kz650b2A revs and redlines

Hi all,

My kz650b2a seems to be a bit obscure, I have found very little data on this bike, lots on B2 and B1 but not on B2A and after my experiences with the parts diagram, I know there are differences. here is the issue:

The Tach and Speedo are toast on this bike, I ride with a GPS and it keeps the speeding tickets away, but It seems to me that I am revving very high to sustain 90-100kms (60 mph) in my top gear. Other people have told me that there is a problem, that this bike should do at least a comfortable 100km/h does anyone know what the RPM redline equivalent would be in kmh/mph for each gear? If I had a clue about the RPMs while riding I would probably be more comfortable and not worry so much about over revving to run highway speeds. note for all purposes this bike is stock except the airbox is gone and K&N style filters are attached to carbs.....

Thanks for any and all!
Franco

Post edited by: franco, at: 2007/08/01 17:30

Franco,
KZ650's run at fairly high rpm, but without a tach you won't be able to do much more than guess. I took a look at Kawasaki.com and it shows part #25015-1011 as the tach for several KZ650 models including the B2A:

• KZ650-B1 (1977)-->METERS/IGNITION SWITCH
• KZ650-B2 (1978)-->METERS/IGNITION SWITCH
• KZ650-B2A (1978)-->METERS/IGNITION SWITCH
• KZ650-B3 (1979)-->METERS/IGNITION SWITCH
• KZ650-C1 Custom (1977)-->METERS/IGNITION SWITCH
• KZ650-C2 Custom (1978)-->METERS/IGNITION SWITCH
• KZ650-C3 Custom (1979)-->METERS/IGNITION SWITCH
• KZ650-F1 (1980)-->METERS

These tachs (and the matching speedometers) are often on eBay, in fact there are a couple nice ones on there now. I can't say how much$ they go for or if they're in your budget, but take a look at Kawasaki.com to see if the speedometer is shared by the B2A with the other models shown for the tach. You may be able to get them both for a good price. Good luck. Ed

On my 650C2 the engine is reving at about 5000~6000 rpm in 5th at 100 KPH. This is not very high, as the redline is up around 9000 rpm.

I switched to Kawasaki Synthetic Oil recently. I'm finding it has affected my rpms in a good way. The engine revs a lot freer and smoother. I used to cruise around 80 KPH in 4th gear most of the time before, but am finding now with the synthetic oil, I will often find myself in 3rd gear at 80 KPH.

When my 650 was new and had standard gearing it would run at 5600rpm at 120kph and somewhere around 200kph at 9000

check the gearing on the bike, someone may have changed it prior to you getting the bike

Mine with stock gearing (16/42) runs 60mph @ 5000rpm, 70mph @ 6000rpm.

i wanna know what the difference is from a b2- b2a?? anyone know??

fixer5000 wrote:

i wanna know what the difference is from a b2- b2a?? anyone know??

Gonna guess the "a" signifies model approved for sale in California (stricter emissions laws).

note for all purposes this bike is stock except the airbox is gone and K&N style filters are attached to carbs.....

I think you may want to think about re-jetting the carbs if you are running individual pod filters on the carbs. That is too much air for the stock jetting. This will effect how the bikes feels while riding at highway speeds.

On my 650C2 the engine is reving at about 5000~6000 rpm in 5th at 100 KPH.

Update, after a ride last night.

My bike actually revs at 4800 rpm at 100 KPH, in 5th gear. Normally I would not ride in 5th at this low an rpm, I'd be in 4th at 100 KPH, unless it's really flat land or I'm going down hill.

I've found the Kawi Sythetic Oil has changed my riding rpms. Much more power and freer reving than with the old recycled cheep oil I was using before.

OK Rob, nothing makes sense until I know what the heck 100kph is? Us Americans need that foolish "mph" stuff! Is there a basic formula for converting this? :blink:

OK never mind, I went outside and looked at the "little blue" numbers on my spedo. Do you guys have "little american numbers" on your spedos? So at 100kph I'm doing about 5300rpm's in 5th.