is it time for a new top end?

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bws2
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is it time for a new top end?

Post by bws2 »

I have a 2001 KDX 200 that I bought back in Feb 2014 from the original owner, who told me he'd never redone the top end.

The bike appeared to be in good shape and the owner said he had mainly ridden it with his kids, just putting
around, with an occasional longer ride with his friends. He estimated about 400 miles total.

In the time I've had the bike, I ridden it about 10 hours.

Compression check is 150 psi, but I've been having lots of spooge, and recently the bike dies on the trail, but comes back to life after a spark plug change (old plugs are black and wet).

I'm new to bike maintenance, so I don't know when a new top end if needed.

Can you guys help me?
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Sullyfam
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Re: is it time for a new top end?

Post by Sullyfam »

It never hurts to pull the head off a new to you bike regardless of what the seller tells you. 150psi isn't bad at all, but the spooge to some extent is normal.

That said, in your case with the bike dying and black wet plugs I'd say you have a jetting issues to deal with first. Your bike is running rich (common in stock form). Check out the How to Jet your bike steps on the this forum and you'll be golden. Then take a peek at the top end. Also, if you haven't already put on an hour meter. Makes life much easier and IMO worth the $20-30.


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bws2
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Re: is it time for a new top end?

Post by bws2 »

Sullyfam wrote:It never hurts to pull the head off a new to you bike regardless of what the seller tells you. 150psi isn't bad at all, but the spooge to some extent is normal.

That said, in your case with the bike dying and black wet plugs I'd say you have a jetting issues to deal with first. Your bike is running rich (common in stock form). Check out the How to Jet your bike steps on the this forum and you'll be golden. Then take a peek at the top end. Also, if you haven't already put on an hour meter. Makes life much easier and IMO worth the $20-30.
Thanks Sullyfam. I had been reading about jetting and saw where the bike needs to be good mechanical order, otherwise it'll be impossible to get it jetted correctly. That's when I started thinking about the top end.
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Re: is it time for a new top end?

Post by ohgood »

top end ? bah !

I put 278 miles on mine in the last two weekends, yours just needs the jetting tuned up and the pipe blown out with some throttle action :-)
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Sullyfam
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Re: is it time for a new top end?

Post by Sullyfam »

True your bike needs to be in good working order to properly sort out jetting Issues, but your compression seems fine and you symptoms indicate the jetting is the issue.

After 13yrs I'm sure the top end could use some attention, but I wouldn't get too concerned until I got the jetting fixed.


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KDXrider1989
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Re: is it time for a new top end?

Post by KDXrider1989 »

my '89 probably hasn't had the top end rebuilt in over 10 years (if it ever has) and probably has around 70-80 hrs on it, still cranks around 175psi hot last time I checked and has plenty of power. If good premix was always used at 32:1 OR 40:1 and didn't beat the hell out of it you should be good

on a side note I should consider rebuilding my motor real soon :toimonster:
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Re: is it time for a new top end?

Post by Bitteeinit »

I think the bigger question is why would an 89 have so few hours on it? Is it used as a piece of furniture or something?

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Sullyfam
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Re: is it time for a new top end?

Post by Sullyfam »

Bitteeinit wrote:I think the bigger question is why would an 89 have so few hours on it? Is it used as a piece of furniture or something?

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Agree, 10yrs and less than 100hrs?!!!

Still, at about 70hrs it's not a bad idea to think about a top end IMO. May not be for everyone, but I've never had a bike seize on me not experienced a DNF in +35yrs to riding/racing. Yeah me. [emoji51]


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KDXrider1989
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Re: is it time for a new top end?

Post by KDXrider1989 »

who knows, it very well could have 100 or more hours :shock: I know it sat up for a while when I got it which gives me reason to believe theres a possibility the motor has never been apart. Still starts first kick every time and has good power, but yeah a rebuild is in need very soon, I know the transmission needs some attention
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Sullyfam
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Re: is it time for a new top end?

Post by Sullyfam »

Sounds like a top and bottom end - Let the rebuild thread begin!


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