CRF250r name this part

[norid]

I have a 2005 CRF250r that died on me a couple weekends ago.  The first symptom was low power climbing when at about 1/2 throttle.  I was having to slip the clutch on hills I normally just ride up.  The engine would rev higher but not under load.  Finally it got so bad I could not longer make forward progress.  I pushed the bike back to the truck and took it home.  I checked compression, cleaned the carburetor and checked for spark.  Everything looked OK although I wasn't totally sure the spark was hot enough to arc under the higher pressure in the cylinder during the compression stroke.  I also checked the timing to make sure it hadn't jumped a tooth.  Valves were in spec too!

 

I checked the coil and got a slightly higher than spec resistance on one side (should be 0.07 to 0.1 ohms and I read 0.3 to 0.4).  I decided to buy a new coil.  The new coil came and I measured its resistance and unfortunately it was the same as the old one.  Nevertheless I tried the new coil but no luck. 

 

Next I pulled the stator side cover and discovered lots of fine metal dust around the pickup sensor and also noticed this mystery part.  So, two questions:

 

1) would this metal dust be enough to cause a weak spark due to grounding of the pickup sensor?

2) what is the mystery part and where did it come from?

 

Any help would be appreciated.  I'm really tearing my hair out.

[Mike in OK]

That looks like a ground up valve shim. Anybody else?

[mxchri5]

It very well could be a shim, I haven't seen one in detail for a while so I'm unsure.

[norid]

Mike, I had the same thought but I pulled out my box of valve shims and the diameter isn't right.  Also, not sure what the dot is in the middle but my valve shims do not have those dots either.

[SLO_Rider]

It looks like it could be a ground up valve shim, although that dot in the 4th picture says otherwise. My 2nd guess would be part of the oil relief valve located in the left crankcase cover.

 

Have you checked your valves to make sure the exhaust shims are still in place?

[Solidpitch]

p

[norid]

p

 

I'm not sure I'm tracking with you. 

 

SLO_Rider.  Yes I'm sure it is not a valve shim and I have checked the exhaust and intake and they are in proper condition.  I'm wondering if it could be part of a tool or something that got dropped down during a valve adjustment or something.  I've looked at every schematic in my manual and I can't find anything close.

 

Looks like I stumped the experts!

 

Jay

[norid]

It looks like it could be a ground up valve shim, although that dot in the 4th picture says otherwise. My 2nd guess would be part of the oil relief valve located in the left crankcase cover.

 

Have you checked your valves to make sure the exhaust shims are still in place?

 

Oh, and I did pull out the oil relief valve and inspect it.  Not that either.

[moto867]

Looks like the oil restrictor plug that goes in the end of the crank on the mag side. Look at the end of the crank and see what it looks like.

[moto867]

Cant tell if it used to have a hole in the middle

[MOTOMCFROG]

could it be the end of the stator pick up sensor has become detached somehow???

[AddictedToBling]

could it be the end of the stator pick up sensor has become detached somehow???

 

That's what I was thinking as well.

[MOTOMCFROG]

That's what I was thinking as well.

 

 

yep im convinced, makes sense with the weak spark and look at this pic............. the end is definitely rounded and the one of the original stator looks hollow.

[AddictedToBling]

yep im convinced, makes sense with the weak spark and look at this pic............. the end is definitely rounded and the one of the original stator looks hollow.

 

Nice work ?

[SLO_Rider]

Wow, that's the first time I've seen that happen.  Glad you got it figured out!

[moto867]

I thought of that to but if you look at his first pic it shows the pick up coil intact

[AddictedToBling]

I thought of that to but if you look at his first pic it shows the pick up coil intact

 

That could be just what part of it remained intact.

Edited June 13, 2014 by AddictedToBling

[TDW]

Oh, and I did pull out the oil relief valve and inspect it.  Not that either.

Im wondering if it isnt the head of a rivet that holds the reed valve together, if it is from the reed valve there may be more pieces loose and floating around soon.

[moto867]

I believe the reed is held with screws

[TDW]

Not the best pic but you can see both sides, has a screw in one side and a raised area approx the size of the part that was found on the other side.

Kinda hard to tell though.

 

 

http://www.ebay.com/itm/08-crf250-crf-250-reed-valve-/251404156271