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difference between 800 and 800ho

202 Views 1 Reply 2 Participants Last post by  skidoo'sbest
any one help me out and explain the differ between regular 800 and 800ho motors was it timing or domes, or was it just differ porting. thanks
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If you go to the DOO website and click on past year models you can find what they did to boost the HO. I believe it was mild porting, new reed cage design, and some other stuff.

here is some more info

Engines with the H.O. (High Output) designation are the ultimate performing Rotax engines. The 600 H.O. is the class leader, winning grass drags in both single- and multi-pipe classes and the 800 H.O. set highmarks never before seen. For 2004, the 800 H.O. is now available in select MX Z and GSX packages.

600 H.O. Features:

Bigger engine block
8-petal reed valve
Nicasil cylinders


10% power increase *
Improved reliability
Better heat dissipation

800 H.O. Features:

Twin reed valve
Optimized exhaust porting
Increased compression ratio [Summit only]


5% power increase* [MX Z and GSX]
7% power increase* [Summits]

*Compared to
Rotax Series III engine
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