Widening a frame for a wider swingarm?

[dixiethedog]

This isnt really so much a help question,as Ive my ideas and other people have theres. Just more a what do you think type of thing?
I was looking at the great new site (which im a member)aircooled suzuki,in the project section where a very talented builder is fitting a 200 section tyre to his bike. He's done a great job of cutting the frame tubes and welding bits in to allow the chain to move out and not hit the frame. Top notch work in fact.

http://www.aircooledsuzuki.co.uk/viewto ... 0&start=40

Check it out. Its a great site for things non Kawasaki. lol. And old.
I made comment that his way looks like a lot of work. Not in a negative way,just an observation.
My way,which might sound crap (but works),is to cut the frame cross braces (centre stand brace etc)(side to side ones),whop a jack in and wind out to the desired width,then weld to hold things in position. This will splay (is that the right word)the frame side out. Next up,drill the existing swingarm pivot bushes out and remove,put the swingarm into position and then add newly machined swingarm pivot bushes (boss')to the frame,put your new swingarm spindle thru to position and weld the bushes in.
Sit back with a cuppa and think what next to do. A couple of hours graft.

Does anybody else have any thoughts?
My mate recently did this on his bike to fit a standard zx9r arm in. (z650 frame)
I'll try to get some piccies.
Im waiting to see if a z650 std frame is coming my way in the next few days,and it will get its tubes cut!

[nanno]

If you simply force the tubes apart they will form a v or A shape, i.e. the swingarm bores will not be exactly level anymore and as they are precision ground to size, cutting the frame rails for chain-run would be the better way to do it. If you don't want that, you could still fit an intermediate shaft, if you put that one on the swingarm pivot, you wouldn't even have to mess around with a chain tensioner.

Of course talking about the angling of the bores, this is the answer of someone who had to take lots of engineering course in college and may or may not be hypocritical. To be fair, it'll probably work, but it's not right in an engineering way of looking at things.

You may want to ask the same question on OSP, as there's a couple of people there, that have faced and solved this issue before. And see some other ways of tackling this than the Lord Strangewayz way (which is bl** awesome btw. but it's a little work).

Cheers,
Greg

[yantosh]

i did it the stangeways way with my Z650, fitted new bosses to accept a blade spindle, one boss with an internal hex . like Nanno says, if you just cut out the bracing and jack the frame apart the spindle holes will move out of line and you won't get the spindle through them both (found out to my cost with a Kat frame )

[dixiethedog]

Thank you both for comments.
I figured that the way Ive done it and some of my friends have too,that boring the old boss' out,with the frame widened,placing the swingarm into position,and then welding in the new boss',with a swingarm spindle inserted would be ok. Ive been offered the use of a frame jig for a few hours,so I'll bung the frame on that,make a jig fitting to allow for the spindle before mods are made to anything,and then go for it. With it done on a jig I should be able to keep things straight and even as needed.
When I make a start,i'll be armed with my camera to show you's.

Yantosh,I thought if youve used a zxr swingarm you would have needed the frame widened an inch or more?? Did you narrow the pivot point?
Ive a H**** swingarm here for somebody thats been shaved down on the milling machine,with the bearing recess having been bored further into the arm,to allow for the narrowing,but its a lot of work still.
Its not always easy this motorbike engineering stuff. Especially when like me,Im an idiot!

[zmaxmotorsports]

Id just find a swingarm with a narrower pivot tube,or just narrow the pivot tube on the swingarm myself.
As easy as it is to come by Suzuki swingarms I personally don't see the need to try and widen an old z/kz frame,theres enough other things that these frames that need without adding that to the puzzle

[yantosh]

yeah Dixie i had to widen the frame, was no point finding a narrower arm as i was fitting a 5.5" wheel

[dixiethedog]

I was down at my mate house this afternoon who's widened his frame the way Im suggesting. I forgot my camera. Doh!!!!!
I wouldnt care he has pulled it down for powdercoating and I could have probably managed some good pics. Next time im down there,i'll take the camera!


I knew Id done one a while back,here's a pic.
[img][img]http://i596.photobucket.com/albums/tt50/lindarobjones/project%20stuff/Picture029-1.jpg[/img][/img]

[dixiethedog]

I was trawling thru my photobucket account and came across more pics of the zed with the gsxr motor in it.
But look away if your easily offended!
On a whim,armed with some tube and a tube bender,i decided to wrap some tubes around the engine,to make it a stressed member,and so to allow me to remove the frame cradle. I dread to say to make it a bit like a spondon or harris....
[img][img]http://i596.photobucket.com/albums/tt50/lindarobjones/project%20stuff/Picture008-4.jpg[/img]
[/img]

I then realised Id lost the V5 so abandoned it. Phew....take my tools away please...