to buy or not to buy? 1978 kz650C

well i really want the rear disk and mags on my 78kz650b
but conversion seems time consuming and more work.

so I have a guy who has a 1978 650c does it make sence to buy it (1,100) switch all my mods over to it.
then i could sell my 650b

I have a 1981 650de sr motor in the 650b with 4into 1 kerker-stage 3 carbs-kn pods dyna 2000 electronic ignition-fork handle bars-chrome master cylinder-braided brake-lines-aftermarket plug-wires
bar end mirrors.

i belive that could all go on the 650c direct swap.
will the 4-1 kirker fit right on the 78 650c motor?

i belive i could still get 800-1000 for my 650b so it would be more about time. and weather the 81 650sr motor is better in my 650b- I coud swap that to but only if its a more performance motor?

any help thanks

They probably have different carbs. The '78 would have started life with a couple more hp than the '81, but who knows what power either bike has after 30+ years. The front brake master cylinder for dual front disk brakes is different than the one for a single front disk (different diameter innards to move more fluid). I would properly tune the '78 and ride it for a little while to see how it performs compared to the one you modded. Then you can decide if the mods are a plus or minus performance-wise and if you want to apply them to the '78. Ed

thanks
i do have duel disk brakes on the 78650b puss a aftermarket brake master so that would be fine.
i just hate to buy a hole bike, but the bike i have doesnt have top triple t
and prior owner cut spokes, so i would have to get spokes and top triple t and its back up and rideable, but it has spoke wheels and drum rear with duel front disk,.

am i waisting money bying a hole nouther bike for 1100 just for rear disk and mags?

I guess it depends on the condition of the second bike. If it's nice you might keep it and use it rather than transferring parts from it.

If the only thing you really want from it are the wheels and disk brake in the rear, I would think you could do this for much less $$$$ by picking up the wheels, rear brake and swing arm from a C model. I include the swing arm as it will have the bracket for the rear brake already.

Here are some mags in the for sale section

kzrider.com/forum/23-for-sale/503564-kz650-mag-wheels

You can definitely get the parts you wanted for less than buying a whole nother bike. Post something on the Wanted section.

Also, why do you want a rear disc? It doesn't help you stop any better than the disc and the whole setup weighs noticeably more.

mtbspeedfreak wrote: You can definitely get the parts you wanted for less than buying a whole nother bike. Post something on the Wanted section.

Also, why do you want a rear disc? It doesn't help you stop any better than the disc and the whole setup weighs noticeably more.

Ever wonder why....

Who needs a rear disk when you can power out of a corner like that? :lol: :lol:

650ed wrote:

mtbspeedfreak wrote: You can definitely get the parts you wanted for less than buying a whole nother bike. Post something on the Wanted section.

Also, why do you want a rear disc? It doesn't help you stop any better than the disc and the whole setup weighs noticeably more.

Ever wonder why....

Attachment Eddie_Lawson_Kawasaki_2012-02-17.jpg not found

Obviously the stock swingarm, disc, caliper and rim. My fault....

Kawickrice wrote: Who needs a rear disk when you can power out of a corner like that? :lol: :lol:

650ed wrote:

mtbspeedfreak wrote: You can definitely get the parts you wanted for less than buying a whole nother bike. Post something on the Wanted section.

Also, why do you want a rear disc? It doesn't help you stop any better than the disc and the whole setup weighs noticeably more.

Ever wonder why....

Attachment Eddie_Lawson_Kawasaki_2012-02-17.jpg not found

mtbspeedfreak wrote: "Obviously the stock swingarm, disc, caliper and rim. My fault"

Right - custom rear wheel, swing arm and brake. So since they could use any kind of brake, why would they chose disk over drum? Seems to me since they were going all-out to win races, and money was not a serious obstacle, they would select the components that would give them the best chance of winning races. Maybe I'm wrong. Maybe they couldn't afford a drum brake.

We're over complicating things here...

The stock drum brake wire wheel, drum brake and drum brake specific swingarm are lighter than the stock mag disc brake mag wheel, disc rotor, caliper and disc specific swingarm.

I've locked up my rear drum wheel on more than one occasion so the performance benefit of a stock disc brake conversion is negated by the increased weight difference.

Of course when money is no object, like an AMA superbike when you run true magnesium alloy wheels in a race setting, yes they have rear discs. And there's also a reason why you can't get drum rear brakes after '76.