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Yz250 bottom end- missing piece

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Attempting my first bottom end on my 07 yz250. Taken a few things off and when I tipped the case a small spacer fell out and I don't know where it came from. Couldn't seem to find it in manual. Anyone know. Also I forgot to take my front sprocket off. Any ideas to crack it off now that it's apart or do I need to put it back together. Cheers.  Sorry I'm learning hahah

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ok so I think I found it.  Let me know. Any ideas with sprocket would be great. dont really want to put it back together to get it off 

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I was just thinking the washer looks like part of the shift assembly.

The sprocket-I'm thinking, put the chain on it and put the other end of the chain in a vice. Use and impact or hit your wrench with a rubber mallet. 

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thats not a bad idea. ill give it a go. Sooooo when I was trying before I put the clutch basket back on and was holding it with clutch holder and it would lock up the sprocket. Some reason I cant lock it up from that side now... have I wrecked something?

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2 hours ago, Dan Soundy said:

thats not a bad idea. ill give it a go. Sooooo when I was trying before I put the clutch basket back on and was holding it with clutch holder and it would lock up the sprocket. Some reason I cant lock it up from that side now... have I wrecked something?

The gears might be in neutral or between gears. I highly doubt you've damaged anything.

If you can somehow how stop that sprocket from turning, just with some resistance or mass, then a $100 battery "rattle gun" (torque wrench) will spin the big nut off real easy. Get one if you don't already - great for the sprocket nut, and clutch hub and primary gear bolt.  Maybe just wrapping the chain around it and holding the chain will be enough to spin the sprocket nut off.

The part that fell out is part 5 in that diagram.

Other tips I can think of ...

Be careful to correctly re-install the washers on the shift and kick-starter shafts. They tend to drop out too.

When you replace the right side crank seal, don't do what I did and push the new seal in too far. Check out the service manual. Outer face is flush with the alum.

If you are only swapping the crank or main bearings or left side trans bearings, then you do not need to remove the gears from the right side half.  This saves a fair bit of time.

Be careful to spot all the metal dowel pieces. They're everywhere.

Do you have the right tools to split the case, pull the crank and clean the case joining surfaces?

 

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cheers guys. managed to get nut off by putting chain on and locking it up. yup I left gears in there and just replaced bearing and got crank in. having issues getting bearing into the other side tho. bearing is back in freezer, hopefuly get her next go

Edited by Dan Soundy

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cheers guys. managed to get nut off by putting chain on and locking it up. yup I left gears in there and just replaced bearing and got crank in. having issues getting bearing into the other side tho. bearing is back in freezer, hopefuly get her next go

Use a propane torch on case where bearing goes, it won't get too hot but the cast aluminum will expand and let you drop the frozen bearing in.....make sure it doesn't go too deep, needs to be a bit of room behind it.

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1 hour ago, hondaman331 said:

make sure it doesn't go too deep, needs to be a bit of room behind it.

First time I've heard that. I always drop them in. Ker-plunk. Frozen bearing (pre-oiled and no moisture on it). Heated alum with just a heat gun works.

With the bearing fully seated then the crank can be pulled all the way to bearing bore and you end up with the crank correctly centred in the case.

1 hour ago, Dan Soundy said:

having issues getting bearing into the other side tho. bearing is back in freezer, hopefuly get her next go

Put some gloves on. Hold it square/flat and drop it. Put some oil on the bearing before you freeze it. Acts as a little lube for the drop in.

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Put some gloves on. Hold it square/flat and drop it. Put some oil on the bearing before you freeze it. Acts as a little lube for the drop in.

Lots of times in manual it will show to be flush with recess or give an actual depth of bearing. Honda specifically can't be set too deep. Hell, even honda 4 strokes have a number. I've never had to replace a crank on a yz250, lots of pistons, never had or known of crank issues with them....or even hear about them wearing out.

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