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2001 KX250 POWER?

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I had to sell my 05 WR 450 about 7 years ago (had twin boys). About a month ago I bought an 01 KX 250. I haven't rode since I sold my bike, and its been close to 20 years since I've rode a 2 stroke. I couldn't afford to go back to a four stroke. Well the problem I'm having is the bike just doesn't seem to have the power it should (see below for details of bike). My cousin has the same bike except its all stock. While we were riding last night we got on a flat section, we both cracked em, and he was basicly toying with me, I couldn't touch him. :( The 2 things that are most noticable are 1. When rapped out and you shift from 1st to 2nd you have to imediatley shift to 3rd because your already rapped out in 2nd as well.

2. Top end when I'm rapped out in 5th he is still walking away from me.

 

 

Bike set up.

2001 KX 250

Topend done within 10hrs

Pro Circuit Platinum pipe

FMF Shorty Silencer

VForce 3 reeds

Port and Polished by LA Sleeve

14/49 sprockets

 

Any comments or concerns are greatly appreciated. It just seems I should have more power than I do, or is this what I get with this setup?

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I can't address most of what you're asking but be aware that 1st and 2nd gears are practically the same ratio. I generally don't use 1st at all. Lots of folks move to 1st gear out of an older kx.

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From what I can tell it seems to be working, you can feel a difference. I haven't tore into anything yet, was hoping to get through till winter and tear it all done.

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I can't address most of what you're asking but be aware that 1st and 2nd gears are practically the same ratio. I generally don't use 1st at all. Lots of folks move to 1st gear out of an older kx.

When I hop on my cousins you seem to have a full range through all gears. Could the previous owner changed gears? But if so why would you put them so close???

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When I hop on my cousins you seem to have a full range through all gears. Could the previous owner changed gears? But if so why would you put them so close???

I have an 01 also. Not much difference between 1st and 2nd. For some reason they came with a tall 1st.

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99-01 have a very high first gear, don't know why. I put 94-08 first gears in mine or a KDX 250 transmission but I never leave a 99-01 first gear in them.

Ed

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99-01 have a very high first gear, don't know why. I put 94-08 first gears in mine or a KDX 250 transmission but I never leave a 99-01 first gear in them.

Ed

Do you just buy the gear new?

I'm going to swap mine when I have a reason to tear it down

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Are you sure your clutch isn't slipping?

I asked the same question of someone I know w/99 KX. Said his clutch was good. I took it for a ride...wrong, slipping. It started slipping at about 2/3 to 3/4 throttle under hard acceleration.

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Do you just buy the gear new?

I'm going to swap mine when I have a reason to tear it down

OK a small edit, it is a 94-98 first gear. I have bought new parts but most have been Ebay parts. New is kina spendy cuz you need the input shaft and the matching gear and the shaft is over $100, don't remember what is cost but the shaft and gear new were over $200 and I have bought Ebay transmissions for $20 before.

 

Ed

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I asked the same question of someone I know w/99 KX. Said his clutch was good. I took it for a ride...wrong, slipping. It started slipping at about 2/3 to 3/4 throttle under hard acceleration.

Well I don't feel any slippage it feels good all through the RPM range. Is there something in particular to look or feel for, maybe I'm missing something. Thanks for the responses so far all, now I remember why I was on here everyday in years past. :thumbsup:

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Well I don't feel any slippage it feels good all through the RPM range. Is there something in particular to look or feel for, maybe I'm missing something. Thanks for the responses so far all, now I remember why I was on here everyday in years past. :thumbsup:

My friend's 99 wasn't obvious to him, or me...untill I checked for it. It was really noticeable upon hard(pin it to win it) throttle. It wasn't obvious during part throttle use. It felt good revving out...just not delivering power through to the wheel.

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I bet the PV components are shot. You need to go farther than the visual check of the actuator moving.

The top end won't be there without the PV working properly.

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Well gonna take it to a buddies tomorrow night and take off the side cover and see if we can see anything noticeable, if not Prolly gonna have to tear into it deeper...:(

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Powervalve is a possibility, but to check the clutch find a good steep hill, paved is best, get it in high gear and start playing with the throttle.

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Clarify this a little for me is it the top end power you're lacking or top end speed?

 

Have you checked to see if the last owner has a higher tooth count on the rear sprocket? Go check the tooth count it should be marked some on the sprocket.

 

Also is this "10 hour" on the top end, is it a top end you installed or is it what the PO has told you? If its the later it's a lie, 99% of the time. Every bike being sold has ten hours on the top end. My bet is you may need a top end rebuild. Fist thing would be to check compression.

Edited by moose_338

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Clarify this a little for me is it the top end power you're lacking or top end speed?

 

Have you checked to see if the last owner has a higher tooth count on the rear sprocket? Go check the tooth count it should be marked some on the sprocket.

 

Also is this "10 hour" on the top end, is it a top end you installed or is it what the PO has told you? If its the later it's a lie, 99% of the time. Every bike being sold has ten hours on the top end. My bet is you may need a top end rebuild. Fist thing would be to check compression.

14 front 49 rear on the sprockets

it just doesn't seem to have the power it should, my cousins stock 01 KX 250 is faster through all gears, but really noticeable on top

Thats what the PO had told me

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Ok well last night me and a buddy checked the PV arm was functioning properly, cover off started bike checked while running, pulled the exhaust and checked to make sure they were opening, while we had the exhaust off noticed some light scoring on the sleeve, so think I'm gonna have to tear it down and do the top end.  I should know by now not to trust what someone tells me. Also took the carb off checked the reeds and checked jets. The main jet was a 165 and the pilot was 50. With the VForce3 Reeds do you need to do anything with the jets? Or is that more of a Boyesen thing? Thanks again all appreciate all the great responses.

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