Loss of Speed in top gear

Joined
Aug 27, 2003
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#1
My 1992 KDX 125 loses speed and appears flat in 5th and 6th gear, does anyone have an idea what the problem may be? I am considering taking the head off and pehaps decoking and new piston rings. Took it off road today around Leicestershire where I live and it performed well. On the roads it handles well but top speed is only 60mph and like I say 5th and 6th appears very flat.
 
Joined
Oct 14, 1999
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#2
Beside the more complicated (expensive) issues of a worn-out top end, a simple jetting error can lose the top 1/4 throttle....make the bike flat as a pancake!
 
Joined
Nov 14, 2001
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#3
Yeh, a top end would help, don't forget about those powervalves.
 

tedkxkdx

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Joined
Feb 6, 2003
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#4
Remember this is only a kdx125 not akdx200 off road version like many of the guys in the states have. If you are heavy than expect no more. If you are light it could be other issues like CC has stated. If you become a subscriber you can come over to my track and have a go on it. We could take a look at your issue too. Subscribe and then Private message me. I live very close to you.