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Full rebuild on yz 85 tips/help/ miccelanious questions

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So i recently came across a deal on craigslist and bought a 2004 yz 85 with a full fmf exaust, newer race rims and a hinson clutch system needing a piston and a crank bearing i purchased it, and have it torn down right now with the cases split. The wiseco rebuild kit came in today but im still waiting on a few replacment bolts for the cases. I was wondering if any of you had any tips on the rebuild in general, what to oil, what to check before i put the cases back together etc. and how to get the crank into the crank case bearing with out a press or a tool. I will post pics as i go along and i thank anybody in advance for any help/tips or tricks they can provide. Thanks IMG_3352.jpgIMG_3338.jpgIMG_3385.jpg

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Oil the cylinder and pretty much everything with some degree or assembly lube or premix in a pinch.

Make sure all the bearings are good and spin freely, with no noise or roughness.

You may need a rubber mallet or deadblow hammer to tap the crank in, they can put up a fight occasionally.

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14 minutes ago, MaybeMe said:

You may need a rubber mallet or deadblow hammer to tap the crank in, they can put up a fight occasionally.

If you hit the crank, you could knock the crank out of alignment.

Put the crank in a sealed plastic bag and leave it overnight in the freezer. Heat the bearings with a propane torch until they make drops of water sizzle. The crank will drop right in.

Note; you may need to center the crank, once the cases are back together.

Make sure you drop the crank straight in. If it gets cocked or crooked, you may have to heat the bearing again to get it apart and then start all over.

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33 minutes ago, Ron W said:

If you hit the crank, you could knock the crank out of alignment.

Put the crank in a sealed plastic bag and leave it overnight in the freezer. Heat the bearings with a propane torch until they make drops of water sizzle. The crank will drop right in.

Note; you may need to center the crank, once the cases are back together.

Make sure you drop the crank straight in. If it gets cocked or crooked, you may have to heat the bearing again to get it apart and then start all over.

Good to know, thanks. I don’t beat on it, usually a couple taps into submission ;)

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My dad said that today about putting the crankshaft into ice and heating the bearing up then putting it together but ive always heard lightly tap it with a mallet and put the case on then take the mallet and tap the case until they come together which one do yall recomend

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2 hours ago, medalheatpistons said:

My dad said that today about putting the crankshaft into ice and heating the bearing up then putting it together but ive always heard lightly tap it with a mallet and put the case on then take the mallet and tap the case until they come together which one do yall recomend

Tap until you can use 3 bolts just around the crank and evenly draw together.  Noise is normal :ride: load right side use two 4×4s or make box I've seen some do with 2×4 . Makes it much easier 

20170818_143518.jpg

Edited by Motox367

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3 hours ago, medalheatpistons said:

My dad said that today about putting the crankshaft into ice and heating the bearing up then putting it together but ive always heard lightly tap it with a mallet and put the case on then take the mallet and tap the case until they come together which one do yall recomend

 

Edited by Motox367
Double post for some reason

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Id recommend that you buy the crank installation tool.  They are not very expensive and you can find them online for approx $75

id suggest getting it for the following reasons:

1) It makes installing the crank painless.  It will let you assemble the case halves in minutes with no concern over knocking the crank out of true.

2) If you use the three bolt method for drawing the case halves together you end up putting a bind on the crank and when you're together the crank shaft won't spin without hitting the end of the crank end with a hammer etc.

3) Heating up the bearings and cooling the crank will allow you to put the crank shaft and bearing in one half of the case, but doesn't help with the other half.  It doesn't work, Sorry.  I've done engine rebuilds for years and it just doesn't work like you think.  The materials start to equalize in temp faster than you can get things together.  

4) It's worth not having a head ache or damaging new parts.

I can only offer so much advice, but like I said you'd be money ahead and no head ache, plus the tool is universal and can be used on many different bikes.

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