How To Rebuild the Top End on a KTM/Husqvarna/GasGas 250 & 300 2-Stroke TPI

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Whether you blew your bike up, are having a loss of performance or just want to refresh your engine for the riding season. Rebuilding the top end on your KTM 250 or 300 TPI is a great way to get familiar with your dirt bike and prevent catastrophic failures in the future. Knowing how to do the job correctly will save you tons of time and money compared to taking it to a shop. In this video, Charles shows how to rebuild the top end on a 2021 KTM 250XC, but this process will be similar for KTM, Husqvarna and GasGas 250 and 300 2-stroke TPI motorcycles.
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[@samadventures2160]

This video is aweosme I’m 14 an rebuilt my 2019 Ktm 300 exc all on my own Whatching the steps of this very detailed video 👍🏽👍🏽👌🏽

[@mguarin912]

Hell yeah kid. Nice work.

[@alfa955]

Holy shit my mom didnt let me ride a moped until i was 13

[@s30ztt]

And never rode the same or started up ever again, I'm the neighbor, glad he upgraded to a real bike a 4 stroke! At least it's quiet now😂

[@jeffcook8501]

When i was 8 years old my dad took a yz 125cc motor and put it in an 80cc frame and that is what I learned to ride on. Lets just say i learned respect for my bike quickly. Hit that power band, and it took off like a raped date. (as my dad would say)

[@jimg9942]

Great video Charles! EXTREMELY helpful to a guy who has not done a top end rebuild for 40 years!

[@rmatvmc]

Glad it helped!!!

[@mattcollins3572]

These are the best videos on the Internet.

[@batipapo]

Excellent video with all the detailed yet concise. Them circ clips look more like a puzzle.

[@anthonystruik1164]

Excellent video Charles, thank you. I just wish that inserting the piston circlip is as easy as you make it out in the video.

[@mschumaker1]

buy the EZ clips from Slavens. It's the only way

[@MikeHughesShooter]

Thank you. Excellent work. Ordered kit from you because of this video.

[@RICHIE_RICH89]

Start it up thats the best reward for pete sakes

[@jimbo4203]

My dad showed me how to rebuild a 2 stroke on my 78 Yamaha it 175 . I was 14 and she was running great afterwards

[@TwistandShout257]

Yeeeeoooowwwww! Great stuff Charles! Keep it comin 🔧

[@coffeeinthemorningsun2121]

Thank you for this perfect and detailed video 👍! Greatings from Germany!

[@DYLLY0456]

That’s crazy how you can get those clips in without scratching the piston at all, i did the top end on my 250 yesterday and scratched my piston on both sides🤦‍♂️ wish I had seen this video first that trick with the screwdriver would have made everything so much easier haha

[@ivandelavalle]

Best vid ever thanks so much

[@208enduro]

Phenomenal video. Thank you

[@WD469]

Great detailed information.

[@human1513]

Great video in many ways. Thank you for making it.

[@h3aDmAsTeR]

Thank you!

[@paulinebeckett2740]

Great video Charles but the only quality part on that KTM was the NGK Plug.

[@senor7857]

Spoiler alert: you are going to have nightmares with the piston circlips 😉😂

[@woodygamer9454]

Ez clips are your friend

[@isaacacers3986]

ive been having nightmares with the bloody piston rings cant seem to get them into the cylinder :/

[@LukeMorphett]

No kidding.

[@LukeMorphett]

Ezy clips sold out...

[@Jeff-pc1zu]

I would say this KTM is actually "oil injected" as opposed to fuel injection like the TBI is. If and when the oil pump goes this bike will seize up! TBI is a much better option as you still put oil in the fuel.

[@tuckeradams9225]

i wish you wouldn’t edit out the parts where you struggle. it makes it seem like it should be easy as pie when in reality it’s not that easy u just edited it out. be transparent shown it all!

[@ericdawson3425]

Thanks boys

[@rmatvmc]

Glad it was useful!

[@EricNeilson_]

No cussing! Miraculous.

[@tonyt1554]

Only because they edited part of him installing the wrist pin clips 😂

[@andreatreviso8049]

Nice job 👍

[@4JMcCart]

Shouldn’t you have added coolant and let it bleed through the temp sensor before putting the tank on? (I’ve done it with the tank on also)

[@ChrisKAloha]

Set the z before you put the cylinder on the bike. And if you don’t loosen the jam nut set screw you don’t have to reset it.

[@freedom7047]

super video

[@cornellgitman78]

anyone know why the KTM manual recommends "minor engine service" (piston head replacement) after 15 hours??

[@motosz255]

The retaining washer for the control valve in this video is triangle shaped. This is different that what is in the KTM exhaust valve blueprint which shows retainer plates instead. Where can these retainer washers be found?

[@corbettenders4257]

Great video, except you skipped checking the X-Distance... you show buying 3 base gaskets, how does your viewer know which one(s) to use?

[@corysargent5234]

Question: is it wise to run the oil relay to actuate the oil pump before the first start?

[@sebastianlassen8674]

Would like to see a piston change tutorial for the fe 501 2020 preferably🤣

[@rmatvmc]

We have a whole engine rebuild series for the 450, 500 and 501. You can check out the full series here: kzbin.info/www/bejne/npzEpqeqmsmmqKc Part 5 will show the top end assembly process, including piston replacement.

[@jakemassa8420]

Awesome video! I’m wondering, what steps are different when performing a top end on a 150 TPI?

[@rmatvmc]

Your 150 will be very similar to the steps shown in this video and this will be a great guide to have on hand for your rebuild. Thanks for checking out the video!

[@mastermat630]

what type of grease are you using ?

[@senor7857]

Tip: do not remove the middle screw in the right power valve mechanism, then you won't have to set Z dimension again

[@human1513]

But then you cannot remove the exhaust valve control shaft behind it to clean the shaft and cylinder in that hole and replace the "o"ring. So why do an approx. 90% job when the engine top is completely removed and being inspected & cleaned. As a mechanic / technician not doing this is considered being a hack.

[@senor7857]

yes, you can, at least in a 2020

[@ChrisKAloha]

The only reason you would need to set it is if you loosen the jam nut set screw. Even if you loosen the middle screw you still don’t have to set it.

[@redball4093]

Excellent video

[@henning_8246]

Please Help me: I cant torque the spark Plug because the cumbustion camber spins. What can I do?

[@norton218]

I have always been told to never use a ball hone in a 2 stroke cylinder because the balls can catch on the transfer ports and damage the cylinder. Is that not a issue anymore?

[@keshmo12]

That's 1 reason. The other reason is that the cylinders are nikasol coated and a ball hone can damage the coating. All you need to do is scotch brite the glaze off the cylinder and it's good to go. Some people say the nikasol coating is so hard that the ball hone doesn't hurt it. Ball hones are good for non -coated cylinders generally.

[@Triple9MX]

You skipped the one portion of video I’m looking for, how did you loosen the nut on the cylinder on the power valve side? I can’t seem to get a wrench in there with the rod in the way

[@rmatvmc]

Shoot, we removed ours with a box end wrench. It should fit between the rod and radiator hose. Pause this video and you can see where the wrench is at. kzbin.info/www/bejne/raivhHx6e8mJiJY -Charles

[@Triple9MX]

@@rmatvmc thanks for the reply, I'm wondering if there's thinner sized wrenches than what I have, I ended up having to remove the power valve mechanism to get it loosened. Thanks for the help.

[@lifewithabe312]

Would this be close to the same on a KTM 125?

[@csiautodetail]

this is a lot of work every 80 hrs.

[@STHusky]

One question can I over torque a bolt by 6-8ft-lbs more because my KDX 200 requires 18ft-lbs and my torque wrench is 25-250ft-lbs

[@rmatvmc]

We would not recommend it. There is a chance you can get away with it but there's also a good chance you break the bolt or cause other damage.

[@STHusky]

@@rmatvmc ok thanks

[@timslucky]

One thing I haven't seen in any video is the orientation of the ring gaps. Is there any particular best position in the cylinder and are the two ring gaps offset 180deg from one another or what. What is common practice?

[@robbiechiles36]

their are pins in the ring land that orient the rings.

[@timslucky]

@@robbiechiles36 Thanks. Yep I found them, and she's running great.

[@jacksonbuck7481]

Your website sells two different OEM piston kits for the 2022 TE300i. Which kit do I need to buy? Kit #1 or Kit #2?

[@rmatvmc]

You will want to take off the exhaust control cover on the right side of your cylinder and see which number is stamped on it. Then you can order the corresponding piston. We have a short video explaining more about this here: kzbin.info/www/bejne/rajRnHt_m5V5bdk

[@MrSTEALTH125]

what is that cleaner you are using on the power valve? I've tried oven cleaner and carb cleaner and it is still a lot of work compared to what you show in the vid

[@rmatvmc]

That's the Polaris Carbon Clean Fuel System Cleaner. You can check it out here: www.rockymountainatvmc.com/parts/polaris-carbon-clean-fuel-system-cleaner-p

[@KhatanbaatarBuyantogtokh]

how to repair cylinder my cylinder has a so many scratches. can you teach

[@rmatvmc]

We have a video showing how to inspect your cylinder and how to repair it if possible. You can check that out here: kzbin.info/www/bejne/f5_JgaFmgtmChrs

[@brandonshreve3201]

OEM parts lists a piston 1 or 2, how can you tell which one to use?

[@rmatvmc]

You will have to check the piston that's in your bike. It should be stamped with a 1 or 2.

[@cliff1551]

You forgot the bolt on the left side arm mate

[@mathieu6514able]

At what time you saw that in the video?

[@AustinM-wf5nk]

What kit would you guys recommend for a 2021 husky 300 tpi with 112 hours on it?

[@rmatvmc]

We used the Vertex piston kit for this rebuild and have had good luck with them. Also, the Pro X top end gasket kit will come with all the gaskets and seals you need so you don't have to dig through the OEM parts finder and find them all individually. The first link in the video description will take you to a page where you can see all the parts and tools that are needed.

[@davidalexandru9176]

How to choose the corect piston size?

[@rmatvmc]

kzbin.info/www/bejne/bGGQiKd8j89rd7M Here's a link to our Piston to Cylinder Wall Clearance video.

[@andreatreviso8049]

Subtitle Italian please

[@alstar300]

When deciding on a base gasket height, would it be ok to just reuse the same size as the one(s) you pulled off?

[@rmatvmc]

Not necessarily. That might be a good starting point, but the reason you'll want to check the deck height is because the new parts can vary slightly due to manufacturing tolerances. I'd recommend checking it to avoid problems. -Charles

[@bloomerb4162]

My 300, the previous owner had a .025 cylinder gasket. That's way off from factory. I was worried but I knew the previous owner had a mechanic do it, so I put same size back in. It turned out ok.

[@otmuppet]

All about squish. You can fine tune your squish via base gasket. Most two strokes are built way too loose. Only fix is shaving the head

[@nickyyoung1992]

The smaller base casket more compression more power.

[@enduroa.k.o]

What size piston did you go for at 80h ?

[@rmatvmc]

We used the Vertex piston which is 66.35 mm.

[@kordapyo612]

28:35 why does both piston ring ends are aligned?

[@onthethrottle7104]

Look at 28:14 in the video..

[@andrewcooksey2255]

@@onthethrottle7104 not true. there is a locator pin for the rings on 2 strokes. If not, the ring could rotate and the end get caught in a port.

[@bobes919]

Where do you find a Z dimension tool from ?

[@rmatvmc]

www.rockymountainatvmc.com/search/go?w=decking%20and%20timing%20tool%20

[@rmatvmc]

The first link in the description of this video will take you to a page with all the parts and tools use in this video including the Tusk Deck and Timing Tool.

[@bobes919]

@@rmatvmc thanks

[@wanmuhammadfakhrullahwan8078]

,👍👍

[@alin2107nicholas]

Hey charles I'm wondering, if I buy the base cylinder gasket off the OEM diagram, do I get different sizes or just one gasket?

[@CharlesTheWrench]

Scroll down to #22 on the parts list or whatever number it shows for your bike, and you'll have about six options. The last two numbers in the part number should be the thickness in mm. so .20mm-.75mm. -Charles

[@alin2107nicholas]

@@CharlesTheWrench thanks a lot!

[@richardhartley7094]

What size was new piston A or B👍🇬🇧

[@tonyt1554]

Torque the cylinder to spec......as he uses a combination wrench 🤣

[@jurgenjurgendebono4007]

80 hours are way to early to change the piston

[@sakariputtonen2683]

By the manual..

[@michaelwcarpenter5824]

@@sakariputtonen2683 Still way to early to change rings or a piston!

[@onthethrottle7104]

@@sakariputtonen2683 Manual states 80-100 hours.

[@MAXlMUS]

KTM just making sure they have something to eat 😁

[@cfilmz_tv7769]

Definitely not that easy for the wrist pin clip

[@Ridefastorgetpassed]

Another POS Kymco cylinder. Shame on KTM.

[@fullyrc8555]

Dam my 2014 ktm 450 is more simple than this top end rebuild! And they say 2 strokes are easier

[@gophop]

The whole thing about 2T top end jobs being simpler than 4T is such a meme. Would rather set cam timing than do all this crap.

[@MAXlMUS]

You're not choosing between 2T/4T based on this aren't you?