900/1000 dogs compared to 650/750?

I went to an old bike dealership here in Tennessee and talked to two old bike techs that are semi retired. I went in to show them my alternator(650c1) and ask them how to wire it. We got to talking about my KZ1000B3 I rode in on. They said the 900/1000s were dogs compared to the 650/750s. I will agree my 650 is as fast as my 1000 but the 1000 has a full fairing and bags and trunk. TJ the younger one(about 45-50) said his 750 was faster than the drag bike the other tech had built and the second man agreed. I was going to build my 650 as a cafe racer but might drop the idea of mildly tuning it. They said it was cheaper to build a screaming 810 than to mess with welding the crank and such in a 900/1000. Any one have info on dollars per horse power?

tell them boys to come up through louisville ne in the springtime,ill blow the dust off my ltd/z1 clone and we'll find out! :woohoo:

where in Tenn is this ? in the mountains on curvys he may be right, I had a state trooper tell me once that any decent 650 (this was back in the day) could lose a state patrol car on mountain roads (an experienced rider of course), on straight roads however if they're both the same vintage I have a hard time with that statement, ole TJ needs to start wearing a respirator around those "chemicals" :woohoo:

A good running 650 is a bike not to be under estimated but against a 1000, not a chance! This guys on crack! lol

actually crank would be a better guess, shit does make one delusional

Actually, the 650/750 thing is a common myth that still persists. When I purchased my 1982 GPz750 back in 2001, the owner told me what a hot bike this bone-stock 750 was. It was, according to him, much faster than the contemporary 1982 GPz1100. I smiled and handed him the money. Never argue with people like that.

I think some of this comes form the fact that most people will ride a smaller bike harder than a large bike because bigger bike scare them. I know I ride my 83 650 nighthawk much faster and more agressively than I ride my KZ1000. I can redline the 650 in every gear, but I feel if I ride my KZ like that I'll be a ball of red meat in a ditch somewhere. also smaller engines can rev higher, my friend had a little honda CB1 400 sportbike, that thing was fast but its hard not to be quick when you can turn 14,000RPM! everybody thinks their bike is the fastest especially the harley guys. I don't understand why they think 1940's 2 cylinder airplane technology is so fast and superior to modern 4 cylinder bikes but to each his own. But anyway kz650 faster than a KZ1000, no way.

It's an old racing adage from way back,
Still true in the metric world, There is no substitute for Cubic Centimeters;)

I beat a Volkswagon Beetle with my 750 twin, ran away and left him!!

ezrider714 wrote:

It's an old racing adage from way back,
Still true in the metric world, There is no substitute for Cubic Centimeters;)

...there is no replacement for displacement...

I'll comment on the dollar front. I spent around three grand to build my 810 engine. Can't see hot rodding a 1000 to be any different.

Ok went to get some parts and asked about the bikes in question. The 750 is a GPZ with an 810 kit. Ported heads, crane cams, dyna plate, header and 34 cv carbs. The guy lives above cleveland tennessee so goes to dragons tail in North Carolina about once a month to play. The 1000 has a set of denco pistons and is about 1175cc. Worked head, header, denco cams, air shifter, longer swing arm, drag bars. It was fuel injected at one point but has carbs now. They both still say that the plain bearing engines are cheaper to build and stronger than the roller bearing engines. Both say you NEED to weld the crank to safely increase the performance of all the roller motor engines and that is just wasted money on a street(track day every 3months) engine when you can spend the money on a plain bearing engine and make more power in a streetable package. Also the transmissions on the 900/1000s had transmission problems like 2nd gear, that the 650/750s did not.

I dont think you can really spin the plain valve engines any higher to make up for the smaller displacement. I think the engines will run into valve train characteristic speed limitations before piston speed.


The point they were getting at was not to cafe the 1000J I have in pieces, instead build the 650 with the 750 block I got from them and but an 810 kit in it. The bike will be much faster around the track than a 1000 on a dollar per dollar bases. Also it will be less likely to break.