Labratmike
Member
- Dec 17, 2005
- 5
- 0
I've got a KDX220 and love it. Just came 61st (out of 350) in a dirt bike rally in Wales - on open terrain against much bigger bikes so it goes well enough. Mine has uprated reeds / reed block, an FMF pipe and can and an opened up airbox. It's quick and quite peaky, with a big step in power high up in the rev range. But it feels very flat in the mid-range. It's so peaky that when changing from 5th to 6th you almost always drop out of the power, even when thrashing it on tarmac. I looked at the power valve actuating rod. If the rod is properly connected to the valve it's definitely not stuck open, but it appears to open fully as soon as the engine is picked up off tickover whereas I expected it to open progresively until high revs. As I bought the bike when it was five years old I don't know much about what might have been done to it by previous owners to tune it. Is it normal for the power valve to open so early? If the control rod moves fully does it follow that the exhaust valve itself is also opening? Is it adjustable in any way or do people change the strength of the return spring? Are there other likely culprits for the lack of mid-range in a bike that is known in the UK for it's tractability? Any advice welcome.
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