Weld-On Hardtail Kit, TC Bros electronics oil tank and battery box, POD filters, and some other odds and ends. Having a buddy who works at a fabrication shop weld everything up for me seeing how I don't trust my own welding.
Plans:
1. Hardtail and small extension
2. Lower the bike a bit
3. Source larger spoked wheels
4. Forward controls
5. Digital speedometer

I do have a few questions for you enthusiasts:
I want to use a different tank, but the triple back bone holds the tanks up to high. If I cut the outter bones away, would I have to somehow brace that or would it be okay with just the center?
How hard is a rear disc conversion on one of these?
Looking for a 19" front and 18" rear spoked wheels. What wheels will work on these?

I'm sure many more questions will arise within the next couple weeks when the build really takes off!
Thank you so much and look forward to hearing responses!

If you cut the 2 backbone tubes you will probably get killed when the bike collapses while riding. Other than that, there shouldn't be a problem. :S Ed

Post up some pictures of what you started with (or where you are now) You know those 77's are beautiful bikes, hope you aren't chopping into a survivor

Ed,
I've seen some guys who have cut the outer two bones and only went to single, but I didn't really understand how they did it. Do you have any suggestions on what I could do or if there is a company making tanks that fit over the outer bones?
Thanks

Bluezbike,
I'm more into the bobber, rat look than the stock KZ look. I know there are some fanatics over these bikes and I don't blame them, they are beauts! I'm hoping others will like my taste when I'm done with it as well though! Attached are pictures of the bike. I picked it up off of a guy who had it stored under a tarp in a worn down shed (literally daylight coming through the roof!!!)

mkimmel166 wrote: Ed,
I've seen some guys who have cut the outer two bones and only went to single, but I didn't really understand how they did it. Do you have any suggestions on what I could do or if there is a company making tanks that fit over the outer bones?
Thanks

I have seen guys remove the front brake and use the rear sprocket (which of course gets chain lube and slippery) as the rear rotor. That does not mean it is a good idea, and nearly every nitwit that does that never actually rides the bike. Just like removing the front brake, which provides 80% of the stopping power, cutting the backbones is a really bad idea. The stock fuel tank already straddles the backbone very well so that it sits pretty close to the engine. If you want to use a different style tank you may have someone modify the bottom of the new tank to resemble the bottom of the stock tank. That way it would sit low without compromising the structural integrity of the frame. Ed

All good on what you want to do, I would really support Ed on keeping the frame top tubes intact. I also own a 77 KZ 1000 and it is considerably more flexible than my 650, Kawasaki really worked on beefing up the frame and they did a good job of it. , A successful bobber is one you ride, and ride many times, keep it safe. If it is only for a different tank you might use the tank you have and have someone cut the bottom off and build on a different top section.

I use a peanut tank on my bobber, this should give you an idea of a way it can be done. You are basically going to need to cut the frame and start with your rear extension, then work out the angle for the backbone then figure additional bracing to your liking. I dont think the stock angle will look right for any tanks other than the stock type ones. I completed this bike in Feb 2012 and have been riding it daily every season since.

You will have to check specs for fitment but I would take a look at 750s in the same year range as your 650, as well as some 650CSRs for a 19" front spoke wheel

Bluezbike,
I didn't even think about cutting the tank to use the stock tunnel and base. I'm actually really considering this now! Either that, or chopping up another tank and putting in a larger tunnel. Chopping the frame didn't sound like a great idea to me which is why I asked here first! Parts will be in tmrw so hoping to get the hard tail fabbed up this weekend!
-Matt

ChicagoLTD,
Thanks for the pics! Definitely gives me a good idea if i decide to go this route. Your bike looks great by the way!

ChicagoLTD wrote: You will have to check specs for fitment but I would take a look at 750s in the same year range as your 650, as well as some 650CSRs for a 19" front spoke wheel

looks like he's already got the 19" spoked wheel

is there a rear swingarm kit like this I can get a link to or is it all custom fabbed? im looking to fit a fat boy tire on my 81 kz550 LTD and would much rather cut frame and weld on a pre fabbed rear hardtail kit rather than fab my own (not that I don't mind a challenge but that's less time working and more time working towards getting her street ready ) Please any info and tips and tricks and links would be greatly appreciated! Also if anyone has the SET of ignition coils and also looking for the IGNITER, send me to whoever has or knows somebody who might have these parts! thanks and ride on guys!