Fixed it for you... we've all done it...

I usually use an air impact wrench... nut is right hand thread so normal counterclockwise rotation to loosen... I'd use a bigger pin like the actual piston pin and make sure both blocks are the same height.

thanks or the fix and advise just need a impct wrench and ill give it a go thanks

Yes, use a bigger solid bar through the rod eye but not a rough bar as don't want to damage the rod & block it so the crank bigend is about halfway up, so a good leverage point. I just use a socket & good handle. Not keen on air rattle guns when the big end is taking the strain, but just my personal preference. Might need an extension on the socket handle as it'll be 'tight'. Normal thread so standing behind the motor & pushing down on the handle.

hello finaly got the crank nut of couldnt get a impact wrench so used the long bar and wedged the crank with wood thanks for that advise then onto the engine screws nightmare again 3 of them rounded and the little one on top of the engine shoker anyway managed get them out today, tried tapping engine and pulling apart but didnt seem to want to go i didnt try too hard in case ive not took something of so heres a couple pics of were i am is there anything else needs come of or should they split here sorry if youve told me before but this is all new to me thanks

Hello pal and welcome along.
To split the cases correctly you need a puller set and some form of heat. Yambits in York sell them.
Seriously you should read the manual over and over until you understand what it is your doing and how the force your applying is acting on what.
I think you can get an awful lot of insight into the job from watching Joe Greshes youtube 360 strip and rebuild so you can see what's going on .
joe is a member here too, in fact you can see his bike on the forum opening page. It's the pic of the guy putting fuel in his bike.
knowledge is power .
at the end of it , i would say be careful and don't brake anything. Some parts are very difficult to find here in the UK.
Regards Ted.

Can someone post a link for that video ? I was unable to locate it. Thanks

Not a video, but there must be something here:
yamaha-enduros.com/index.php/forums/sear...te=all&childforums=1

My guess is that it's this one...

thanks for replys not had chance to get back on it yet hopefully weekend that videos is ace realy helpfull ended up buying another of ebay last weekend dont no why same condition maybee worse not picked up yet think im addicted

Take that nut off the countershaft before you start separating the cases!