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Discussion Starter #1
hello everyone, new to this fourm and love it, friendly and healpful people and information
i purchased a 79 gs550e for 1,000 with 14,000 miles very fun, runs great would like to do more modfications this winter and one of tehe is performance ,
i have seen some disccution on this but most is just re jet stuff im looking for a little more, i have seen some talk of putting different heads and carbs on the 550 bottom end spifically th 650 katana, but knowng there are mny different years of katanas i was wondering if anyone recomends a specific year or model that bolt on , also are there other head/carb combo i could try? (looking for around 70-80 hp)
 

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Yeah, the 650 made 73 HP @ the CRANK. The 550 had 49 HP at the crank. (subtract about 20% for rear wheel HP) You are not going to get that much, just by swapping heads. There's a matter of an 18% increase in displacement. I am not sure what carbs would go with that kind of change, or if the 650 head would even fit. I do know that heads from a post 1980 550 won't work, because the carb spacing changed when they went to CV carbs...(which BTW are extremely difficult to tune without an air box). And I would assume you would need to modify or eliminate the air box with a carb change. And you would, at least need a rack to match the 650 head that you could install what ever carbs you went with.
 

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A 650e motor will probably bolt straight in (Suzuki was pretty good at keeping engine mounts the same). The 650e was a pretty rare beast over here (way more G's than E's), but appear to be much more plentiful in the US.

Or a 600 Bandit motor.
 

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Discussion Starter #5
haha thanks guys usfull information, im always torn between keeping it old school and using new parts, id love to swap in an entire 650 motor or even get crazy and get a gxr 600 but i always mourn for keeping the original motor and carbs haha
 
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