I need more top end!!!

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masterblaster
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I need more top end!!!

Post by masterblaster »

Hi this is my first post and I'm not proficient with the search engine so forgive me if there are several threads on this already but....I just got a near mint almost stock (except for a fmf fatty &isde silencer/jetting to match) 97 kdx200 and I am in love, as a former mx guy I cant believe how well this does in the tight single track behind my house. I am very happy with the power except for the over rev I have the carb dialed and she runs very strong through the mid and seems to fall off shortly after. I rode my brothers kdx and it seems to be the nature of the beast...so my very long winded questions be; how can I get more top end without losing too much bottom? I have done several light porting jobs on 125's any pointers for the 200? will a larger front sprocket help the gears pull longer? were can I find usd forks that don't cost as much as the frickin bike?
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KDXGarage
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Re: I need more top end!!!

Post by KDXGarage »

Welcome to the forums.
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
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G22inSC
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Re: I need more top end!!!

Post by G22inSC »

Make sure you have the "Rev" pipe and not the "Woods" pipe.
'05 Kaw KDX200 ('00 KX125 forks / '02 RM125 Showa "K2" shock)
'14 Yam YZ125(x) (oldest boy's)
'22 Yam YZ125X (youngest boy's)
'17 Yam YZ85 (soon to be FOR SALE)
'10 Honda Recon (wife's)
'08 Kaw KX65 (Sold)
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'09 Yam PW50 (retired)
'97 Kaw KX250 (Sold)

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ArkAngel
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Re: I need more top end!!!

Post by ArkAngel »

Welcome
KDX 200
KDX 250
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adam728
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Re: I need more top end!!!

Post by adam728 »

Since you've been in the carburetor, what size is it? Going from your other post about it being sold as a 220, I'm thinking it could have been, then had a cylinder damaged and the owner picked up 200 parts. The 220 carb is 33mm and known to be a restriction on top end. The 200 gets a 35mm. Either can be reworked by RB Designs and help top end.

Just a thought. Also as said, make sure its a rev pipe and not a woods pipe, big difference in top end.

After that, then worry about internals (porting, head mods).
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Jaguar
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Re: I need more top end!!!

Post by Jaguar »

put an adjustable CDI on it and adjust it for best top end power
Performance CDI -- KDX motocross mods -- the SR KDX -- expansion chamber analysis---> http://www.dragonfly75.com/moto/
bossmans kid
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Re: I need more top end!!!

Post by bossmans kid »

I'm no KDX expert but I'm curious if you have a bad reed pedal. A tiny crack or air leak on the edge can cause poor top end performance. Just a thought.
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adam728
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Re: I need more top end!!!

Post by adam728 »

bossmans kid wrote:I'm no KDX expert but I'm curious if you have a bad reed pedal. A tiny crack or air leak on the edge can cause poor top end performance. Just a thought.
Bad reeds have a MUCH bigger effect at low speeds. The reeds below were thanks to me forgetting to tighten the screws on the top pedal. As the day went on the bike lost all bottom and and became a bear to start. Get the revs way up and it felt like nothing was wrong. I've seen small engines eat a reed and run like nothing is wrong at high revs.

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masterblaster
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I need more top end!!!

Post by masterblaster »

After some research I've decided to go up a tooth on the front sprocket add a wolfpack cdi and get the rb carb mod before I touch the porting and see if I that satisfies my 125 topend induced mania thanks all for the replies I will post my results in 3 weeks
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