Stock frame and swingarm mods

Anybody have any experience with stretching the downtubes on KZ650/750 fours? I did the mods and am assembling the bike. I also stretched the swingarm and driveshaft 3 inches. The bike is an '82 KZ750N1 Spectre

www.ratpackcycles.com/skpage/Frankenchopper/frankenchopper1.htm

I designed the extensions and ensured that they're well-installed (engineer, y'see), but I'd like to get some thoughts from someone who's actually done these type mods.

Thanks in advance...

I've done similar work and followed the basic guidelines found in "The Custom Chopper Cookbook". Lots of chopper frame mod info. The book shows up on ebay now and then, I found a copy in a library a few years ago too.
It may a be little late to be asking for advice, looks like you're already done! Just hope you sleeved the joints a few inches with seamless tubing taper bored at the ends.
I like the stance and the way the lines flow -if you're gonna build a chopper, build a proper 70s style raked/stretched/lowered chopper!

Post edited by: Fossil, at: 2007/05/29 14:25

You're right - the mods are done, and I can't wait to get the bike on the road. I was looking for someone who has done these and then actually had the bike on the road, for opinions as to driveability/comfort/safety.

The downtubes were cut horizontally and I drilled the tubes an inch above and below the cut for later plug welding. The 3.3-inch downtube extensions were made from downtubes from another KZ750 frame I have. They were installed with sleeves which were welded through the holes previously drilled. The whole stretch was done on a jig to ensure that the steering didn't move left or right. Ought to be plenty strong.