Strip down questions

[savage sausage]

Ok so I'm having a go at my 1st ever bottom end strip down and I've got so far

Firstly how do I remove the woodruff key that's holding the crankshaft cog without damaging it

Secondly does the nut holding the flywheel weight & flywheel turn clockwise or anti clockwise

Then I suppose I will need a flywheel puller then can start undoing the case bolts
Any advice for a virgin stripper would be appreciated

Thanks

 

[stabak]

Remove the cogwheel and with a flat tipped screwdriver or smg slide out the key by hitting one side. It will pop out, be careful

Flywheel nut normal clockwise tightens.

Yes you'll need a puller for the flywheel and a holding wrench of some kind.
You can split the cases with no special tools but it's not the proper way

 

[dANbOT]

If you have never split a bike engine before, I suggest you get a case splitter, and a crank puller/installer. Tusk makes cheap ones that work well. It can be done without these tools, but I wouldn't recommend doing it this way for your first time.

Case bolts tend to be several different lengths, I always draw a pic of the bolt pattern on cardboard, and poke the bolts into the matching hole as you remove them.

Another trick I learned years ago, is to wrap the transmission assembly with Saran Wrap before removing it from the case.

Take lots of pictures, and make notes as you go!

 

[GGRider01]

Remove the cogwheel and with a flat tipped screwdriver or smg slide out the key by hitting one side. It will pop out, be careful

Flywheel nut normal clockwise tightens.

Yes you'll need a puller for the flywheel and a holding wrench of some kind.
You can split the cases with no special tools but it's not the proper way

What thread pitch is needed for the flywheel puller? Are they reverse thread like most?

As someone that operates on a tight budget I've always just put the bike in gear and whacked the wrench real good with a hammer to pull the flywheel with the puller. There are a lot of "I don't recommend this, but this is how I do it" things you can do to save money and that is probably in that category.

 

[stabak]

What thread pitch is needed for the flywheel puller? Are they reverse thread like most?

As someone that operates on a tight budget I've always just put the bike in gear and whacked the wrench real good with a hammer to pull the flywheel with the puller. There are a lot of "I don't recommend this, but this is how I do it" things you can do to save money and that is probably in that category.

M27x1mm like most yes left threaded

Know what you mean on the tight budget but again some of them are cheap as the puller and let you do stuff without any help. About a meter of tube levering the wrench comes handy too...

 

[jmdcr50]

Fly wheel pullers are cheap , I had bought one for a cr 250 and it fits yamaha and gasgas .Also if you have a harmonic balancer puller all you have to do is get longer bolts it works very good . when your ready to put the motor back together stack bearings on the flywheel crank side and slowly clamp together . I do this all the time never had a problem. hope that helps

 

[Zman]

I fully agree you will need a flywheel puller, but you may not need the case spitter / press. Obviously you do not want to use any metal objects to pry the cases apart from the seam but you may need to lightly tap them apart with a dead blow plastic or rubber hammer. I have split the cases on 5 different GG engines and never needed a puller to get the cases apart. All 5 went back together with minor pressure by hand. I am sure that it is necessary for some engines but you may want to try it by hand first.

 

[swazi_matt]

How do you know when it is time for big end replacement? I am on about 230hrs and about to put in my third top end (including original) but I am generally lugging around on single track trails hardly ever need 5 and 6th

 

[Zman]

Look and feel for any vertical play in the rod, excessive side clearance or if does not feel smooth. I still have the original rod in my 2000 XC300 with the 327 big bore kit and I ride it hard every chance I get. Mine is on its 4th piston as well (2 stock and 2 big bore).

If you are in the bottom end for another reason I suppose it may be a good idea to change it for peace of mind but otherwise I would ride it. I have had very good luck with Ryan Callies at Finish Line Engines. He does crank rebuilds for many of the shops in the area. He also does cylinder and head work. His prices are very fair, he is honest and he does great work. http://www.finishlineengines.com/

 

[Jakobi]

Hey Matt,

I did my 2010 at 260hrs. Everything checked out OK! but one thing to note. These year models they used the sealed main bearings. Mine had sweet FA grease left in them when I pulled the seals off.

You might get another 80hrs out of it though, but I would plan a preventative trip into the bottom end at some point.

Cheers

 

[Zman]

Agreed! Having sealed crank bearings would be a good reason to freshen the bottom end.