Very informative Video! Another great option is a cylinder exchange program. We send you a Millenium Cylinder and charge a core charge, when it arrives you throw your old one in the box and send it back, and get the core charge back when your old cylindee arrives. Faster turn around times and a great alternative to a new cylinder. Replating turn around times can be huge, especially this winter with the amount of sleds blowing up, there actually a shortage of replated cylinders for some sleds!
Why not just replate the cylinder with nikasil and get it adjusted with the new piston and run 32:1 as the Honda manual said? They designed this engine and they recommand 32:1... why not just follow the recommendation of the Honda engineers????
That is not what detonation looks like all of those heads had been torn up by needle bearings coming out of the crank or contamination. When a motor pings alot it looks like you sand blasted the inside of the head. Makes it have a rough sandpaper like finish.
3:09-3:20 so called "detonation" is mostly broken off electrode tip from the spark plug and/or piston ring chips that have banged your head to crap :) Sure there can be some spots but those deep grooves ARE steel chunk made. I had that happen to my head after I broke my rings that caught my YPVS, identical to these pics ;)
Hello, One quetion: what kind of metal did you put in cylinder to measure after compresion piston and cylinder gup and what mm must be there in ideal condition? 0.155mm ?
Excellent documentary very good advice, the only thing I would have added is how important it is to keep your air filter clean and properly maintained thank you.
Nice video, but the detonation does not cause the “chisel marks” in a (trashed) head, it is from a circlip that came out of the piston to hold in the piston pin
Mxrider2stroke Braaap sorry for the confusion. I didn’t have this all scripted beforehand (I didn’t even know what to do with my hands when I was on camera 😂). Detonation marks typically look like a bunch of small round punch type marks, not chisel. You’re right, flat chisel type marks would be more sign/result of part of a ring, or other debris getting in between the piston and head. Thanks for keeping me honest!
3:31 Amsoil Saber on the bench..... I'm guessing yall ran a lean oil mix. With these old 2 strokes, you better run Amsoil Dominator 32:1. And yes I do think you will find my oil advice useful... Considering the demonstrated results of not doing so.
Piston and cylinder got hot from lack of lubrication. Excess heat causes detonation. Don't believe me? Run saber 100:1 in that bike again. Youll believe me when you're pushing that bike home.
Detonation marks are typically more of a small, round punch type mark but it definitely does leave indentations in the top of the the piston and in the head, normally on the outside, flat portion of the head (not the dome). Sorry for the confusion.
Are the ktm 250 exc 2015 and ktm 250 exc 2018 is have sam frame and subframe ? Please help me, i wanna change my old 2014 plastic to used the new plastik of 2018 .. hope u answer so im not getting buy wrong think 🙏
So now you are giving the bike away and I take from your last ride, you didn't get it right how you wanted. Are you calling this experiment a failure (no offense at all). Is there anything else you would have done differently or anything else you might have done if you were to go forward with it? Really asking because I am thinking about this same road you just went down.
Lol I'm not taking any top end tips from a guy who runs 100:1 premix and who puts in the wrong sized piston after spending over 8k to restore a race (not trail) bike...
@@tijn3243 😂 I repair my own bikes fool. And I stick with mostly two strokes, sold off the two four stroke 450s, now it is 250 and 500 two strokes only (with a 06 worked up special edition last year banshee ever made). It is not hard to cross hatch a cylinder and replace the piston...any new piston kit regardless of brand comes with the new bearing, circlip, and hardware needed. If you use a wiseco piston you need to drill two small holes on exhaust bridge side (oil cooling ports). Cleaning power valves on bikes that have them is a breeze too (his 03 has the electronic power valve so it is crucial to keep the proper tension on the cables, very easy to adjust). And if you send your cylinder out to a shop for repair like exhaust bridge crack, a resleeve, or replate, you would send them the piston too... The 03 cr250r has two different (stock) piston sizes that are slightly different in size by micro amounts they label them A or B on the piston... It's not rocket science buddy..
Jesus, if you're going to take a shot at a guy at least make sense. Kyle didn't do the top end himself, he hired a mechanic. And he's not giving out any tips in the video, he's asking questions of a different mechanic.
@@Vanir03 ovbiously not a very qualified mechanic..that is what happens when you go to a mechanic or stealership. They screw you over and shrug their shoulders trying to say it wasn't their fault and that (you) the owner must of messed it up. Buy a repair manual and do the job yourself, this day of age there is so much information around, I'm sure he has a torque wrench and any other tools needed to do the job himself..
When I seized the top end on my yz250 likely due to running too lean on the oil (60:1), I decided to replace the cylinder because it was not much more money on Parzilla.com. I think new OEM was $350, to nikasil plate old cylinder was $250. They really need to be priced lower for that service. I learned my lesson and keep it around 35 to 40:1.
@KGB 1974 good idea. Well, I was spooging quite a bit, so I figured use less oil. My mistake. I have now switched to amsoil interceptor and I'm happy with the results, at 35:1
Why can't they take it oversize to clean it up? It seems to me that would be easier and cheaper than welding and attempting to keep the bore standard. Is the wall thickness too thin and it would lead to overheating? I understand why you went new in this case but it seems boring to next oversize wasn't considered and I'm curious why. Understand I'm used to dealing with Harleys, automotive, and aircraft engines where oversize in not uncommon.
Ron Hunter these cylinders are plated, and if you bored it over you would have to have it plated again. Less expensive to just have it plated without boring it.
I’m pretty new to dirt bikes so I don’t know much about rebuilds, do I need to send the cylinder in for work every time I get a new piston or just if it’s showing signs of wear?
@@jaybo3687 not that it matters but I own a KTM and Yamaha YZ250X. Personally I prefer the Power Delivery of of the YZ. My original post has nothing to do with bike brands and rider preferences i was simply stating that adding a big bore will make the old motocrosser more trail oriented. Second post was merely stating that a reliability test on a big bore would be very interesting.
@@jaybo3687 actually everything you just said. I prefer the more aggressive hit. I want the hit to get over logs, rocks and such. I geared the bike down added exhaust system and V-force reeds all which gave it a bit more low end torque. I know everyone thinks of KTM as the holly grail and honestly it gets a bit old. Yeah its a good bike and perhaps in extreme slick conditions I would prefer my KTM to the Yamaha but in most cases I do not. Motor aside I also prefer the plush suspension of the YZ and the egros Yamaha fit me better. However I did have to add bar risers.
Great vid and a nice bike!! would love to win a cr but im guessing that's not possible when you live on the other side of the planet? im sure shipping cost would out weigh the cost of the bike. thumbs up any how. 👍
Richard Stremlow most 250s we set close to .045” or a little more to avoid running race gas (but it smells so good!!). You’ll get more life out of your crank and top end in general with more clearance.
Lance G. I should’ve said small punch marks. Sorry for the confusion but thanks for correcting me! It was my first time on camera in front of 130k subscribers 😰.
I wish Kyle would explain why he keeps saying it was only a little more cost to buy a new cylinder, if he is telling the truth and this bike seized because the cylinder was the wrong size for the piston then whoever replated the cylinder should be replating the cylinder and replacing the piston for free.
John Lastname This is Kevin with MotoXperts. We were able to find a brand new OEM cylinder for just over $300 and it was on the shelf so we went that route. We didn’t do the last top end on the bike but my understanding was that the cylinder was sent to Millenium and the piston was purchased separately. Wasn’t the plater’s fault, wasn’t the piston’s fault. It was simply assembly error, putting a B size piston in a tight cylinder.
@@kevinegbert1251 Kevin thank you very much for the clarification I thought you guys had the last replate done I was not aware that it was done by the previous owner and that makes MUCH more sense now, you guys should clarify that in a future video I'm sure I'm not the only one that was wondering this.
@@kevinegbert1251 Eric used to be the head guy for honda race teams back when they used to race the cr500r (500 class). Published several books, defiantly knows his stuff. Had him rebuild one of my 1991 cr500r engines top to bottom, freshly powdercoated, stainless steel hardware, and he welded and lapped the cases after the previous piston exploded and caused a hole. Had him also turn it to a real animal (ported and polished).
I keep seeing people saying you ran 100/1 . Could you please put to rest if this was the case or if you pre mixed 32/1. I know with newer type oils maybe get away with less but I am not sure this would be the case.
I believe he’s said in the past he runs 40:1 or 50:1, 32:1 is pretty rich for most bikes that I’m aware of, it’s ok for break ins but you’ll foul plugs way quicker with a 32:1 mix
@@michaelparker9918 Ok I run caster 927 at 36/1 in my cr250 now if your coil or cap it bad you will faul plugs. Coil 5.5 ohms Wire 5.5 ohm Cap 5.2 to 5.4. Lower that 5 ohm no good. All three together 10.5 to 11 Is good. Ok I run a CRF 450 MEB coil 2002 to 2008 TRX 450 2002 2008 replacement coil for the kz4 2000 to 2007 cr250 Hotter spark cleaner burn.
If you follow him you see he is a fan of amsoil saber at 100 to 1. I actually called amsoil and they told me they don't recommend it in bikes, just for small engines ala weedwackers etc. Unsure what he was running when it blew up though, would like to know
@@ericahearn9604 Well that oil dose not lubricate the motor that well. You see what the Piston looks like on the intake and the exhaust side. Look on my CR250 Mikuni 40mm carburetor video.
Very informative Video!
Another great option is a cylinder exchange program. We send you a Millenium Cylinder and charge a core charge, when it arrives you throw your old one in the box and send it back, and get the core charge back when your old cylindee arrives. Faster turn around times and a great alternative to a new cylinder. Replating turn around times can be huge, especially this winter with the amount of sleds blowing up, there actually a shortage of replated cylinders for some sleds!
Why not just replate the cylinder with nikasil and get it adjusted with the new piston and run 32:1 as the Honda manual said? They designed this engine and they recommand 32:1... why not just follow the recommendation of the Honda engineers????
Thank you ... 😁😁 I love you people I love my cr125 to has never did me wrong
3% everywhere, never fails if the motor is right :)
Sleeve it, bore & hone it to spec. The cylinder will outlast the crank.
That is not what detonation looks like all of those heads had been torn up by needle bearings coming out of the crank or contamination. When a motor pings alot it looks like you sand blasted the inside of the head. Makes it have a rough sandpaper like finish.
3:09-3:20 so called "detonation" is mostly broken off electrode tip from the spark plug and/or piston ring chips that have banged your head to crap :)
Sure there can be some spots but those deep grooves ARE steel chunk made. I had that happen to my head after I broke my rings that caught my YPVS, identical to these pics ;)
Good choice just going with a new jug!
Hello, One quetion: what kind of metal did you put in cylinder to measure after compresion piston and cylinder gup and what mm must be there in ideal condition? 0.155mm ?
Excellent documentary very good advice, the only thing I would have added is how important it is to keep your air filter clean and properly maintained thank you.
Love to win the bike
Love to win this bike thank you.
Nice video, but the detonation does not cause the “chisel marks” in a (trashed) head, it is from a circlip that came out of the piston to hold in the piston pin
Mxrider2stroke Braaap sorry for the confusion. I didn’t have this all scripted beforehand (I didn’t even know what to do with my hands when I was on camera 😂).
Detonation marks typically look like a bunch of small round punch type marks, not chisel. You’re right, flat chisel type marks would be more sign/result of part of a ring, or other debris getting in between the piston and head.
Thanks for keeping me honest!
Haha cool, thanks for the response:D
Langcourt is probabably this best in the business as far as cylinder restoring/ replating
Brand new top end just burned up after less than 15 hours. Looks like bad gas hoping to salvage the cylinder from cylinder works.
What piston and what oil and what ratio and what jetting did you run? Video would be a lot more useful if we had actual info.
3:31 Amsoil Saber on the bench..... I'm guessing yall ran a lean oil mix. With these old 2 strokes, you better run Amsoil Dominator 32:1. And yes I do think you will find my oil advice useful... Considering the demonstrated results of not doing so.
Piston and cylinder got hot from lack of lubrication. Excess heat causes detonation. Don't believe me? Run saber 100:1 in that bike again. Youll believe me when you're pushing that bike home.
Kevin is a super cool guy. Would like to see some rides with him :)
detonation does not chisel mark the head eating rings does that :-)
Yes thats true but the chisel type marks do cause detonation because the little specs heat up alot and your fuel will combust to early!
Detonation marks are typically more of a small, round punch type mark but it definitely does leave indentations in the top of the the piston and in the head, normally on the outside, flat portion of the head (not the dome). Sorry for the confusion.
@KGB 1974 or even needle rollers from the little end get chucked up through the transfer ports but not detonation
Exactly my thoughts. What they showed is foreign debris not detonation.
Are the ktm 250 exc 2015 and ktm 250 exc 2018 is have sam frame and subframe ? Please help me, i wanna change my old 2014 plastic to used the new plastik of 2018 .. hope u answer so im not getting buy wrong think 🙏
So now you are giving the bike away and I take from your last ride, you didn't get it right how you wanted. Are you calling this experiment a failure (no offense at all). Is there anything else you would have done differently or anything else you might have done if you were to go forward with it? Really asking because I am thinking about this same road you just went down.
Lol I'm not taking any top end tips from a guy who runs 100:1 premix and who puts in the wrong sized piston after spending over 8k to restore a race (not trail) bike...
Gsxr-1000 Rider that why your listening to the fucking mechanic and if you don like it go watch someone else
Just listen 2:42 and 2:52 done! You can keep taking the tips bro.
@@tijn3243 😂 I repair my own bikes fool. And I stick with mostly two strokes, sold off the two four stroke 450s, now it is 250 and 500 two strokes only (with a 06 worked up special edition last year banshee ever made). It is not hard to cross hatch a cylinder and replace the piston...any new piston kit regardless of brand comes with the new bearing, circlip, and hardware needed. If you use a wiseco piston you need to drill two small holes on exhaust bridge side (oil cooling ports). Cleaning power valves on bikes that have them is a breeze too (his 03 has the electronic power valve so it is crucial to keep the proper tension on the cables, very easy to adjust). And if you send your cylinder out to a shop for repair like exhaust bridge crack, a resleeve, or replate, you would send them the piston too... The 03 cr250r has two different (stock) piston sizes that are slightly different in size by micro amounts they label them A or B on the piston... It's not rocket science buddy..
Jesus, if you're going to take a shot at a guy at least make sense. Kyle didn't do the top end himself, he hired a mechanic. And he's not giving out any tips in the video, he's asking questions of a different mechanic.
@@Vanir03 ovbiously not a very qualified mechanic..that is what happens when you go to a mechanic or stealership. They screw you over and shrug their shoulders trying to say it wasn't their fault and that (you) the owner must of messed it up. Buy a repair manual and do the job yourself, this day of age there is so much information around, I'm sure he has a torque wrench and any other tools needed to do the job himself..
When I seized the top end on my yz250 likely due to running too lean on the oil (60:1), I decided to replace the cylinder because it was not much more money on Parzilla.com. I think new OEM was $350, to nikasil plate old cylinder was $250. They really need to be priced lower for that service. I learned my lesson and keep it around 35 to 40:1.
@KGB 1974 good idea. Well, I was spooging quite a bit, so I figured use less oil. My mistake. I have now switched to amsoil interceptor and I'm happy with the results, at 35:1
Why can't they take it oversize to clean it up? It seems to me that would be easier and cheaper than welding and attempting to keep the bore standard. Is the wall thickness too thin and it would lead to overheating? I understand why you went new in this case but it seems boring to next oversize wasn't considered and I'm curious why. Understand I'm used to dealing with Harleys, automotive, and aircraft engines where oversize in not uncommon.
Ron Hunter these cylinders are plated, and if you bored it over you would have to have it plated again. Less expensive to just have it plated without boring it.
Nikasil is a bitch 👍. He can replace the cylinder or if he chose he could even get it resleeved but that is not the best option.
I’m pretty new to dirt bikes so I don’t know much about rebuilds, do I need to send the cylinder in for work every time I get a new piston or just if it’s showing signs of wear?
Just when showing wear.. which I’m sure you figured out by this time lol
Add a big bore. More trail oriented
@@jaybo3687 False, a larger bore can be just as reliable as a stock bore engine
That would have made for a good series on this older bike. Big Bore Kit tested for reliability.
@@jaybo3687 not that it matters but I own a KTM and Yamaha YZ250X. Personally I prefer the Power Delivery of of the YZ.
My original post has nothing to do with bike brands and rider preferences i was simply stating that adding a big bore will make the old motocrosser more trail oriented. Second post was merely stating that a reliability test on a big bore would be very interesting.
@@jaybo3687 actually everything you just said. I prefer the more aggressive hit. I want the hit to get over logs, rocks and such. I geared the bike down added exhaust system and V-force reeds all which gave it a bit more low end torque. I know everyone thinks of KTM as the holly grail and honestly it gets a bit old. Yeah its a good bike and perhaps in extreme slick conditions I would prefer my KTM to the Yamaha but in most cases I do not. Motor aside I also prefer the plush suspension of the YZ and the egros Yamaha fit me better. However I did have to add bar risers.
Love the vids keep it up
I didn't realize the old cr250r had power valves.
Put a sleeve in it???
Great vid and a nice bike!! would love to win a cr but im guessing that's not possible when you live on the other side of the planet? im sure shipping cost would out weigh the cost of the bike. thumbs up any how. 👍
ONE person will win BOTH bikes, or TWO people will win ONE bike each?
I’ve heard the cylinder needs 3000 of a gap between it and the piston. Is this true here
Richard Stremlow most 250s we set close to .045” or a little more to avoid running race gas (but it smells so good!!). You’ll get more life out of your crank and top end in general with more clearance.
Sorry detonation does not put chisel marks in the head! FOD does that :)
Lance G. I should’ve said small punch marks. Sorry for the confusion but thanks for correcting me! It was my first time on camera in front of 130k subscribers 😰.
Detonation does indeed cause the damage seen on that cylinder head.
I wish Kyle would explain why he keeps saying it was only a little more cost to buy a new cylinder, if he is telling the truth and this bike seized because the cylinder was the wrong size for the piston then whoever replated the cylinder should be replating the cylinder and replacing the piston for free.
John Lastname This is Kevin with MotoXperts. We were able to find a brand new OEM cylinder for just over $300 and it was on the shelf so we went that route. We didn’t do the last top end on the bike but my understanding was that the cylinder was sent to Millenium and the piston was purchased separately. Wasn’t the plater’s fault, wasn’t the piston’s fault. It was simply assembly error, putting a B size piston in a tight cylinder.
why not run honda piston, with my many 2 strokes over the years mostly Honda's, honda OEM parts are way better than wiseco or prox
@@kevinegbert1251 Kevin thank you very much for the clarification I thought you guys had the last replate done I was not aware that it was done by the previous owner and that makes MUCH more sense now, you guys should clarify that in a future video I'm sure I'm not the only one that was wondering this.
Tom Fischer #notshipping on all OEM pistons for the 2002-2004 CR250R. We checked multiple dealerships and online OEM parts retailers.
Send it to Eric Gorr for a big bore and porting.....quit f#$#in around
Mo better 👍. Eric does excellent work (takes him a little while but the wait is worth it).
Eric does great work. We’ve had great results with his big bore kits and port work.
@@kevinegbert1251 Eric used to be the head guy for honda race teams back when they used to race the cr500r (500 class). Published several books, defiantly knows his stuff. Had him rebuild one of my 1991 cr500r engines top to bottom, freshly powdercoated, stainless steel hardware, and he welded and lapped the cases after the previous piston exploded and caused a hole. Had him also turn it to a real animal (ported and polished).
Gsxr-1000 Rider I had no idea! I’m not surprised though, the guy is a genius.
I keep seeing people saying you ran 100/1 . Could you please put to rest if this was the case or if you pre mixed 32/1. I know with newer type oils maybe get away with less but I am not sure this would be the case.
I believe he’s said in the past he runs 40:1 or 50:1, 32:1 is pretty rich for most bikes that I’m aware of, it’s ok for break ins but you’ll foul plugs way quicker with a 32:1 mix
@@michaelparker9918
Ok I run caster 927 at 36/1 in my cr250 now if your coil or cap it bad you will faul plugs.
Coil 5.5 ohms
Wire 5.5 ohm
Cap 5.2 to 5.4.
Lower that 5 ohm no good.
All three together 10.5 to 11 Is good.
Ok I run a CRF 450 MEB coil 2002 to 2008
TRX 450 2002 2008 replacement coil for the kz4 2000 to 2007 cr250
Hotter spark cleaner burn.
If you follow him you see he is a fan of amsoil saber at 100 to 1. I actually called amsoil and they told me they don't recommend it in bikes, just for small engines ala weedwackers etc. Unsure what he was running when it blew up though, would like to know
He Runs 100:1 amsoil saber...Just like Jeff Slavens and many others
@@ericahearn9604
Well that oil dose not lubricate the motor that well. You see what the Piston looks like on the intake and the exhaust side.
Look on my CR250 Mikuni 40mm carburetor video.
I would love to see you and EVERide do a video together! can we make this happen?
Can u be in europe to win a bike?
The problem is the oil
Dammm this guy talking over the first start footage
Chicken dinner
Winner winner
Is this the same guy that put the wrong sized piston in it?