The search is on...

[BHarvey]

for a GS500E, or F, to build up as my 100+ mpg play bike.

Plans are to convert it from dual carb to single, install clip-ons, install Avon RoadRider tires(they roll VERY well) and streamline it similar to the 'Spud'.

A different exhaust setup will be required to avoid it hanging out in the wind, but that part is easy.

The single carb should perform extremely efficient since that one carb feeding both cylinders will get a much better ( more constant) signal from the exhaust.
It's metering should be pretty easy to get right since the more constant signal will reduce reversion.

Looking forward to getting started.

[redyaris]

An other bike you might consider in your search; is the Kawasaki Ninja 400. It is a fuel injected twin, compresion ration of 11:1, and it is liquid cooled. You may be able to find one with body/fairing damage for a good price. the new Canadian Kawasaki price is $7000.-

[FXSTi]

We don't get the 400 Ninja in the States. They also stopped production on the 500 Ninja. Now you can either get a 250 or a 600 or bigger.

My wife has a 2007 500 Ninja which I took out for a ride last week. 112 miles @ 59.1 mpg riding conservatively but not slow. My speeds were between 50-60 mph most of the time with a few dashes to 70 (indicated, probably 67 actual).

I think if you plan to change the fuel delivery, you may as well go with fuel injection. With something like microsquirt you could play with the fuel maps to lean it out under light loads.

[alvaro84]

Originally Posted by FXSTi

We don't get the 400 Ninja in the States. They also stopped production on the 500 Ninja. Now you can either get a 250 or a 600 or bigger.

It's pretty much the same here, but at least you can buy a variety of new 250s now. When I was seeking for a bike a few years ago, they were missing too, leaving a HUGE gap between 125 and 600 (for example, Honda had just discontinued both the CBF250 and 500 a year before that).

There are (quite) a few used 400cc bikes for sale, but it's pretty hard to get parts for them.

[redyaris]

An other type of bike for the on going search; could be a 350 - 450 duel sport single cylinder. There only drawback is a high seat height, although there are lowering links available for the majority of them. I suspect that changes to the intake/carbs would be easyer and cheeper than a multi cylinder engine. I also suspect that a 400cc enduro could get very close to what a 250cc bike could get for FE mainly due to the fact that it can produce enough power/torque at a lower rpm...

[BHarvey]

The only reason for the GS500 over one of the 250's is the extra torque. The full faring is going to weigh a bit more so the torque will be useful.

Now if Kawasaki would just stuff the KLR650 engine in the Ninja 250 chassis...........

I'd buy one today!