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Just put a fresh top end on a 03 ktm 125sx and it doesn't seem to pull hard until your 3 quarters of the way through first gear, but even then it doesn't seem that it's pulling as hard as it should. Could this be carburetor issues or maybe power valve issues?

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It's a buddies and he bought it with it needing a top end. I'm thinking the carb is completely stock because the rest of the bike is. It could possibly be the power valves. Any suggestions on tuning them?

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Have a look at when the power valve opens - the inspection window on the left hand side of the cylinder will show you where it is set. There is a lot of info on the internet about how to adjust the system for an early or later 'hit'.

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Have a look at when the power valve opens - the inspection window on the left hand side of the cylinder will show you where it is set. There is a lot of info on the internet about how to adjust the system for an early or later 'hit'.

Alright. Thanks for the response bud I appreciate it! I'm used to working on hondas and kawasaki this is the first ktm lol

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Well I got it adjusted and put back on, come to find out it was missing 3 of the little collars inside the pv cover. When I said fixed I meant I figured out why it was lacking power, I got the power back for a hole 4 seconds until it popped loose again lol

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Get 3 new collars and line up the timming marks you should be good to go. Pretty simple system but you have to have those collars or gunna pop off every time. When take things apart be careful things don't fall out :thumbsup:

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2 hours ago, Dirtrider628 said:


I didn't know there was a spring. At least I didn't see one maybe that's missing too

There isn't a spring in the cylinder part of the system, only a couple in the centrifugal timer.

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There isn't a spring in the cylinder part of the system, only a couple in the centrifugal timer.

Oh ok. That has never been taken apart as far as I know so it should still be good. I did adjust it though. But it's missing the collars in the cylinder part of it sound the u shaped piece that turns the gears is loose, it moves forward and back and pops off. The parts are on the way so hopefully this will fix the issue lol. But thank you for the replies

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Get 3 new collars and line up the timming marks you should be good to go. Pretty simple system but you have to have those collars or gunna pop off every time. When take things apart be careful things don't fall out :thumbsup:

Yeah someone else took it apart before we got the bike, it's probably why we ended up with it so cheap because they couldn't get it running right lol. But the collars are on the way now that I know what was missing lol
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7 minutes ago, Dirtrider628 said:


Yeah someone else took it apart before we got the bike, it's probably why we ended up with it so cheap because they couldn't get it running right lol. But the collars are on the way now that I know what was missing lol

Easy fix them for cheap :thumbsup: that's how id look at it lol

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I presume the metal plate is still there that bolts into the cylinder (2 x 6mm bolts) and holds the control segment ( U shaped piece as you call it) in place is still there?  You need 6 of those 'top hat' shaped roller bushes, but presume you already have one on each pin if you've ordered 3.

Edited by 7Tktm

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Easy fix them for cheap :thumbsup: that's how id look at it lol

Absolutely! It did need a top end as well but we got the bike for 400$. So right now probably have 650$ in it which is a steal lol
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I presume the metal plate is still there that bolts into the cylinder (2 x 6mm bolts) and holds the control segment ( U shaped piece as you call it) in place is still there?  You need 6 of those 'top hat' shaped roller bushes, but presume you already have one on each pin if you've ordered 3.

Yeah the plate is still there, and I ordered all 6 of them but only 3 were there, and they were all on top of the control segment.

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