Sparkplugs The factory manual recommends Champion RA4HC with a 0.6mm electrode gap. For the 900ss, the manual recommends Champion RA6HC (0.6mm), two ranges colder. I always found NGK to be the superior plugs. Converting Champion RA4HC to NGK gets DCPR8E with a 0.9mm electrode gap. Converting Champion RA6HC to NGK gets DCPR8E with a 0.9mm electrode gap. So Champion says two ranges colder for the 900ss, but NGK says identical heat ranges. Looking up NGK for plugs suiting the 600ss NGK recommends the DPR9EA9. One range colder again. I found the DPR9EA9 fouled, so I recommend one range hotter DPR8EA9. A platinum plug DPR8EVX9 would be best, but DPR8EA9 are $3.50ea (Aus) and platinum’s are $20.00ea (Aus) Dynojet kit: E7104 or RF7104 ($200? Aus) Same as M600 K&N airfilter: DU-0900 ($100? Aus) Same as M600 Octane rating The octane rating (RON) is not a measure of the power available from fuel, but how well the fuel resists detonation, pinking, pre-ignition, knock, call it what you will. Adjustable fuel injections systems can take advantage of premium fuels which are denser and have a higher RON by advancing the timing, getting more power and economy, but carbureted engines (600ss) may simply run too rich and foul their plugs. Switching back to standard fuel or re-jetting will fix this problem. Unleaded fuel has a RON of 91. Shell Optimax, Mobil XXX and BP ultimate all have a RON of 98 A Staintune muffler (PART # DUCMS6SS2-1) looks great, but can have a slightly annoying resonance in them. Carbon mufflers have a much mellower sound, but are more expensive and don’t look as good. Modify the side stand self-retracting mechanism by cutting off the head of the Allen screw that holds the spring. The difficulty in finding neutral can be cured by fitting a braided hose between the clutch lever and slave cylinder (this opens the clutch fully and avoids drag). This hose carries less volume than the stock one making the lever throw more efficient.