Excuse me sir, you have some puke on your shirt

NATEP231
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NATEP231
Edited Date/Time 8/27/2015 5:02pm


I was bitten by the four stroke big once again.
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hillbilly
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hillbilly 8/26/2015 8:49am
8/26/2015 8:49am
There is a reason that happened,not a common failure at all.

What is the background? Was it repaired from a failure before?
seth505
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seth505 8/26/2015 9:07am
8/26/2015 9:07am
h&m_cycle
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h&m_cycle 8/26/2015 9:09am
8/26/2015 9:09am
That truly is a mess... $
Uncle Tony
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Uncle Tony 8/26/2015 9:09am
8/26/2015 9:09am
Maybe you should, nah forget it

The Shop

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NATEP231
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NATEP231 8/26/2015 9:12am
8/26/2015 9:12am
This was a stock unopened motor. I had no warning at all it made 2 weird clicking sounds (similar to the honda flame out sound) and just shut off. The oil still looks brand new with maybe 2 hours of run time on oil, piston still looks good too. Luckily it was on a straight away but the parts bill is still gross
pete24
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pete24 8/26/2015 9:13am
8/26/2015 9:13am
heres one its a 14 crf 250 had a piston at 40 hrs, this is 58 hrs i think the rod broke, if someone has a different theroy lets here it





KTMShane699
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KTMShane699 8/26/2015 9:14am
8/26/2015 9:14am
How many hours on the motor itself? Have you had it since it was new? I'm going to agree with Hillbilly (who I hope is still drinking!) on this one. It's not a common failure.

Shane
Uncle Tony
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Uncle Tony 8/26/2015 9:16am
8/26/2015 9:16am
I know Hondas don't like new high compression Pistons on cranks with time on them
NATEP231
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NATEP231 8/26/2015 9:38am
8/26/2015 9:38am
She had close to 50 to 60 hours. Stock everything. I bought from a middle to late 50 year old he had it for less then a year. I would say it had 15-20 on it when I got it. I'm at the age now (30) where over revs and panic revs aren't nearly as common as they use to be
GeorgiePorgie 8/26/2015 10:52am
8/26/2015 10:52am Edited Date/Time 8/26/2015 10:54am
@pete24: 40 to 58 hours, at 40 you probably should of done the bottom as well. Compression gets bumped back up when you do only the top end, too much for the old bottom end to take and then the rod just gets blown apart.

This happens to people when they slap a 144 athena kit on their 20-40 hour stock 125 and they don't put a new bottom end in it. The bike just grenades after a few hours. (hours if you're lucky) Now obviously going from stock to bore to larger bore bumps up the compression more than just doing a top end.

What's the manufacturers recomnedation for the bottom end service interval?
TXDirt
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TXDirt 8/26/2015 12:23pm
8/26/2015 12:23pm
you can buff that out.
newmann
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newmann 8/26/2015 12:29pm
8/26/2015 12:29pm
Didn't know Reed made his on line of rods...

Grenaded rod right there!

VET176
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VET176 8/26/2015 2:14pm
8/26/2015 2:14pm
TXDirt wrote:
you can buff that out.
Tongue Smile
Titan1
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Titan1 8/26/2015 2:19pm
8/26/2015 2:19pm
NATEP231 wrote:
[img]https://p.vitalmx.com/photos/forums/2015/08/26/102988/s1200_image.jpg[/img] I was bitten by the four stroke big once again.


I was bitten by the four stroke big once again.
Well would "just look at it"

https://youtu.be/EF8GhC-T_Mo
IceMan446
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IceMan446 8/26/2015 2:21pm
8/26/2015 2:21pm Edited Date/Time 8/26/2015 2:22pm
...
peelout
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peelout 8/26/2015 2:23pm
8/26/2015 2:23pm
GeorgiePorgie wrote:
@pete24: 40 to 58 hours, at 40 you probably should of done the bottom as well. Compression gets bumped back up when you do only the...
@pete24: 40 to 58 hours, at 40 you probably should of done the bottom as well. Compression gets bumped back up when you do only the top end, too much for the old bottom end to take and then the rod just gets blown apart.

This happens to people when they slap a 144 athena kit on their 20-40 hour stock 125 and they don't put a new bottom end in it. The bike just grenades after a few hours. (hours if you're lucky) Now obviously going from stock to bore to larger bore bumps up the compression more than just doing a top end.

What's the manufacturers recomnedation for the bottom end service interval?
40 to 58 hours, at 40 you probably should of done the bottom as well.


oh man, that's a cold day in hell when my 300xc can't make it past the 40 hour mark lol

i put 60 hours and 1400 miles on the motor in Mexico last April, brought it home and changed the oil, rode another 300 mile ride and then put it away for a while. checking my trip meter, i have over 2500 miles in just over a year and have only changed the oil a handful of times.

hate to be the beater of the dead horse here, lol
overthebars39 8/26/2015 2:26pm
8/26/2015 2:26pm
I never had issues with my 450 but i've seen some bad things on 4 strokes that it got me scared to buy another one.
Question
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Question 8/26/2015 3:45pm
8/26/2015 3:45pm Edited Date/Time 8/26/2015 3:48pm
I am not a 4 stroke specialist but it is quite common in my area, plenty of grenaded bike to buy for parts.

Pit Row

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4stroke4DWIN
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4stroke4DWIN 8/26/2015 4:08pm
8/26/2015 4:08pm Edited Date/Time 8/26/2015 4:08pm
Edit*
4stroke4DWIN
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4stroke4DWIN 8/26/2015 4:14pm
8/26/2015 4:14pm
Here's a few pics to make the OP feel better lol, it happens. First rebuild on my then new 2012 KX250f "hot rods crank and forged piston" 2 hrs max and shit the bed. Been sitting since. I won't spend a dime on it EVER!



h&m_cycle
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h&m_cycle 8/26/2015 4:27pm
8/26/2015 4:27pm Edited Date/Time 8/26/2015 4:27pm
Those pictures are enough to make you sick...
tempura
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tempura 8/26/2015 4:37pm
8/26/2015 4:37pm
Four stroke magic
crf250pilot
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crf250pilot 8/26/2015 4:37pm
8/26/2015 4:37pm Edited Date/Time 8/26/2015 4:38pm
4stroke4DWIN wrote:
Here's a few pics to make the OP feel better lol, it happens. First rebuild on my then new 2012 KX250f "hot rods crank and forged...
Here's a few pics to make the OP feel better lol, it happens. First rebuild on my then new 2012 KX250f "hot rods crank and forged piston" 2 hrs max and shit the bed. Been sitting since. I won't spend a dime on it EVER!



Just little JB weld on it and sell it on CL.
scott_nz 8/26/2015 4:50pm
8/26/2015 4:50pm
4stroke4DWIN wrote:
Here's a few pics to make the OP feel better lol, it happens. First rebuild on my then new 2012 KX250f "hot rods crank and forged...
Here's a few pics to make the OP feel better lol, it happens. First rebuild on my then new 2012 KX250f "hot rods crank and forged piston" 2 hrs max and shit the bed. Been sitting since. I won't spend a dime on it EVER!



another reason not to use hotrods, would never put one of thier cranks in a bike,

Back to the OP, have seen a few of 4 strokes do this over the years, but none with the sort of hours you are talking about,

being a 2014 it might be worth fixing, if it was 5 years old not at all,
newmann
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newmann 8/26/2015 4:52pm
8/26/2015 4:52pm
13,500 rpms is where the magic happens.Smile
DA498
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DA498 8/26/2015 5:31pm
8/26/2015 5:31pm
This is the time Im glad to be old, slow and short shift!
pete24
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pete24 8/26/2015 5:37pm
8/26/2015 5:37pm
i sold the grenaded 14 crf for 1500 and was glad to get it
aFACEdismembered 8/26/2015 5:42pm
8/26/2015 5:42pm
newmann wrote:
13,500 rpms is where the magic happens.Smile
Double the rpm' s and more moving parts just to have it firing at the same rate as a 2 stroke.
cwtoyota
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cwtoyota 8/26/2015 5:44pm
8/26/2015 5:44pm
You guys are really screwing with my mind right now! Are those all 250cc engines?

I just bought my first four stroke... It's a YZ450F.

This new four stroke has about 22 hours on it. I'm changing the oil every ride (about 2 hours) with Rotella T6 and have been replacing the oil filter every other oil change with OEM Yamaha filters.

I was expecting this 450F to last me about 100 hours on a piston. What kind of life should a typical intermediate motocross guy expect from a 450F? Piston life? Valves? Crank?


I have had exactly zero issues with my 2008 and 2011 YZ125s. I basically ride them on the throttle stop.
I swap in a new piston & pin at 13 to 15 hours. Every other piston gets a small end bearing. The cranks are good for 80 - 100 hours. I check for bearing play every time I do the top end. I run 32:1 premix with a 50/50 mix of Trick 114 Leaded and Ethanol Free 92 octane pump.

125 clutches last a year of racing/riding (about 55 - 65 hours on the meter per year).
jeffro503
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jeffro503 8/26/2015 6:27pm
8/26/2015 6:27pm
4stroke4DWIN wrote:
Here's a few pics to make the OP feel better lol, it happens. First rebuild on my then new 2012 KX250f "hot rods crank and forged...
Here's a few pics to make the OP feel better lol, it happens. First rebuild on my then new 2012 KX250f "hot rods crank and forged piston" 2 hrs max and shit the bed. Been sitting since. I won't spend a dime on it EVER!



Damn brother! That sucker blew right out the bottom on that thing. I'm a 2 stroke advocate , but that stuff can happen to those too! I consider myself lucky ( knock on wood ) that I haven't had a bottom end go out on me as of yet. I have had to replace a few cylinders and top ends though. Gawd these pics give me a stomach ache.

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