I've a question for which I can't find a definitive answer anywhere...… maybe there is someone out there who can help....
I bought a 1987 ZG1300 DFI in Switzerland last year and brought it back to Scotland, there were a few little issues with it which I've put right, and it's running quite well now.
But- being a Swiss bike, it's stated that the power is 58kW (77BHP). Now, I've nothing really to compare it to, and all I can say is it is smooth but maybe not quite as fast as I expected.
The burning question is, how did Kawasaki Switzerland restrict these bikes? I have been through the part numbers for both the Swiss and UK models for that year, and I can't find any differences whatsoever- cams, inlet rubbers, air filter, CDI, throttle bodies, injectors, all the same.
Does anyone really know? I can't even get an answer from Kawasaki UK !!
Are the mufflers & the rest of the exhaust system the same part numbers? I wonder if they restricted the power that way? I say that because the first bike I had on the road back in the early 80s was a Honda CB50J & they restricted the power on that by running a 1/2" pipe inside the header all the way from the cylinder head right down into the muffler. They also did it with the 2-stroke 125cc bikes (although that was just a washer welded in at the top of the header) to comply with the UK learner law. I wonder if on the Swiss Z1300 they ran a smaller diameter internal pipe on the headers (they're double skinned as you all know) or maybe the muffler internals are different?
Yes, you are right, the Swiss Z1300 had been restricted, I've heard about an even higher number, however I guess that does not matter. As what I know that had been achieved by limiting the throttle mechanically. The same applied for the 100 HP limit in Germany.
Did you look if there is a limiter that prevents the throttle from being fully opened ?
All the best, sitting in Switzerland right at the moment.
Z1300 A1/ KZT30AG built 1979
frame KZT30A 004285
engine KZT30A 000288
location: borderland-triangle France/ Germany/ Switzerland, Europe
I'm more aware of the use of restrictor plates between the carbs and intake manifold(s) to limit the induction of fuel/air in to the engine. There's lots of info if you goggle "racing restrictor plates".
Although restricting the exhaust will also limit the engine output, doing so would be somewhat harmful to the engine by holding up exhaust gases in the cylinder head and around the exhaust valves. Limiting the exhaust would diminish the scavenging effect that happens at the end of the exhaust stroke and the beginning of the intake stroke.
My vote goes for looking for a restrictor plate at the intake manifold /carb mounting rubber flanges or some kind of mechanical stop on the carb linkage to restrict wide opening of the carbs.
It's interesting that by going to fuel injection, they managed to increase the output by 10 HP.
That's my 2 cents.
I would be interested in hearing what the real answer is to this.