2001 xc250 crank nut won't budge

[70455]

Needing to replace rhs crank seal.

Removed clutch and inner basket

Tried jamming rag, penny, thin aluminum between basket teeth and crank teeth. 1/2 drive with breaker bar. Fail. Gears chew up all. Ccw direction rotation.


Using electric impact with 30mm socket ccw fail.

What am i missing? How do i lockup the crank so i can apply big torque?

[GMP]

STOP! Its a reverse thread! A good 1/2" impact tool should get it off without much trouble.

[djroggen]

If at first you don't succeed just get a bigger hammer?!?

GMP is spot on. I have learned a good rule of thumb for any bolt that is a pain, if it doesn't come out with a reasonable amount of force and it is in an engine, I try it reverse thread. Then I move to a bit of heat if someone red LocTited it.

[jostby]

Originally Posted by 70455

Needing to replace rhs crank seal.

Removed clutch and inner basket

Tried jamming rag, penny, thin aluminum between basket teeth and crank teeth. 1/2 drive with breaker bar. Fail. Gears chew up all. Ccw direction rotation.


Using electric impact with 30mm socket ccw fail.

What am i missing? How do i lockup the crank so i can apply big torque?

previous owner may have used red loctite, good stuff If you are going ccw as you stated then instead of an electric impact you may need to use an air impact to get it loose. They are much better at breaking things loose.

[GMP]

Yes they are, but if it breaks loose going CCW its because the nut and/or crank threads have stripped. A good air impact tool, especially now as you have probably added a few Nm to it.

[70455]

CW hf impact pulled it off. Thanks a million!

Do i use puller to get ignition inertia ring off crank?

Crank has about 0.5mm play up and down. Would this have caused seal to wear? What's the max vertical play?

Are the crank bearings unique to this bike or are they borrowed from big 3?

[GMP]

Flywheel puller, common to all 2K-2, 2K-3 Kokusan flywheels used on modern 2strokes, easy to find.

The ignition side uses a two part roller bearing with more normal play than the ball bearing and is detectable even when new. The primary side retains the ball bearing and should not have detectable play. A true .5mm is a lot, and sound like its time for a lower end rebuild. Did the bike vibrate?

[70455]

Primary side has what looks like a 3" round disc between crank nut and seal. Do i use two jaw puller to get this off?

Some vibration present. Loose rivets on clutch basket caused noise when clutch collapsed.

I dont see bearings as available on gf website.

Are the bearings a shared part with cr250, or??

I recall someone posting the information below for sourcing seals and bearings from industrial supply chain:

" As fitted to my 02 EC300

ITEM BRAND PART No 1 x SMALL END BEARING INA KBK 18x22x22 1 x LHS CRANK BEARING SKF NJ206ECP - C3 1 x RHS CRANK BEARING SKF 63/28 - C3 1 x LHS CRANK SEAL KOK 20x35x6 -VITON 1 x RHS CRANK SEAL KOK 38x52x7 -VITON 1 x COUNTERSHAFT BEARING SKF 6305 -C3 1 x COUNTERSHAFT SEAL GENERIC 30x40x7
"
Has anybody sourced crank bearings from industrial suppliers?

[70455]

Image of disc.




<a href=http://s756.photobucket.com/albums/xx204/70455gto/?action=view&current=2012-11-15_06-51-45_419.jpg target=_blank><img src=http://i756.photobucket.com/albums/xx204/70455gto/2012-11-15_06-51-45_419.jpg border=0 alt=></a>

[GMP]

The disc is a primary crank weight to add flywheel effect. It should come off easy along with the gear with a simple puller. This can be replaced with a small spacer from the MC (motocross) model for faster reving if desired.

The lower end: rod kit is the same as a Honda CR250, easy to source. OEM is usually Vesrah. The crank bearings are easy to find at a bearing house. The seals are a common size as well, but Viton is less common stock from bearing suppliers. I get everything from a bearing shop (better grade bearings) and the seals from a dealer if not available.

Are you in the US? There is an excellent bearing supplier in NJ that used to supply the previous GG importer with bearings as well as many race teams.