kz750 custom swingarm fab

Patton, if I did say thanks before , Thanks, sending rotors off to truedisk

Blackbansheee,
Will an early 83-84 swing arm bolt up to a 1980 KZ? I can handle the shock mounts, I just don't want to have a bunch of machine work to do... Your up there in the Klondike right? man that looks like a hell of a storm headed your way!

Sorry thats a GPZ swing arm...

bovine,
my guess would be that the gpz arm is narrower than the kz frame inside measurement of 9.250 inches.
so you should just need some thicker bushings on each side.
so when you get a chance measure the width of the pivot tube for the gpz with the dust caps on it.

leon

Bovine wrote: Will an early 83-84 swing arm bolt up to a 1980 KZ?

Check with ZukDave on here. He mounted a '83-85 Gpz750 arm on his Kz650.

Later, Doug

When I did the GPz arm it was an eazy swap.
Trim about 1/16" off each end of the pivot tube.
It's a two peice tube one long and a short about 1/2"
spacer on the other side of one bearing that's what hold's center.
Then just drill the frame hole to fit the GPz pivot bolt.
The bolt is a little to long so I made a spacer to go on the nut end.

Zukdave, what year arm did you use?

'83 model arm then had mount's for the strut's welded on.
Add's 2 1/2" over the stock 650 arm.
I also added 5 1/2" to it for a total of 8" over wheel base
but I drag race mine and you can really feel it on the street.

Leon,

Anymore progress on the original topic?

Later, Doug

Zukdave Thanks, I'm thinking the 2 1/2 " longer swingarm is not going to help bending the bike around corners..
Crap I wonder if one of the 600 swingarms is shorter or at least closer to the stock arms length...I might just stick with the stock arm right now, but I'm not giving up on a lighter unit... thanks for the help1

bovine,
i have found that the original swingarms are such noodles that a stronger swingarm even if it is 2-3 inches longer will not negatively affect the handling and in most cases the handling improves because you now have an arm that is capable of holding the contact patch in much closer contact with the surface.

i do know that my z1r with a 2 1/2 inch over swingarm and 190 mm rear tire handles much better than it did with the stock arm and 120mm wide rear tire. :evil:

although i can't get to all of the edges of the 190 because i would have to drag off a fair bit of hard parts to get there :sick: .
in all reality a 160/170 is plenty of tire,but if you don't have enough strength in the legs of the swingarm to keep the axle in the same plane as the pivot bolt it is going to weave in hard corners.
the frames get alot of attention for ill handling but imho the swingarms are the biggest culprits.
i can't wait until tri gets his stealth overbraced stock swingarm mounted up with a decent tire on his bike.
then see how much it improves the handling of a stock length stock wheel sticky tired bike in the fast corners
:whistle: .


doug,
yessir just a slight amount of progress.

it doesn't look like much.
but when you band saw it out of a big chunk,mill it square,fit and mill to size then sand out (most)the machining mark and layout holes and drill and chamfer the holes it eats up some time :blush: .

but after it was welded in i was pretty satisfied with it.



leon

Banshee, thanks for the in-put... I guess I can't say you haven't done some real world testing of a longer arm on your bike.. I have to ask will the longer arms advantage still be worth it if I retain the stock front wheel and forks? Or is the arms benifits only fully realized with a front fork swap?
I've wondered how much the flexy flier feeling was from the arm or the frame? I know there is a tread or two on here about frame bracing... Any way i'll consider your input and mull over the idea of the longer arm swap more. The swing arm in this tread relly is a nice peice of work, heck for that matter all of the stuff you have on here is pretty nice work.. Thanks Again!