TOPIC:

Before you do anything, adjust the clutch at the sprocket cover. Sounds like it isn't disengaging at startup.
Steve

I must say that it's mostly not the bike at fault here, but the rider

I could not get the clutch to slip.

Mostly I've been riding in town with traffic, so it's been hard to get good numbers.
Today I took it out of town with another rider on a KLR. It was the first time that I had it on the open road. We were averaging 110km/h with my KZ running at around 7500rpm. At one stage I was going at a speed of about 130km/h at about 8300rpm (this is harder to verify as we weren't together at this stage)

It was an 80km round trip and not once did the clutch slip, and even at 8000rpm there was still throttle left.

According to Gearingcommander.com I should be doing 110km/h at 5500rpm with the current setup, but I don't expect the motor to run like it did at day one.

Any advice on sprocket sizes I should be looking at for a more comfortable cruising RPM? At which gear ratio would one start bogging the engine?

Get the stock size sprockets.
Steve

Contact Z1 and ask em what 530 set up is equal to the stock 13/32 630 set up. Be sure to tell em about the 16 inch tire too.

A 16 tooth front would get you at 2.5 cheap and easy then go to a 38 or 39 if you want a little more.

16" tire will lower the gearing a lot.
Steve

The chain size (530/630) does not effect the gear ratio. It is the spacing of the pins and width of the chain. Stock ratio for you bike is 2.46. Going to a 37T rear would be identical. However, with your 16" rear wheel, you may want to consider a 36T rear. This would be slightly taller than stock (2.4), correcting for the smaller diameter wheel.

KZB2 650 wrote: Contact Z1 and ask em what 530 set up is equal to the stock 13/32 630 set up. Be sure to tell em about the 16 inch tire too.

A 16 tooth front would get you at 2.5 cheap and easy then go to a 38 or 39 if you want a little more.

I'm from South Africa so I'll check whether I can source anything local first. The local Kaw dealer hardly responds to my emails though, they don't care much about old bikes.

MDZ1rider wrote: he chain size (530/630) does not effect the gear ratio. It is the spacing of the pins and width of the chain. Stock ratio for you bike is 2.46. Going to a 37T rear would be identical. However, with your 16" rear wheel, you may want to consider a 36T rear. This would be slightly taller than stock (2.4), correcting for the smaller diameter wheel.

Huh. What size tires are you guys running? The rim has to be stock, do I just have a smaller tire?

I'll replace whatever I can depending on which parts are available. I'd really like to get the revs down, hoping it'll save some fuel too.

Take a look at the link below. It contains a tire size calculator that can be used to determine and compare the diameter and circumference of different size tires, and it shows what the speedometer difference between the two tires will be. The metric rear tire size typically used on the KZ650-B and KZ650-C models is 120/90-18. If you compare the size of the tire currently on your bike to that typical size you will be able to see the differences between the tires. Ed

www.tacomaworld.com/tirecalc?tires=130-90r16-120-90r18

This is crazy...... a 16t front and a 39 rear is gonna get you right at (or a little lower 2.43) than the stock 2.46 final ratio (15f/37 rear right at 2.46) which is stock (according to MDZ1 rider) but I really don't think its gonna lower your rpm from 7,500 to 5,500 at 68mph (110 km/h). Maybe only 6 or 700 ??? I can't find the final drive ratio on the net but I assume that 2.46 already has the 16 inch (LTD) tire figured in which is only 11/4 inch smaller in dia than a standard model 18 inch...... What the hell are we figuring wrong guys......... One more thing have you counted shifts maybe 5th is out.

650ed wrote: Take a look at the link below. It contains a tire size calculator that can be used to determine and compare the diameter and circumference of different size tires, and it shows what the speedometer difference between the two tires will be. The metric rear tire size typically used on the KZ650-B and KZ650-C models is 120/90-18. If you compare the size of the tire currently on your bike to that typical size you will be able to see the differences between the tires. Ed

www.tacomaworld.com/tirecalc?tires=130-90r16-120-90r18

Thank you, that is quite a handy page. I must mention that gearingcommander does take tire size into account though.

KZB2 650 wrote: This is crazy...... a 16t front and a 39 rear is gonna get you right at (or a little lower 2.43) than the stock 2.46 final ratio (15f/37 rear right at 2.46) which is stock (according to MDZ1 rider) but I really don't think its gonna lower your rpm from 7,500 to 5,500 at 68mph (110 km/h). Maybe only 6 or 700 ??? I can't find the final drive ratio on the net but I assume that 2.46 already has the 16 inch (LTD) tire figured in which is only 11/4 inch smaller in dia than a standard model 18 inch...... What the hell are we figuring wrong guys......... One more thing have you counted shifts maybe 5th is out.

It does shift into 5th. Does anyone know what I'd need to change regarding the tire/sprockets to drop about 2k rpm on the top end? It's difficult using the online tools, as they account for a factory, ie brand new engine.

Do a search using kz750 ltd or kz750 ltd gearing maybe a few other ways and you'll find more info on here that's pretty close to what were stating. "I did the 630 to 530 conversion on my ltd" has alot of info...... maybe a 17 tooth front sprocket along with your 40 rear? Or start with a 16 to see what it does? Things still are not right with your 7,500 at 68mph though according to the search and gear commander.

Though it sounds like the clutch doesn't slip I'll just add that even with correct oil made for wet clutch you can still get problems. My old bike couldn't pull hard on Shells top oil (rotella? Can't remember the name) but ran fine with everything else I tried.