Why Do Engines Blow Up? 

Share your blown engine stories!

Dat feeling when ur engine blows up and u have to push ur bike 10km to home. Rips man inside very well.

I love how in depth you get in your videos. I learn something new every video I watch. Can’t wait to see the rebuild on Jeff’s 250 and the engine build on yours too!

Short answer, because Devin rides them.

ChrisFix of motorcycles

My 2-stroke 125cc heat seized one time but after it cooled down.. it worked completely fine and still is... I ride it everyday. The compression is the same as it was before

I just picked up an 03 CR250R. its in good shape, all the frame bearings were replaced as with the rims and hubs. The more of Cameron's videos I watch the more I want to spend on mine! Damn you Cameron!

For competition worth using a dial gauge every tear down and measuring things like con rod side deflection and piston height as well as regular checking of valve clearances. For example in a 2t every time you swap rings, measure side to side rod defection so see how the big end is going as well as rinse out of the casing the see if there is any debris sitting at the bottom. Color of the piston underside, signs of ash. Main bearing radial and side deflection. Measuring valve clearances can give early signs of some change to the valves that can indicate impeding failure. Measuring piston height at exact TDC can show up signs of con rod stretching.

Coming from a newb your videos are extremely helpful, high quality and well presented. Keep up the great work!

The piston on my cr500 recently blew apart ruining the crank and luckily nothing else really was damaged (except a few dents on the cases but nothing to worry about) and your videos have been really helpful on learning what I need to do to rebuilt the engine. For now on I will always take the cylinder off to inspect the piston and crank on every used bike I get.

Never seen a bent/broken rod in a CRF 50. Seen some no oil/seized pistons. That tiny piston with the bent/fractured rod looked weird. Thanks for sharing.

4T or 2T Im switching to ROTARY😂

2010 Suzuki DR-125SM. 150cc kit, ported cylinder head, bigger fuel injector, open airfilter and Black widow GP exhaust system. Banked 23.7hp on the rear wheel with 27Nm ft-lb of torque. Previous owner never bothered to check the oil retainer. about 3500km on the new build and the cylinder head exploded due to the amount of gunk that was in the filter behind the oil retainer, no oil was flowing trough the system anymore.. Camshaft and rocker arms were blue from the heat and completely bent. Piston expanded and the crown got stuck beyond TD, the connecting rod pulled the rest clean off the crown. Both valves were snapped. Amazingly enough, the crankshaft is undamaged, the crank balancer is bent however. This all happened in about 1 second on the highway going 140km/h trough a slight turn. I think I can thank god for not throwing my gearbox and still being able to roll her out with the clutch.

When is the video coming out of jeffs bike getting rebuilt.

I change my oil 1 to 2 times a year and i also do a lot of riding lmao

Cameron love your stuff mate, I am an AUssie based in Phuket Thailand, we ride singke track in the jungles and mountains, my main bike is a KTM 525 EXC setup for tight single track (many mods) amd I also have (had) a CRF2050L with Takegawa 305 BB kit, EJK controller, Yoshi (clone) pipe, YSS susoensions mods and Renthal bars.. its went like a rocket, ran perfect ridden hard offroad only, was my backup bike and also for short adventure rides, was setting it up for longer trips .. THEN DISASTER .. i burnt clutch plates stuck in mud, a new mechanic replaced clutch plates, oil change etc and first easy 20 mins it blew to pieces at 120km slow cruising on a road trip, TOTAL destruction - pieces of metsl csm out the top of the crankcase (scary), pulldown revealed the worst news - full rebuild needed - 2 crank cases, cylinder , head, , valves, piston kit, etc (I can post pix link if anyone interested). Made no sense, its was an awesome engine, ridden hard offroad with zero problems, until then... mames me wonder if something done when last worked on caused it as seems big coincidence! anyway i dont want to go back to a stock 250 as I liked the 50% more power it had (my other bike is a KTM 525 EXC), I dont want to do the BB or Takagawa kits as I prefer to keep all Honda parts as when on advenrture rides all over SE Asia, will be easy to get parts. SO .. I am trying to decide between a rebuild using CBR 300 parts, or a full CRB300 engine transplant, or another that fits fairly easily. As I live in Thailand the CRF parts are cheap as they all made here, so thats a plus. Can you offer your thoughts? Anyone else done similar?

Great video! Yeah the oil change, coolant, air filter is a must do, you won't be riding for a long time without changing it. 💥

Great video! A too early ignition timing can also lead to a hole in the piston I believe

So it’s been like 3 weeks since the last CR250 upload? So................

Your videos are the best man. I always tell my bros to check out your advice. In so happy your doing well. Lots of respect from Akwesasne.

Hey Cameron been watching your videos for awhile and want to recommend something. In your editing software try and level out the sound and raise the volume. Volume is too quiet and too loud at some points. Mostly too quiet. But leveling out the volume would help so I don't have to keep turning up and down my volume. Just a recommendation I still really enjoy your videos as they are.

Maxima is definitely in my opinion the best oil that is available almost everywhere

Very helpful video Cameron, keep it up bro, don't worry about the CR, parts will get there soon enough.

Hey I love your videos!! Can you make a video on how you got started parting out dirt bikes and how someone can start doing it themselves?

Everyone always talks about how much cheaper a two stroke is to rebuild but never consider how many more hours you get out of a four stroke. If you pay for a complete 2t rebuild you’ll pay around 500-800 depending on how you do it and a 4t will most likely be 600-1000. You’ll pay more for the 4t but will get 50 more hours before having to do it again, if you build your own motors it doesn’t matter then. 🙃

Yesterday i bought a new bike, went out for a ride and it ran great. Today i also went for a ride and suddenly the engine shut off and there were quite a bit oil dripping, I checked for leaks and i saw that the drain bolt weren't there... I had to roll it home (2km) but hopefully nothing have blown.

What could you do to prevent a connecting rod from snapping? After About how many hours would you recommend rebuilding the top end and how many hours on the bottom end? Thanks 👍

I think that 'how to' videos are the best. Especially with 4 stroke engines! Thanks for the videos!

It also depends on how hard you push it each trip. How long etc

Just keep doing what your doing. Maintenance, how to videos and riding videos. I'm not getting bored.

with coolant also a water pump failure, i had a yz250 blow during a desert race due to a water pump failure, figured i was 50 hard hours into a top end and in 5th gear wide open in the hot desert and didn’t check my water pump. learned it the hard way and barely caught it running hot before it seizure still had cylinder damage....

Quality of coolant won't cause any failures, you can run any fluid thin in a radiator and it will be fine. I don't suggest that but we get your point. Other why's great video.

Well my 85 just went through it’s 6th top end today I don’t know why it keeps blowing up most of the time I’m not even wide open and I just put a new top and bottem end about 2 days ago 😤

I have a very puzzling problem with my bike. Only 16 000 km, bought new, always state of the art tuned and maintained . I drive it with care and never push it to its limits. I'm the only driver and noboby else has access to that bike. That bike always give a great service and satisfaction until 2 weeks ago, as I noticed that the engine oil was low. I always used Motul 4w40 Synthetic oil. So I filled up back until the oil level was full and went back on the road. After only 65 km, I checked back the engine oil level and the oil level had dropped to the half. Thinking the oil filter could be in trouble and making the engine oil pressure to open the oil pressure relief valve causing oil to be burned, I changed the oil and the oil filter. I filled back the engine with the requested 4.6 L of Motul 4w40 Synthetic. One hour later in the garage, while the engine did'nt run, at my surprise, the oil level was less than the milldle of the oil stick. I filled up back, adding 1 more liter of oil. I runned the engine for a couple of minuts to be sure that the new OEM oil filter would be full. Then I went home to sleep. The next morning, I went to the garage and once again the engine oil level was a bit over the minimum. I added again oil. Now I filled up my bike with a total of 6 liters of engine oil even the user manuel and the service manual say that it takes not more that 5.1 Liters when the engine is completly dry. That bike don't leak, never leaked and doesn't smokes when I drove it for testing in order to discover why that engine oils is disappearing. Where that oil can go into the engine, if it is not burned, it doesn't go on the ground ? Does somebody from you have a clue to help me. Over that, the engine always runned well and gived good performance and still runs well. Thank you very much. It's a 2013 Nomad 1700 cc. I would appreciate any idea that could help solve this puzzling mechanical situation.

I blew my engine today on a cr450r for the second time going around 90mph maxed out , in the desert had to leave my bike in desert and get my truck becuase no service

Rod snapping on the 250 is rod fatigue from bouncing of the rev limiter being ran too long. Rev limiter cuts spark and without the combustion event to ‘cushion’ the piston @ TDC when it needs to change direction. This accelerates fatigue in the rod @ it’s weakest (smallest cross section) point, or below the piston pin.

I had a small Ninja Pocketbike when I was a kid that I sort of modified and I always used to go to a abandoned small runway and raced with friends. It’s brought up quite a bit in racing. Never drain the oil in a race! You’ll lose! Haha

first day i got my motorcycle license, i took my 06 thundercat about 10 miles from home doing 60 mph on the highway when i hear a bunch of clanking and the bike dies. was stuck for 2 and 1/2 hours before i got home lol

Me: hasn't changed my oil in 3 years, has overheated my atv multiple times, has never changed my gear oil, and has never changed my air filter. My 80cc yamaha raptor from 2003: has literally no problem with it

2010 crf250r...bought used rode it 30 min..grenaded th motor..same story of needle bearing cage coming apart..like ur buddy Jeff very common..1 Hot Rod stroker crank kit later..still going strong...

lmao, i have a drz 125 and i haven't changed the oil in 4 or 5 years, doing it soon tho

Had a valve drop on my rc390 once, needed a whole new top end as well as a remap to match the exhaust I had put on it, expensive mistake to learn from, don't just add an exhaust without remapping

Can you explain why cam chains blow up on 4 strokes and how to prevent it?

Why did you stop using Rotella oil

Last Spring my crank shaft snapped :( had to push it home lol

Hi Cameron, wish to see more races on the channel too. Here to support you! Always amazing contents in your videos!

2-strokes tend to seize after a while when people let off the throttle, but keep the bike is gear which deprives the engine of it's main source of engine oil.

Great video Cam !! Thanks

At one of my races there was a kid revving his bike before the race outside of the gates before they let us in to line up so all I heard was a loud bang and I thought the powervaulve was sucked into the engine or a hole was in his piston

*so does that mean if you never change your piston on your 2t it woild judt lose compression over time but not seize? People always say 2t biles seize bcuz some1 didnt change the piston which makes no sense at all to me*

My ktm 200sx crankshaft main bearing went out. I’m getting it serviced right now. Should be getting it back in a few days.

The time my kx cut off 6 miles from home and had to push 3 miles about got age by hounded scared for my life lol I got extremely dehydrated wouldn’t crank bought spark plug though we blew it up and 3 months later we put spark plug in gas then it starts 😂

Nice video. I aspire to be like you and build bikes. Thanks for being detailed also, most people aren't as in detail as you

I just bought a 05 trx450r and I changed the oil as soon as I got it.... I should have known by the amount of metal shavings. First ride out fine, took it out of my truck started it and the rod bearing went. 100% seized. Looks like I’m doing a bottom end!!

2015 ttr 125 was with some buddy’s the other day she’s a rally bike so I didn’t really care about it I was going through the main trail on the governor pulled up piston broke through the casing bhys looked at me and we all died laughing

The 3rd piston you showed looked like it hydrolocked which would have bent the rod.

I want a dirt bike so much and i will get one soon, and im so worried about blowing the engine up when i start learning ;(

Do you recommend cleaning the air box and air boot as well? Maybe during a winter maintenance

You should do more parting out bike vids. Love those!

thanks for those tips dude cheers from new zealand

I heard you always drive it slow to warm it up first

my big end bearing blew up a couple of days ago had pieces of metal bouncing above the piston and then when between the piston and cilinderwall, pretty fucked up

Your right bro, waiting eagerly for those build vids to come!! But hey, I have the same thing, I also build bikes and fix them, like now I have a BMW F60GS. The cam chain tensioner collapsed, causing the intake cam to skip a tooth, and the piston did not play nice with the intake valves, and the cam chain guides also broke into pieces. Now, everything is delivered except one intake valve, as BMW South Africa had only one in stock. Now, to my dismay, everything is laying on the bench, itching to be re-assembled, but I cannot do anything for now. You can check out my site over at www.accustoms.co.za click on the gallery link. Not a very impressive site, but hey, I am trying. Great stuff and keep the vids coming!!! You can bombard us with vids, nobody will complain!

Thanks this helped a lot 💙

Can you do a video on replacing timing chains?

I change my oil every 3 to 4 rides never had a problem besides a intake valve was out of spec an I replaced it no problem ever sense I use Amszoil an I use liquid chill by Mishimoto

Wow this is great. Nobody talkin about this. Can you please post a video about white engines overheat? Plus any videos about what people are doing that makes their engines blow up? Thanks a lot man!

My uncles friend red line it and blew it up it is a tri Z 250 3-wheeler

Four strokes go longer but if they blow up you got a big problem

My only reason why I prefer 4T over 2T because of people saying that 2T needs a rebuild earlier than a 4T would need it,however a 4T engine costs a lot more to rebuild!

I need a friend that's smart like you lol I watch your videos to learn about engines and mechanics I bought a non running 2000 r6 and got it running but I'm not good with tunning carbs and I know you can do a good check up on it if I knew you

hey could you boost your mic next time. Your voice is kinda low in all your videos. Love your videos don't get me wrong, I find them very helpfull

My 85 two stroke rod baring went out

Are you really from Finland? And you make great videos, helps me alot with my dirtbikes! Greetings from Finland!! =D

Mostly take care of ur bike change ur oil once and a while dont rev it all the time especially because race dirtbikes rev at really high rpms and it gets so hot that the engine gives its life away

Great video as usual! 💯

Great video. I'd like to see a video on low compression and things that cause it. My klx300 has sudden low compression when kicking over although runs just fine.

Fabulous operators 😀🍻

Do a video on why 2 strokes backfire

Well broken connecting rod is commonly causes by going too high into rpms

I'm looking to buy a dirtbike but I don't want to rebuild my engine as I don't know how to. What would happen if I don't rebuild it?

Another great video. Thanks amigo.

Setting a 2 stroke idle!

Cool video Cameron! On 2-stroke 125s I have had the circlips fail twice! Both time resulted in pretty horrible damage to the top end, destroying the cylinders. I hear it is a common problem because even with quality brands like Weisco or OEM, the circlips are cheap pieces of aluminum. Thoughts?

Thanks for sharing this information

Great channel very helpfully I have a question I have Honda cr80 2002 and my water pump seal went and I changed them and the bearing and 1month later it went again why is this happening thanks

Could it be a goo..d idea to change out the valve springs before they become too weak to close the valves fast enough to keep the piston from eating them like your own engine did and the piston with a valve smashed into it .??? .. And a good way to stop those cam cha ins from ventilating .the bottom end is to change them out before they c$$$ caching change you out ..that every year to be safe you gotta do ..like Indy cars that have to be done every race ....you see kiddies when you burn your candle at both ends you get a bright light .but for a very short time ....see you at the parts counter ..

ive had a valve snapped blew a hole through the piston fixed that then it blew up again a week later still not fixed that was about 2 years ago reason it blew up was my friend riding it through a big ass puddle un hydro locking the bike bent the rod lmao

My 2006 wr250f has 14000 kms on it who wants to start a bid when she will blow .. burns no oil and valves are always in spec

Learnin jettin

so my engine blew like last week, they way it happened was strange and i don't really know how. i have found out that the ignition plug was too long and the piston hit the tip of the plug which punched a hole in the piston. i wonder how this happened and how much damage there is to the engine. i was going to order a new sylinder with a cranck shaft anyways but if more of the engine is broken i'll just buy a whole new engine

Hello ,Can you make a video of how to mix 2 stroke gas. I'm really new on them and other vdo on youtube right now is kinda confusing with the ratio for each brand,bike.

Awesozme content as always? Whatsup with the cr 250 engine build ?

Thanks bro for the good information

Because it isn't a Yamaha.. Yamaha has the longest lasting top ends and cranks period . I didn't see any yamy parts lol

Bought my first quad last night went out this morning noticed sum oil on the case thought it was minor decided to take it out I’m riding along the road and I hear a scratch crack and a pop went to kick it over and it was stuck walked it home 3km to find out the engine had zero oil in it cuz it all leaked out

So the way I blow up my engine is I bought a new header for it an I wanted to ride because I haven’t been able to so I was riding a dr49 Baja on the road an I first broke a rocker arm fixed that then the valve blew off an blew a hole in my piston bought a new top end just got to put it in idk y it happened

Cameron really likes his work guy, I invite him to come to Brazil and stay at my house and ride in our training center, it will be an honor \m/

Do a video on why over reving the bike will destroy the engine.

I blew my motor up last year cause my powervalve got stuck and the piston had too much play it costed my father 365 overall Zylinder piston and so on I got a question how can you get you’re two stroke running as cool as possible