Dirt bike grenades

busta_FATmoto
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busta_FATmoto
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BobPA
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BobPA 12/23/2016 4:40pm
12/23/2016 4:40pm
Yamaha's never blow up....
ML512
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ML512 12/23/2016 4:59pm
12/23/2016 4:59pm
I've taken apart more blown up two-strokes than four-strokes, so odd...
cameron96
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cameron96 12/23/2016 5:05pm
12/23/2016 5:05pm
200 hours on my 350. Leaks Coolant..
50 hours on the 150 and she let go, 530$ to rebuild.

Bummer

The Shop

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walent215
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walent215 12/23/2016 5:44pm
12/23/2016 5:44pm
BobPA wrote:
Yamaha's never blow up....
Lol..love it.we've had more 4 strokes since 2001 that I can't even count and have only broke one. It happened to be a full 250f race motor I bought used ....not even shocked in the least that it broke a valve spring as I didn't know the hours and ....lol....it's a 250f...4 strokes have been good to us....we ride and race the crap out of em too...
jbonemalone
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jbonemalone 12/23/2016 6:32pm
12/23/2016 6:32pm
I have been a technician for motorcycle atv and jet skis for twenty years.
The amount of dirt bike engines I've seen is mind boggling.
I promise that two or four stroke, the failure rate of poorly maintained bikes are pretty damn equal.
A properly maintained four stroke will push 100 hrs easy for a vet , woods ,or weekend warrior.
A two stroke in the same condition will go just as far.
However , when the four stroke determines it's time to shake and bake,you better have a good line of credit, while the two stroke can just about be done with what you find in your cushions.
They both have their pluses and minuses, but you better believe that the two stroke has the cost per smile box checked.
JWACK
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JWACK 12/23/2016 6:36pm
12/23/2016 6:36pm
JWACK wrote:
It'll buff out.
inthebadboycorner wrote:
Might take a while though!
Right! Best fill them elbows up with grease.!
JAFO92
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JAFO92 12/23/2016 7:03pm
12/23/2016 7:03pm

jbonemalone wrote: However , when the four stroke determines it's time to shake and bake,you better have a good line of credit, while the two stroke can just about be done with what you find in your cushions.



And this is exactly why the OEMs pushed to phase out the smokers and bring in the cash-cow tractors. Not much to be made on new units, so lets make money on parts when Johnny Weekend lets the valves get outta spec and the tractor shits the bed. After that, lets look at the decision making process: Johnny Weekend still owes 36 more months of revolving credit on his rolling hand grenade when it munches a valve so whats he gonna do? Break down and buy all them big buck parts, thats what cuz he's stuck with it.
holverson34
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holverson34 12/23/2016 7:07pm
12/23/2016 7:07pm
I just got a job in high school, went racing with my dad and little brother. Parents always paid for all my riding until that day i decided To tell my parents it was time to start paying my own way as we were signing up and give my dad some cash.
Practice starts, I make it 2 laps and my crf dropped a valve and my piston looked like that. Lol. Wish I could have taken back the part about paying for shit myself. Side note, bike started making noise on lap 2 of a 4 lap practice but I rode the rest of practice lol. Surprised it still ran after we tore into it in the pits lol
brash
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brash 12/23/2016 7:16pm
12/23/2016 7:16pm
I bought a 2010 YZ125 dirt cheap on the Aussie equivalent of Craigslist.

Thing started and ran fine, just wouldn't idle.

I used that as leverage to get this bike for nearly nothing, other than the idle this bike was brand new.

I thought it would be old fuel, bad plug or gummed up carb. Did all those things and still wouldn't idle for shit.

Pull the pipe off, shine a torch down there and all I could mutter was "sheeeeeeeeiiiiit"



Take the head off, haha way worse.



Because Im a cheapskate, I poured premix down the bottom end, sloshed it out and no piston came out, gave it a new piston/ring and gave the cylider a good polish and it's been running like a champ ever since Smile

busta_FATmoto
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busta_FATmoto 12/23/2016 8:18pm
12/23/2016 8:18pm
It was a couple years ago actually on my roommates old bike. I was hoping to see other people's best engine failures in a picture. He has since been converted to premix. That head was toast
BobPA
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BobPA 12/23/2016 8:55pm
12/23/2016 8:55pm
jbonemalone wrote:
I have been a technician for motorcycle atv and jet skis for twenty years. The amount of dirt bike engines I've seen is mind boggling. I...
I have been a technician for motorcycle atv and jet skis for twenty years.
The amount of dirt bike engines I've seen is mind boggling.
I promise that two or four stroke, the failure rate of poorly maintained bikes are pretty damn equal.
A properly maintained four stroke will push 100 hrs easy for a vet , woods ,or weekend warrior.
A two stroke in the same condition will go just as far.
However , when the four stroke determines it's time to shake and bake,you better have a good line of credit, while the two stroke can just about be done with what you find in your cushions.
They both have their pluses and minuses, but you better believe that the two stroke has the cost per smile box checked.
If you let a 125 go for 100 hours you will be able to kick it over with your pinky...
TheOriginalPancakee 12/23/2016 10:08pm
12/23/2016 10:08pm
220 hours on my Suzuki 250 a few years ago. Not one dime put into it. 150+ on my 2011 Honda 450 few years ago not one dime put into it. Going on 100+ hours on my 2014 CRF not one dime put into it Smile oil and air filter is all boys

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markit
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markit 12/24/2016 12:54am
12/24/2016 12:54am
TheOriginalPancakee wrote:
220 hours on my Suzuki 250 a few years ago. Not one dime put into it. 150+ on my 2011 Honda 450 few years ago not...
220 hours on my Suzuki 250 a few years ago. Not one dime put into it. 150+ on my 2011 Honda 450 few years ago not one dime put into it. Going on 100+ hours on my 2014 CRF not one dime put into it Smile oil and air filter is all boys
Where are u getting free oil and air filters?
FWYT
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FWYT 12/24/2016 1:01am
12/24/2016 1:01am
brash wrote:
I bought a 2010 YZ125 dirt cheap on the Aussie equivalent of Craigslist. Thing started and ran fine, just wouldn't idle. I used that as leverage...
I bought a 2010 YZ125 dirt cheap on the Aussie equivalent of Craigslist.

Thing started and ran fine, just wouldn't idle.

I used that as leverage to get this bike for nearly nothing, other than the idle this bike was brand new.

I thought it would be old fuel, bad plug or gummed up carb. Did all those things and still wouldn't idle for shit.

Pull the pipe off, shine a torch down there and all I could mutter was "sheeeeeeeeiiiiit"



Take the head off, haha way worse.



Because Im a cheapskate, I poured premix down the bottom end, sloshed it out and no piston came out, gave it a new piston/ring and gave the cylider a good polish and it's been running like a champ ever since Smile

Holy crap, that's amazing. It was actually able to run with that piston in there? Dang!!
theinternetkid 12/24/2016 6:18am
12/24/2016 6:18am
I don't think it's cheap to do any rebuild. Last year I rebuilt a neglected 2001 CR125 engine. I had to send the cylinder to millennium tech, then I bought a new top end, crankshaft, main bearings and replaced just about every bearing and seal throughout the transmission. The total parts bill was $850. This was basically a worst case scenario, but that's still a lot of money. I can't imagine the cost if I had to buy a more expensive brand's OEM parts or pay for labor.
mxracer12587 12/24/2016 6:26am
12/24/2016 6:26am
theinternetkid wrote:
I don't think it's cheap to do any rebuild. Last year I rebuilt a neglected 2001 CR125 engine. I had to send the cylinder to millennium...
I don't think it's cheap to do any rebuild. Last year I rebuilt a neglected 2001 CR125 engine. I had to send the cylinder to millennium tech, then I bought a new top end, crankshaft, main bearings and replaced just about every bearing and seal throughout the transmission. The total parts bill was $850. This was basically a worst case scenario, but that's still a lot of money. I can't imagine the cost if I had to buy a more expensive brand's OEM parts or pay for labor.
3 k on a 4 stroke to do what u did .
pete24
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pete24 12/24/2016 7:10am
12/24/2016 7:10am
crf 250 2014 47 hrs never did anything to it, never had too sold it for 1500 as is

mx836
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mx836 12/24/2016 8:16am
12/24/2016 8:16am
theinternetkid wrote:
I don't think it's cheap to do any rebuild. Last year I rebuilt a neglected 2001 CR125 engine. I had to send the cylinder to millennium...
I don't think it's cheap to do any rebuild. Last year I rebuilt a neglected 2001 CR125 engine. I had to send the cylinder to millennium tech, then I bought a new top end, crankshaft, main bearings and replaced just about every bearing and seal throughout the transmission. The total parts bill was $850. This was basically a worst case scenario, but that's still a lot of money. I can't imagine the cost if I had to buy a more expensive brand's OEM parts or pay for labor.
That's nothing. $850 wouldn't replace a 4 stroke top end if you dropped a valve.
BobPA
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BobPA 12/24/2016 8:27am
12/24/2016 8:27am
theinternetkid wrote:
I don't think it's cheap to do any rebuild. Last year I rebuilt a neglected 2001 CR125 engine. I had to send the cylinder to millennium...
I don't think it's cheap to do any rebuild. Last year I rebuilt a neglected 2001 CR125 engine. I had to send the cylinder to millennium tech, then I bought a new top end, crankshaft, main bearings and replaced just about every bearing and seal throughout the transmission. The total parts bill was $850. This was basically a worst case scenario, but that's still a lot of money. I can't imagine the cost if I had to buy a more expensive brand's OEM parts or pay for labor.
mxracer12587 wrote:
3 k on a 4 stroke to do what u did .
Not even close, maybe if you paid someone to do all the work. 4 stroke cranks/piston/cylinder work are not that much more expensive then a 2 stroke..... In most cases they are very close in price. You are looking at about $500-600 (depending on what bike/parts you use) more if you replace the ENTIRE valve train.
r.sal923
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r.sal923 12/24/2016 8:33am
12/24/2016 8:33am
BobPA wrote:
Yamaha's never blow up....
walent215 wrote:
Lol..love it.we've had more 4 strokes since 2001 that I can't even count and have only broke one. It happened to be a full 250f race...
Lol..love it.we've had more 4 strokes since 2001 that I can't even count and have only broke one. It happened to be a full 250f race motor I bought used ....not even shocked in the least that it broke a valve spring as I didn't know the hours and ....lol....it's a 250f...4 strokes have been good to us....we ride and race the crap out of em too...
I have had more problems with the 3- 2 strokes I have owned then the 12- 4 strokes i have owned.
mxracer12587 12/24/2016 9:08am
12/24/2016 9:08am Edited Date/Time 12/24/2016 9:19am
theinternetkid wrote:
I don't think it's cheap to do any rebuild. Last year I rebuilt a neglected 2001 CR125 engine. I had to send the cylinder to millennium...
I don't think it's cheap to do any rebuild. Last year I rebuilt a neglected 2001 CR125 engine. I had to send the cylinder to millennium tech, then I bought a new top end, crankshaft, main bearings and replaced just about every bearing and seal throughout the transmission. The total parts bill was $850. This was basically a worst case scenario, but that's still a lot of money. I can't imagine the cost if I had to buy a more expensive brand's OEM parts or pay for labor.
mxracer12587 wrote:
3 k on a 4 stroke to do what u did .
BobPA wrote:
Not even close, maybe if you paid someone to do all the work. 4 stroke cranks/piston/cylinder work are not that much more expensive then a 2...
Not even close, maybe if you paid someone to do all the work. 4 stroke cranks/piston/cylinder work are not that much more expensive then a 2 stroke..... In most cases they are very close in price. You are looking at about $500-600 (depending on what bike/parts you use) more if you replace the ENTIRE valve train.
So you don't replace chain or tensioner with guides. I guess I might over do it . My thought if you have it off replace the things that will probably fail .
BobPA
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BobPA 12/24/2016 9:16am
12/24/2016 9:16am Edited Date/Time 12/24/2016 9:17am
Timing chain comes in the Vertex piston and gasket kit. Guides are $42....manual cam chain tensioners never fail...
mxracer12587 12/24/2016 9:28am
12/24/2016 9:28am Edited Date/Time 12/24/2016 9:33am
BobPA wrote:
Timing chain comes in the Vertex piston and gasket kit. Guides are $42....manual cam chain tensioners never fail...
Oh well not worth it.
Kenny Lingus
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Kenny Lingus 12/24/2016 9:49am
12/24/2016 9:49am
I'm not going to argue what costs more to fix/ride/race. A point that I would like to make is that I believe some of the belief that 4 strokes are less reliable comes from the fact that they have to be in near perfect working order to run where as the 2 strokes, as shown above, will continue to run as long as the crank spins. Even if it is only making 3hp. If I remember correctly, there was an article years ago that found CR125's lose something like 2-3hp after the ring(s) have only a few hours on them.

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