Is my connecting rod a goner? CRF450

jtiger12
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Forest H Ill, MD, USA
Edited Date/Time 1/25/2012 10:16pm
Guys, would like your opinions on what to do about this. I recorded some videos to show what is up.

Connecting Rod


Piston and Wrist Pin


Crank


At the end of last season I found some small metal flakes in my oil, 2 rides before the end of the season. I drained the oil, replaced the filer, took off the valve cover and checked the valves. Found the right intake a little out of spec, so I re-shimmed for my last race, planning to do a full rebuild over the winter. My seats are getting re-cut and valves replaced right now. While i was inspecting for crank and bearing play last night, I found gouging in the wrist pin, and some wear in the small end of the connecting rod. The crank has about 70 hours on it, and there is really no play that I can find in the bearings, everything seems normal. The small end of the connecting rod has some scouring, and the bronzing is almost completely gone (or is that burnishing that is showing up from wear?). Note however, there really isn't and up and down play in the connecting rod small end at all. There is some titling movement (which is normal?) but the wrist pin in the rod feels solid vertically. Please take a look at the following videos and offer up your advice.

1: Does this rod's small end look safe to run?
2: Can the surface be polished?
3: What on the bike options are available without splitting the cases and pulling the motor?
4: Is it time for a new crank, just to be sure?

I was planning to keep this bike for another year, and get a 2012 next season. With the $600 I'm putting into new valves, piston, cylinder, etc.. would it be advisable to drop another 500 and replace the crank?

Jason
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jtiger12
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3/1/2011 8:36am
I had a 2 stroke, sold it because it was a super-vibrating, pogo stick of an underpowered turd.

given your opinion however, i think i will just replace the crank. At this point ~$500 is alot cheaper than a new KTM250sx.
toolie
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Simi Valley, CA, USA
3/1/2011 9:23am
Yes change the crank and the main bearings there should be NO up and down play on the fly wheel.
ether the main bearing is bad, the crank has worn out in the bearing or the bearing is spinning in the case.
jtiger12
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3/1/2011 10:41am Edited Date/Time 3/1/2011 10:41am
toolie wrote:
Yes change the crank and the main bearings there should be NO up and down play on the fly wheel. ether the main bearing is bad...
Yes change the crank and the main bearings there should be NO up and down play on the fly wheel.
ether the main bearing is bad, the crank has worn out in the bearing or the bearing is spinning in the case.
done deal.. thank toolie and dirthead1. I ordered all my parts via service honda, including balancer bearings, water pump bearings, gaskets, etc, and it was CHEAPER than buying the hodrods complete kit online. i figured I would go OEM. Everything would still be good, If it wouldn't have sucked the dirt down into the cylinder.
mxb2
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Bowie, MD, USA
3/1/2011 2:38pm
jtiger12 wrote:
I had a 2 stroke, sold it because it was a super-vibrating, pogo stick of an underpowered turd. given your opinion however, i think i will...
I had a 2 stroke, sold it because it was a super-vibrating, pogo stick of an underpowered turd.

given your opinion however, i think i will just replace the crank. At this point ~$500 is alot cheaper than a new KTM250sx.
LOL, guess he did nt read the post!

The Shop

3/4/2011 3:03am
I know I can start a war asking this but what brand oil are you using? What year 450 is it? Any idea of thw hours on the engine?
jtiger12
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3/5/2011 4:38am
I know I can start a war asking this but what brand oil are you using? What year 450 is it? Any idea of thw hours...
I know I can start a war asking this but what brand oil are you using? What year 450 is it? Any idea of thw hours on the engine?
Sure thing. I use amsoil full syn 10-40. 2007 with ~72 hours total, 24 hours on that wiseco.
jtiger12
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3/5/2011 5:42am
oh.. and my intervals were ridiculousy short. changed engine side every 2 rides, trans change every 4-6. Oil filter, every ride. The metal flakes (chrome from the wrist pin) showed up after I tried following the manual, and using longer intervals for oil and air filters (cause i got lazy)
jtiger12
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3/14/2011 5:16am Edited Date/Time 3/14/2011 5:17am
update to the thread over at thumpertalk, something just doesn't seem right with the crank retainer tabs

Thumpertalk Thread

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