Q - Down on bottom-end power

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tmx
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Q - Down on bottom-end power

Post by tmx »

1998 KDX200
Exhaust: FMF Desert w/Turbine Core muffler
Reeds: Boyesen 607
Main: 152
Pilot: 42
Needle: Clip 2nd from top. I *think* it's a 1174.
Fuel: 93 octane premium w/Maxina Super M @ 42:1
Gearing: 12/47

I'm been having a problem with what feels like a lack of bottom end power, worse since installing the Boyesens a couple of weeks ago. By 'lack of bottom end', I mean from right off-idle to maybe a couple thousand RPMs there's no real snap, no pull. It doesn't bog, it just doesn't get up and go like it did before the swap, or like my last KDX200 (96) did before this one. The bulk of my riding/racing is in tight North Carolina woods, so off-idle performance needs to be there.

The jetting was set using plug readings and a bit of 'seat of the pants' testing, and is as spot-on as I can get it with a nice coffee-tan color at all throttle positions. I've alternated back and forth between a 40 and 42 pilot and settled on the 42 since it'll leave me with the adjustability range I'll need when things cool off again. Right now the air screw is at aprox 1.75 turns out. With the 40, it was just barely cracked open, maybe a quarter of a turn.

The KIPS works to the extent that I can actuate it via the nut under the slotted cover. I have not, however, checked its movement while running, nor have I pulled the exhaust yet to visually check that the valves themselves are operating. That'll be today's project.

On the positive side, the Boyesens made a huge improvement in the mid and top end power - peg the throttle and things get moving in a *very* big hurry. For that reason I'd hate to have to go back to stock reeds, but will if that's the only way out.

If anyone has any suggestions, I'd sure appreciate it.

Thanks,
-TMX
"Anything'll fly if you give it enough gas..."

VCHSS # 17s
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scheckaet
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Post by scheckaet »

did u mess with the nut on top of the kips actuator shaft? If so, have you supported the shaft? Might be a broken kips?
Did you insert the reed block correctly? I know some have an orientation...would explain lack of power
tmx
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Post by tmx »

Quick update (and thanks scheckaet for the response), it was the needle. Went from the second to the third groove and all is well.

Thanks,
-B
"Anything'll fly if you give it enough gas..."

VCHSS # 17s
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