Oh all right then, I'll wade in.
I've retrieved a PM I sent insane1 when he was looking at one a couple of weeks back. Here's a harsh but detailed description of what can go wrong and what to look for in an RF900:
I've found mine to be pretty hard on front tyres - it tends to triangulate them, but its got a front-heavy bias so not unexpected.
The lack of a fuel gauge is a pain - especially with a reserve that lasts a good 80-90 kms.
Big problems with the carbs. Pay attention to the needle jets and the emulsion tubes they run in - its a problem with Mikuni downdraught carbies - friction as the jet needle slides and it wears the needles and emulsion tubes.
Big problem with the alternator cush drive - in some of the earlier models (94, 95) the drive for the alternator failed and they replaced a part to stop it snapping - unfortunately this part only lasts about 20,000 kms so needs to be checked often - and its a prick to get at too.
Don't leave it lying around in the rain because it won't run on four cylinders afterwards. It's a problem with the water either getting into the coils or the low-tension leads just behind the headstock. My solution is to smear Vaseline into the low tension connections as they exit the wiring loom and as they enter the coils. Others have had problems with the spark plug boots but not me, so I'm hesitant to say its an RF problem.
They run a 532 chain - so when you replace the chain replace the sprockets too and go with the 530 which was the GSXR1100 setup.
The brakes are non-standard for a Suzuki (Nissin - normally found on Hondas) but they will take the Tokicos from the Hayabusa which apparently is a mod worth doing.
The whole bottom end (with the exception of the clutch) is straight out of the GSXR1100 so its bulletproof.
The RF has a steel perimeter frame so in the unlikely event of a bent frame at least it is actually fixable, unlike an alloy frame.
Most RFs have about 125 at the crank, but you can get a lot, lot more. To meet American emission standards they did the same trick as on the gixxers - look for the pink wire just under the battery on the gear lever side - more midrange power in 3rd gear if you undo it. You can drill and remount the digital pickup as they will easily take another 4 or 5 degrees of advance. Also, putting in the cams from the 93 or 94 GSXR750 will help liberate even more power. With these two mods and a rejet you could get 160HP.
Good for 265km/hr on a good day. Best kept secret in motorcycling.
Don't let my harsh criticisms put you off. I love mine. I've done 32,000 kms on mine in 18 months. There is very little you can't do on one on the road, and I can keep up with all but the very fastest riders on one.
They're a sports bike the way sportsbikes used to be before they got all skinny and light. 
Oh - and as I tell every other RF rider - I have the Suzuki Factory repair manual and the fiche on my website. Let me know if you want the link to them.
And I to my motorcycle parked like the soul of the junkyard. Restored, a bicycle fleshed with power, and tore off. Up Highway 106 continually drunk on the wind in my mouth. Wringing the handlebar for speed, wild to be wreckage forever.
- James Dickey, Cherrylog Road.
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Originally Posted by xxxx
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