Slight drag when spinning crankshaft

[queen of spodes]

How much drag should I expect to feel on a new motor?  There's a little resistance turning the crank over with the connecting rod (manually with my fingers).   Is this normal?

[sandblaster]

Assuming everything is assembled properly and you used assembly lube, about the only thing you should feel is the seals on the crank shaft journals.
It's very light.
Sometimes a light tap with a rubber mallet on the end of the crank shaft will lessen the slight drag you may be feeling.

[queen of spodes]

Crank spun freely till I put the water pump bolt on (and light torque not ratcheted down).  That's when the I felt the light drag.  I'll try bumping it with my rubber deadblow.

[sandblaster]

Ah... I guess I should have asked how far along the build was.
I was thinking that you only had the cases together and no other attachments.
The bump may not work and you may have to hunt for other binding area's one at a time.

[queen of spodes]

s**t.  Really don't want to have to pull the motor apart again. 

[queen of spodes]

Just went out and pulled the clutch cover & clutch assembly.   Loosened the right side crank nut.   Still have the same amount of drag on the crank when I spin it (maybe a teeny bit less, but not enough to count).   Next I loosened all the centercase bolts - same amount of drag.   

The input shaft spins freely, it's something with the crankshaft.    But what could it be exactly? 

[queen of spodes]

Hoping for some legit help.. this is my first solo engine splitting/reassembly project.   


What things could cause the crank to bind (the transmission input & output shafts are not bound and do not have any drag).  Could I have pressed a bearing too far or not far enough?   

[dave916]

Just went out and pulled the clutch cover & clutch assembly.   Loosened the right side crank nut.   Still have the same amount of drag on the crank when I spin it (maybe a teeny bit less, but not enough to count).   Next I loosened all the centercase bolts - same amount of drag.   

The input shaft spins freely, it's something with the crankshaft.    But what could it be exactly? 

I Would not go loosening centrecase nuts as u will damage the case sealer {probably need to take cases apart if u have }
looking back on your build thread look like u fitted the crank on the flwheel side first which is not way i would do it 
how did u fit{ method} the clutch side case on??   
Any tapping lightly hammer on case could cause u crank go out of true
A out of true will bind on the bearing at certain point more
IF it is  constain drag it could be the crank not centred on the bearings or side load on bearings due to crank bearing interferane fit
 

[queen of spodes]

What should the distance between crank half and case be on each side? Figure that'll be a good place to start.   

I'm mentally preparing for having to pull this engine apart again if need be.     Just want to ensure it's done right.  I didn't know to check for crank centered-ness when installing earlier, or to install it on the right side first. 

[dave916]

http://www.kxriders.com/forums/index.php/topic,11854.0.html


pretty much how i would do it except i would NOT put retainer [loctite}on the flywheel side inner race/ the crank need endfloat there heat expansion etc
You could u use pullers like u did on flywheel side/ But it always going to put a little strain on main bearing , but a good enough method as it does not risk any crank truning issues

{What should the distance between crank half and case be on each side? Figure that'll be a good place to start. }??
 ??
distance will vary between differant cranks {just centre it between cases]
be carefull hitting any crank end as without a JIG as you will untrue you crank /  a gentle tap on clutch side should be all thats needed if you fit that side first

your main concern would be not puting   your crank out of true

[don46]

Did you press it together? If so I would expect it to have a slight drag, kawie has a fork device if your going to press to ensure you do not press it out of true. If you have the fork device I would install it and tap the crank on the clutch side, that should center it and take the load off the bearings. I would also run a dial on the ends to make sure it is true. I use the hear/cold method, no pressing and everything fits nicely

[queen of spodes]

I'll get a feeler gauge on either side of the crank halves tonight and see what I come up with.   The crank was rebuilt by RB Designs using NOS OEM bearings & con rod.   

Here are a couple pics from when I put the crank in the cases.  Sounds like you normally install it in the clutch side first then the ignition side second. 

IF I have to pull the cases apart again, will I need to get new main bearings or just the seals?  I used the freezer & heat method for installing the first side.  

[dave916]

I'll get a feeler gauge on either side of the crank halves tonight and see what I come up with.   The crank was rebuilt by RB Designs using NOS OEM bearings & con rod.   

Here are a couple pics from when I put the crank in the cases.  Sounds like you normally install it in the clutch side first then the ignition side second. 

IF I have to pull the cases apart again, will I need to get new main bearings or just the seals?  I used the freezer & heat method for installing the first side.  

Did the clutch  side case go together easy?

IF it did i would not go pullling it apart again
even using the freezer /heat method requires a bit of practice{speed}
To centre the crank from flywheel side u could LIGHTLY wedge something between crank webs to keep it true
IF u mount the motor steady and check the crank ends with a dial gauge { even checking the outer of crank webs all round {caliper] woul give u a good idea if its stiil true

[queen of spodes]

The clutch side went in okay, didn't have to fuss with it at all. 

Got measurements between the case & crank wheel.   Clutch side: .046 in.   Ignition side .034 in. 

Ignition side clearance: .034 in.


Clutch side clearance: .046 in.

[queen of spodes]

Setting aside the dial wheel for a minute, assuming this crank is still in true -- how do I get it centered?  

Edit to add some links for looking at later:
http://www.thumpertalk.com/topic/1005042-crank-centering-question-95-200-h1/

http://www.thumpertalk.com/topic/806746-centering-the-crank-94-cr125-after-rebuild-slight-binding/