How do you tell, by rocking the rod back and forth in the direction of rotation.  If its notchy in any location, something is wrong.  If you can't feel any notchiness anywhere during a rotation AND there's no up down play, then its good.

Well, I was able to get the rod to lock up in a certain spot- i think that would qualify as notchiness.   Also it seems like there's a little bit of up/down play, but it might just be the side to side play.  

So it looks like I'll be getting a new crank.  Couple questions
A.  Anyone have any experience with wiseco cranks?
B.  How do I get the flywheel off?  All the pullers are for 03 and up.

Thanks!

I have used the HotRods crank, and it worked well.  There differences between the 01 and 03 and newer cranks, so educate yourself and ask questions of your supplier.

I believe the YZ250F puller should work since the '01 is a kickstart only.

Ok, got the flywheel off, cases split and crank out tonight. Looks like one of the transmission bearings needs to be replaced.  The rest are smooth.  Did not see any metal shavings on the flywheel, just some on the bottom of the crankcases.  All the bearing cages were intact.

1. How do I get the bad transmission bearing out?  It's the one in the middle of the picture, and I don't have access from the other side.


2. Should I replace the main bearings anyway?

3. I'm thinking of buying a rod kit, is that a good idea?

Thanks!!!

Metal shavings should be tested with a magnet to see if they are steel or aluminum.  Steel means bearing cage or other.  You know to check the magnets on the flywheel for debris.  If the main bearings are tight, are not noisy, and roll free, there is no reason to replace them.

On the crank, It's better to replace the whole crank.  You didn't say anything  about the gear on the left end of the crank.  That gear will not be replaced if you just do a rod kit.  If you get a new crank, you get a new gear.  Its not like the Honda where you can replace it separately.  And once you pay to have the rod kit installed, you will have the same amount of money tied up in it.  Always repace the crank for that reason. Inspection on the gear will most likely show sharp pointed teeth if the gear is worn.  If its not worn, the teeth will look exactly like the teeth on the cam gears.

Edited by ronbuell, 12 May 2012 - 07:21 AM.

Ok, and no ideas on how to get that bearing out?

Most of the shavings stick to the magnet.  Especially the bigger pieces.

I found a new Pro X rod kit for about $80.  I think it will be about $70 to get it put in.  I found a used crank for $170, but the seller has a 100% money back guarantee it's good.  The best price I found on a new one is $260 on ronayers.com.  There is definitely some wear on the timing chain gear on the crank:
http://i1028.photobu...0f/DSCN5478.jpg
http://i1028.photobu...0f/DSCN5477.jpg
http://i1028.photobu...0f/DSCN5476.jpg

Edited by jamesm113, 12 May 2012 - 10:29 AM.

They make bearing pullers, looks like 2 hooks on hinge pointing out.

Hot Rods, Inc.
2751 Parkside Circle
Urbandale, IA 50322, USA
Ph: 515.402.8100
I talked with Steve Beaver at Hot Cams, same company, very helpful.  I have found NEW cranks for as little as $180... keep looking.   TT also sells parts on here in their store, not familiar with their pricing.

Your crank gear is definately worn, wouldn't want to loose the top end due to jumped time in 15 to 25 hours after all this work.  

You need to look at the black rubber sliders the chain is running on to see if there are deep grooves worn in those, and see if there are grooves cut out of the cases and cylinder where the cam chain has been whipping out of the sliders.  Replace if worn.

Test the cam chain by dropping it on a flat surface, then pick up one link and let the whole chain dangle.  If kinks remain in the chain, replace it also.  Since there has been metal in the bottom end, also flush out the oil tank in the frame, rinse out the lines and blow out,  AND disassemble and inspect the oil pump looking for grooves cut into the surfaces.  

Fun isn't it.

Ok I found the bearing puller at the local auto store, they called it a pilot bearing puller.

I won't be rebuilding this crank then.  The problem is I haven't found any aftermarket cranks for 01s and 02s WR/YZs (Wiseco, hot cams/hot rods, and pro x don't list any in their catalogs).  TT's price was $336 for the whole crank assembly.  So the options I've found so far are Used OEM and new from yamaha.  Or try to fit an 03 crank in there somehow.  None are very good options   

Black rubber sliders looked good.  No grooves or wear from the chain in the cases, cylinder or head.  Chain's good too, though for $20, I'm going to replace it anyway.

I'll flush everything out.  Very fun

Thanks again for your (and everyone else's) help!  It's very appreciated!

here you go.....

http://www.ebay.com/...r#ht_506wt_1270

That's a good deal.  Offer him 200 and see how he responds.

Hmmm, that's a good find.  But a new crank would be 5NL-11400-11-00, not 5NL-11400-10-00  Anyone know the difference?

the add says that 5NL-11400-10-00 is the old part number. maybe Yamaha updated the part and 11 is the new part #.

_{oops I read it wrong..}

_{New oem crankshaft assembly.}

_{old # is 5nl-11400-00-00.}

_{will fit models listed.}

_{01-02 yz250f & wr250f models only!}

_{(pcm location)}

Also, what's the best way to clean the engine?  I've been using zep engine degreaser + rags + an old toothbrush, but it's taking forever.  

I have a can of chem dip that I used for my street bike's carbs a while ago, does that work good for engine parts too?  My friends said gasoline would work well too, but I don't have an open container, was thinking of a 5 gal home depot bucket, but I'm not sure how long it would last before the gasoline would eat away at it.

jamesm113, on 13 May 2012 - 03:54 PM, said:

I use degreaser and a scrub brush for the outside of the engine cases, then I thouroughly clean everything with brake parts cleaner. Brake parts cleaner is the best way I have found for cleaning parts without a parts washer. It takes oil residue off easy. It works great for suspension too.

Looks like the oil pump has scarring:

http://i1028.photobu...0f/DSCN5479.jpg
http://i1028.photobu...0f/DSCN5480.jpg
http://i1028.photobu...0f/DSCN5481.jpg
http://i1028.photobu...0f/DSCN5482.jpg
http://i1028.photobu...0f/DSCN5483.jpg
http://i1028.photobu...0f/DSCN5485.jpg

Just ordered new parts from powersportsplus.com  Crank was $253 minus a 5% off promo code, so $240.  Best price I've seen for a new crank with the new part number.  

Also ordered a used oil pump (w/ warranty), tusk gasket kit, new OEM cam chain, new OEM main bearings, new OEM bearing to replace the bad one.

Man...you have had quite a go with this bike, and after only 4hrs of ride time on it!

that being said, it will be nice to know that the engine will be fresh when your done....this will give you peace of mind at least.
I wish you well and hope you have loads of fun with it when it's done....you will have certainly earned it.

Is there any way to determine exactly what caused the rod bearing to fail?  The PO said he always would run 89 octane in it instead of 91.  Of course he said he had no problems with it...

Usually lack of lubrication is the most common culprit in machinery failure.