Well I like my gs because its lightish and reliable . Disability means i just sold my fazer 600 because it was too heavy and i miss the power ... so wondering id anyone has fitted a nitrous kit to these reliable dobbins ... after a bit or a read it seems they can be used safely without damaging engines, another 15hp or so would really liven the suzuki ... thoughts please
Projects to make that much more power in a GS engine wind up breaking the crank. There's a racer who worked out getting a cut-down GSXR head with 2x as many valves onto a GS500 and was making power in the 60+ range, and in racetrack distances wound up going through cranks.
You want 70hp in a bike the size and weight of a GS500 then you need a SV650. Or more money, MT-07. You can probably sell the GS and put $500 with that and get an SV650 of similar age and condition. That's by far the best way to get more power in a similar chassis.
I'm 100% with mr72 on this one. These engines weren't designed for the pressure that comes with NOS and forced induction. It's hard on the crank, rings, rod bearings, and can make a lot of heat for the poor air cooled twin.
Get a larger twin to keep the weight down like the sv650 mentioned, or MT-07, ninja 650 etc
Another option: rather than worrying about increasing the power of the engine, why not choose to apply the power it already makes in a different way? Maybe try out a smaller front (or larger rear) sprocket? Maybe that will give the bike the feeling you want.
After reading futhur and listening here , I agree , nitrous is not a great idea .... and i want the highish cruising speed so re-gearing is not what i am looking for either ... Perhaps an sv650 is worth a trial ride and then wait until a cheap one comes along locally should it work .. thanks for your advices