Worlds Biggest KZ650?

Hey gang - Here's speaking from my experience last season with my 29 year old Kz middleweight.

I have owned over a dozen bikes and educated myself on how to get the most out of a motor through trial and error on MX'ers and dirt bikes. In my opinion, these are the best toys to learn how to properly drive a motorbike.

On my 650 (with the factory Kz650 badges ) with the Wiseco 810/750 cams, Gpz 750 intake valves, WG Mikuni 28 carbs, Dyna stuff and pipe, I easily outran my buddy's (1991?) Katana 600 off the lights. It wasn't even close. On a roll at 70 mph, I pulled away at will, and this was with a 14 tooth drive sprocket, which is even better outta the hole than on a roll.

I also ran with a 1984 Kz750 with a pipe and filters on the highway and pulled away from him without breaking a sweat when we both dropped a gear and lit 'em up. He shifted sooner than I did and that little extra stretch of (10,000 plus) rpm I held onto left him behind. This 810 with the 750 upper end really loves the high revs.

I even showed an old GS1000 (original owner) what my little hot rod could do when I launched around 4 grand from a deserted stoplight late one night. When he caught me at the next light he just grinned. I don't think he was used to hammerin' his GS so hard off the line and was in all honesty probably not shifting at redline, but he was still pretty shocked at the power of my 650 badged ride. The guy told me that he knew these 650's were quick for their size but he didn't think they were THAT strong! I didn't tell him about my hidden upgrades.

Lastly, I had a little joust with a GSX750R one evening. He pulled up beside me at a light when I admired his shiney new ride. He told me he just picked the bike up and it was his first street bike.

When the light changed the guy pulled up beside me and was riding the back wheel around 30 mph. I didn't want to run him over in case he lost his balance so I pulled slightly ahead of him dropped a gear and pinned it. He finally blew by me around 80 mph. When I hooked up with him later on he said that he was still learning the bike's powerband and was gaining on me when I rolled off the throttle. Now I fully realise that my old bike couldn't run with current 750 technology in a head-to-head squirt, but sometimes you can catch these inexperienced and cocky guys napping:)

In short, I would advise, don't judge a book by its cover. The big Kawasakis the 900/1000/1100's are expected to be fast, but the little 650's can slip under the radar. The same can probably be said of the little old RD350/400 Yamaha 2 strokers that could surprise bigger bikes up to 40 mph.

In short, give me a bike that I am comfortable on and know how to drive. One that I have confidence won't blow up on me at high rpm when I am tucked in tight and shifting without the clutch. Let me get the thing into its power band quickly and I will show you what a little middleweight in the hands of a reasonably expererienced middle-ager can do....and don't always believe what the side covers say.

Cheers-Colin Firth-Ontario Canada

Post edited by: reborn650, at: 2006/12/11 21:34

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Post edited by: wireman, at: 2006/12/14 08:46

I still have my 904 engine and plan to install it in my streetbike over the winter. The block was originally made for someone else with a KZ650, but the purchaser never collected it from the manufacturer so I picked it up cheap (relatively), installed 1100 sleeves and bought 73mm forged pistons to suit. My alky motor was last run as a 760cc using a 738 block resleeved (thicker) and bored 1mm bigger using RC Eng turbo pistons originally destined for a CBX1000 Honda. In that format it ran 8.69 @ 162mph. It has big alloy rods, a re-cut speeded-up gearbox and lots of other goodies. I'm going to keep my current turbo system but add a Dynapro V500 ECU and 3 stages of nitrous using 2 solenoids. Here's the block. It's main purpose is to allow large capacity while adding support for the sleeves and also support the crankcases to help prevent them flexing under high loads.







Post edited by: Lorcan, at: 2006/12/14 04:40

Lorcan wrote:

I still have my 904 engine and plan to install it in my streetbike over the winter. The block was originally made for someone else with a KZ650, but the purchaser never collected it from the manufacturer so I picked it up cheap (relatively), installed 1100 sleeves and bought 73mm forged pistons to suit. My alky motor was last run as a 760cc using a 738 block resleeved (thicker) and bored 1mm bigger using RC Eng turbo pistons originally destined for a CBX1000 Honda. In that format it ran 8.69 @ 162mph. It has big alloy rods, a re-cut speeded-up gearbox and lots of other goodies. I'm going to keep my current turbo system but add a Dynapro V500 ECU and 3 stages of nitrous using 2 solenoids. Here's the block. It's main purpose is to allow large capacity while adding support for the sleeves and also support the crankcases to help prevent them flexing under high loads.

<br><br>Post edited by: Lorcan, at: 2006/12/12 13:44

now i are scured!:blink: :evil:

Thanks for posting this Lorcan and I will really be looking foward to the updates on this!

Back in the late 70s, 80s I worked in a machine shop for 11 years and got vg on a bridgeport. Seriously thought about making something like this more than a few times but the cash kept me from it.

I would have been lucky anyway to handle the power of a mild 810 let alone anything like this.:laugh:

I missed this the first time around.
Any updates Lorcan?