You need to check the RC Valves are opening and closing correctly. I don't know how else to put it.
All the models have different length actuator cables, different sized valve flaps, and a different RC Valve control circuit/parameters. So you need to measure it all to ensure the sweep is correct. If the valves don't start and stop in the correct positions, at best it will affect power output, but at worst it could strain the servo motor and blow the PGM. Some combinations can be made to work, but some don't work at all.
We've see an MC16 with R5K barrels, heads, carbs, and expansion chambers struggle to make 50hp, and seen one done well that made almost 60hp. It's not as simple as just bolting bits on, even though technically they're [almost] all physically interchangeable. Not trying to pour salt on the wound, but we've even seen an MC18 with a mishmash of '88 and '89 bits that wasn't operating the RC Valves correctly and dropping 5-6hp.
It's the same with the HRC RS250R NF5. It's very easy to bugger one up by using the "wrong" year part that looks for all intents and purposes virtually identical to the correct item.
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Andy.
NSR-WORLD.COM
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