Blown up 21 Crf250r

Edited Date/Time 6/16/2022 6:59pm
Anyone else know of any 250f Honda’s having the piston rod snapping and causing the motor to grenade?


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murph783
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10/20/2021 4:53am
How many hours, what kind of mods, what kind of oil? Everything breaks eventually so details matter
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soggy
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10/20/2021 6:14am
That crank got hot!

Something doesn’t add up in this story.
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ML512
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10/20/2021 6:15am
40 hours Honda oil changed ever ride no engine mods
What’s the oil pump rotors look like? Cam journals? Mostly curious if oiling system started to go. They’re sensitive if something gets run through them.
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The Shop

oceantrav
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10/20/2021 6:27am
40 hours Honda oil changed ever ride no engine mods
Why would you change the oil every ride?

Think the manual calls for changing it at like 15 hours.

My kid has a 21 crf250, no issues yet
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ML512
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10/20/2021 6:57am
What's the water pump gear look like?
10/20/2021 7:17am
Willie Manning did the tear down said everything as far as water pump and oil pump are in perfect condition. No sign of getting hot. Rod bearings and piston bearing spin as they should and I are in perfect condition. It snapped in the middle of the piston rod. As far as oil change every ride we are a little OCD.
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Boomslang
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10/20/2021 7:22am
Willie Manning did the tear down said everything as far as water pump and oil pump are in perfect condition. No sign of getting hot. Rod...
Willie Manning did the tear down said everything as far as water pump and oil pump are in perfect condition. No sign of getting hot. Rod bearings and piston bearing spin as they should and I are in perfect condition. It snapped in the middle of the piston rod. As far as oil change every ride we are a little OCD.
A question....did the motor grenade on a hard landing?
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murph783
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10/20/2021 8:41am
Hmm it coulda just been a shitty run of conrods
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fourfourone
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10/20/2021 8:45am
40 hours Honda oil changed ever ride no engine mods
oceantrav wrote:
Why would you change the oil every ride? Think the manual calls for changing it at like 15 hours. My kid has a 21 crf250, no...
Why would you change the oil every ride?

Think the manual calls for changing it at like 15 hours.

My kid has a 21 crf250, no issues yet
Most 250 guys never go 15 hours on an oil change,
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Boomslang
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10/20/2021 8:53am
murph783 wrote:
Hmm it coulda just been a shitty run of conrods
If Willy can't find anything to cause the rod to break then take it up with Honda.

A freak occurrence and Honda may help out.....if you are lucky.
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10/20/2021 9:02am
Tried Honda. They said no warranty on race bikes. Tried to say water in the gas caused it. We run t4 and occasional rec90. Plus exhaust side of the valves would be clean if water went through it. Clearly that’s not the case.
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Boomslang
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10/20/2021 9:15am
Damn, feel for you bud. Going to be a costly rebuild.
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murph783
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10/20/2021 9:20am
Yeah I’m not buying the water in fuel thing either. Shit luck man, hope you get it cleared up semi painlessly!
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Broseph
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10/20/2021 9:32am
soggy wrote:
That crank got hot!

Something doesn’t add up in this story.
They all look like that due to the manufacturing process. It’s either induction hardening of the journals or heating the web to press the pin in. If it got that hot inside the engine, it would look nasty from burnt oil.
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soggy
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10/20/2021 10:43am
soggy wrote:
That crank got hot!

Something doesn’t add up in this story.
Broseph wrote:
They all look like that due to the manufacturing process. It’s either induction hardening of the journals or heating the web to press the pin in...
They all look like that due to the manufacturing process. It’s either induction hardening of the journals or heating the web to press the pin in. If it got that hot inside the engine, it would look nasty from burnt oil.
Gotcha. So it did get hot at one point but not from running the bike🤣
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motoracer58
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10/20/2021 10:51am
What level was the bike riden/raced at? We use these engines in our hybrid quads for the younger racers. I had one rod fail on a stock practice engine at around 30 hours. All our engines get carillo rods now. If you were a faster paced rider with 40 hours I would call that beyond the limit for hours on a 250 engine before needing a rebuild.
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PNWRider
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10/20/2021 11:04am Edited Date/Time 10/20/2021 11:06am
No warranty on a race bike? Understandable.

Water in the gas? Honda must be taking lessons from Ford’s diesel truck warranty dept…

Water would only cause a rod issue if it was in enough quantity to hydraulic lock it…which would look a lot different.

Go tell the dealer/Honda that you’d like to see things from their point of view, but you can’t get your head that far up your ass.

With regard to oil, I change mine every other ride (about 2 hrs), but it’s also a 450 and I short-shift. Every ride on a 250f is understandable. 15 hrs? Crazy talk.
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10/20/2021 11:18am
What level was the bike riden/raced at? We use these engines in our hybrid quads for the younger racers. I had one rod fail on a...
What level was the bike riden/raced at? We use these engines in our hybrid quads for the younger racers. I had one rod fail on a stock practice engine at around 30 hours. All our engines get carillo rods now. If you were a faster paced rider with 40 hours I would call that beyond the limit for hours on a 250 engine before needing a rebuild.
Decent C rider. New crank at 40 hours seems a little excessive. We have friends with over 100 hours racing every weekend no issues.
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OFalk280
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10/20/2021 12:02pm
40 hours Honda oil changed ever ride no engine mods
oceantrav wrote:
Why would you change the oil every ride? Think the manual calls for changing it at like 15 hours. My kid has a 21 crf250, no...
Why would you change the oil every ride?

Think the manual calls for changing it at like 15 hours.

My kid has a 21 crf250, no issues yet
They also say to change the piston at 15 hours along with that first (second after "break in" oil change) oil change. Let me know how that goes for you
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oceantrav
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10/20/2021 12:06pm
40 hours Honda oil changed ever ride no engine mods
oceantrav wrote:
Why would you change the oil every ride? Think the manual calls for changing it at like 15 hours. My kid has a 21 crf250, no...
Why would you change the oil every ride?

Think the manual calls for changing it at like 15 hours.

My kid has a 21 crf250, no issues yet
OFalk280 wrote:
They also say to change the piston at 15 hours along with that first (second after "break in" oil change) oil change. Let me know how...
They also say to change the piston at 15 hours along with that first (second after "break in" oil change) oil change. Let me know how that goes for you
Exactly, if your changing the oil prior to what the manual even calls for, then are you also changing the piston prior to 15 hours?

No one follows what the actual engineers recommend. They change the oil every hour, then piston at 100 lol
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OFalk280
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10/20/2021 12:14pm
oceantrav wrote:
Why would you change the oil every ride? Think the manual calls for changing it at like 15 hours. My kid has a 21 crf250, no...
Why would you change the oil every ride?

Think the manual calls for changing it at like 15 hours.

My kid has a 21 crf250, no issues yet
OFalk280 wrote:
They also say to change the piston at 15 hours along with that first (second after "break in" oil change) oil change. Let me know how...
They also say to change the piston at 15 hours along with that first (second after "break in" oil change) oil change. Let me know how that goes for you
oceantrav wrote:
Exactly, if your changing the oil prior to what the manual even calls for, then are you also changing the piston prior to 15 hours? No...
Exactly, if your changing the oil prior to what the manual even calls for, then are you also changing the piston prior to 15 hours?

No one follows what the actual engineers recommend. They change the oil every hour, then piston at 100 lol
I'm not so sure that the engineers actually write out the maintenance intervals...maybe a lawyer trying to sort out any and all ways in which they can deny a manufacturing flaw and just argue it to the owner no following the service intervals. Brother in law's 2020 CRF450R blew up with 3 hours on it during its second ride. Honda argued up and down that it was caused by using a K&N Oil Filter rather than a OEM Honda one after the first oil change. They just wanna cover their tail from spending more money
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Paw Paw 271
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10/20/2021 2:04pm
The piston sure shows a rich condition. A leaking fuel injector can cause excess compression and hydro lock failure.

PawPaw

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10/20/2021 5:19pm
as a high performance car engine builder for mainly LS engines. Shit happens on any and every high performance engine.
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UGOTBIT
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10/20/2021 5:44pm
The piston sure shows a rich condition. A leaking fuel injector can cause excess compression and hydro lock failure.

PawPaw

I would think if there was enough of any type of liquid in there to hydro lock it, everything would be washed clean
10/20/2021 6:10pm
The piston sure shows a rich condition. A leaking fuel injector can cause excess compression and hydro lock failure.

PawPaw

UGOTBIT wrote:
I would think if there was enough of any type of liquid in there to hydro lock it, everything would be washed clean
Hydro lock would definitely have cleaned at least the exhaust ports. I’m really just trying to see if anyone else has had a similar situation. I’m basically buying a entire motor minus the head to repair it.
jleews6
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10/20/2021 6:20pm
No it locked on the face of a single went otb at Orlando broken collarbone.
Hate to hear that. Maybe the rod had a defect or a crack from new. Just because parts are new doesn't mean they are good. Years ago I had 8 titanium intake valves brand new that were bad and they were $$$$.
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silver753
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10/20/2021 9:56pm
Most of the time a rod is broken with no piston or valve damage, it would be from the piston rocking back and forth and too much clearance between piston/cylinder. The piston rocks too far and locks in the cylinder, 14,000rpm's of downward force will tear the rod in half. Case closed.
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