GS550 carbs on GS650 head?

[Chuck78]

Well my wife is now looking at KZ1000's, a bit long and heavy for someone 5'2", but I figured I needed to step up the game a bit to make her GS550 exceptionally apoealing to ride. 740cc 10.25:1 Wiseco pistons, 650 head and cylinders, Megacycle .380" lift cams, and vm28 carbs. The vm26 would work quite well I'm sure.the intake ports are about 27.## mm inside diameter, but I believe it's best in performance terms to not let the air/fuel mixture expand too much, as that may lead to some of the fuel condensing on the port walls. Just a tidbit I read on here somewhere about performance engine carb sizing. It outlined drag race vs road race scenarios, talking about RS34 and/or vm33 carbs. I believe for road race applications, the poster said port diameter 1mm larger than carb venturi diameter is best. For drag racing, I believe the poster said larger, but I cannot recall exactly.

[tkent02]

Unless all I had to ride on was interstate highways, I would MUCH rather ride the 550/700 from what I've seen so far.

[Chuck78]

As compared to a kz1000? Yes, I'd agree! My 920cc GS750 is down to about 480lbs after a major diet but adding much wider (heavier) tires and dual disc front brakes. The 920cc with advanced cams is a BLAST to ride, plenty plenty fast enough acceleration even far above legal limits. It's still a bit hefty when pushing around the yard and on uneven surfaces, but riding, only the tightest of low speed turns does the weight seem noticeably heavy. Carefully revised rake and trail helps out substantially, but racing around the neighborhood on my buddy's CB200... helps put the middleweight gs750 in perspective.

If I had it to do over again, I think a GS650E engine and frame would have been my top pick for a project base. The kickstart 550 bottom is something else though that I desire, but the later 650E frame and the 550 kicker, 650 top, Wiseco custom batch 740cc GS650 pistons, megacycle .380" lift cams... GS1100E swingarm, wire spoke wheels. 3.50 or 4.00x18 rear DID or Excel alloy rim, 2.50x18 front... racetech fork mods or CBR600F4 forks in VMAX1200 triples. $500+ YSS rear shocks. Pirelli Sport Demon or Bridgestone Battlax BT45V tires...