How To Rebuild the Top End on a KTM 85 SX

KTM 85 SX Top End Rebuild Parts

Learn how to rebuild the top end on your 2 stroke motorcycle. This video demonstrates how to easily replace the piston, rings and gaskets on your KTM 85 SX 2 stroke engine. We walk you through step by step on how to successfully rebuild and install the top end on your dirt bike.

KTM OEM Hard Parts
Cylinder Head O-ring Gaskets

0770800021 O-RING 80,00X2,00 VITON

0770540020 O-RING 54X2 VITON

GASKET SET CPL. 85/105SX 04
Part# 47030099100

47030035020 CYLINDER BASE GASKET 0,20MM | As Required

47030035030 CYLINDER BASE GASKET 0,30MM | As Required

47030035000 CYLINDER BASE GASKET 0,50MM | As Required

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[jonoj]

Didn't have my service manual with me but this vid having all the torque specs saved the day. Thanks heaps 😀👍

[nou]

piston pin puller? you mean a flathead and a rubber mallet?

[ryanmayer]

Dawg I put 178 hours on my piston on my 2018 ktm 125sx this season and there was no cylinder wear and the piston was in great shape. I don’t believe anything anymore lol

[Iatolaazzahola]

Top end replacement schedule is directly related to riding conditions and who is maintaining the air filter. I like the video. but why not go into servicing the power valve when you have the jug off? Critical maintenance area.

[Willthree]

how about a break in procedure video for 4 and 2 stroke.

[DYLLY]

That motion pro puller is just the company wanting money for unnecessary tools. Just ask someone to grab the piston for you and hit the wrist pin out with a mallet

[philipp]

I blew my piston on my 85 after 4 years of riding Almost every day

[peterhellmuth]

Hi great video I was just wondering if you had a video or pic how the power valve on the side goes back on and how the spring goes cheers

[jarenwilson]

I have a 1994 yz 80. I ride it several times a week wide open In a field and it has a stock piston 😂

[danmartens]

Any chance rmc has a video on internal power valve adjustments ?

[GiulianoDivirgilio]

You forgot one very important checking big end bearing for any play

[dirtmoto]

Every 10 hours??? My kdx topend can last 4-5 years easily.

[rsturborolphy]

Isnt it worth just putting a small beed of sealant round the base of the barrel? Now about to do the top end on my 09 85 . Ktm need to calm down on the production of the older bike parts getting hard to find bits for even earl 09 bikes. Got a quote on a barrel and piston...£600 ....my 98 cr125 top end is half of that 😂

[jesseanthony]

Dude I beat the absolute shit out of my ktm85sx and decided to do a rebuild on it since it was starting to loose compression and found out it has the original piston in it from 2004 kind of impressive tbh

[nicsminibikes]

Do you have a video of rebuilding the bottom end of a KTM 85 sx?

[speedtoad]

No honing cylinder or cleaning power valve? Interesting.

[jonthelamb]

First step should be wash the bike and take your time doing it

[tgsubie]

So you do no honing of any kind to the cylinder or piston sizing, not even mentioning it. This forces me to ask, for the common 85, would it be acceptable to replace the piston with a completely stock size piston?

[mustafanajm]

Thank u for the video i have question please i have this bike im going to repair the top end but what the different between oem top end and vertex top end please help thank you

[tomsharpe]

Will this be relatively the same for any other 85's? Specifically a yz85?