KDXRIDER.NET

I just pulled the top end and realized that the con rod has side to side play. I guess I have to split the cases to replace the lower con rod bearing right?

Some side to side play is necessary and allowable. It is the up and down or radial play that is not acceptable and a indication that you need a new rod assembly. I'm not near a service manual right now but generally you can expect in the neigborhood of .018 to .028 inch of side to side movement so don't get too excited about spliting the cases until someone else fills you in on the KDX allowable side to side play.

It will have side play...'sposed too... just not any tilt play.
Do you have Eric Gorrs Performance Handbook?
If not... get it. It explains alot of the questions about your motor that no one else will address. It's AWESOME!
That's where I learned about the piston circlip position.

Sorry I didn't mention it is a 2002 KDX200 and I believe that it is "tilt play", not just sliding side to side on the shaft.

If need be, I am considering splitting the cases myself. I have a Kawasaki repair manual. I wonder if a Clymer manual would be better?

Also what would I expect a dealer to charge for this?

Check out the links page... go to Eric Gorrs site, He is better and cheaper than any dealer. I think he will even send you a crate...

A Clymers is just like the factory manual... I have found this out a couple of times with various vehicles.

Thanks for the info guys, I'll check out EG's website.

I had the crank seals in my bike changed last fall at a shop and they charged me $100 with the engine removed from the bike and topend off.

The most current KDX covered by a Clymer manual is for the 1988 model, in the 1983 - 1988 KDX200 manual. They don't make one for any newer KDX's.

God luck on the bottom end.

Moto, That sounds like a very reasonable price. Maybe I should have them look at everything while they're in there. I am going to contact EG to see what he charges.

Or maybe I'll attempt it myself. I have never split cases but maybe it's time I learned.

Any advice or warnings from anyone who has done it? I don't have any specialized tools.

I would suggest you get a case splitting tool, plus read up on eric gorr's site on lower end rebuilding.

I just read EG's "Crank checking tips" and it says " Grasp the connecting rod and try to pull it straight up and push it down. It is normal to feel some radial play because the rod bearing is a needle bearing. You shouldn't feel any up and down play. If you do, rebuild the crank." I am now off to measure the side clearance between the rod and thrust washers. Maybe I don't have to split anything. My fingers are crossed.

Call me stupid, but I am still not clear on this.

Referring to my previous post, Eric Gorrs website says that Radial play is OK, but up and down play is not OK.

According to the Kawi manual, radial play is up and down play.

My con rod has this kind of play: you can rock it to either side of 90 degrees. The 90 degrees is the relationship of the centerline of the con rod to the centerline of the crankshaft.

Is this normal? Isn't that axial play?

Maybe my "radial" term is wrong and I'm confused.

But I'm 100% sure that any up down play that you can feel in the connecting rod means it needs to be replaced. The side to side play between the thrust washer and the big end of the connecting rod is the one that always present even with a new connecting rod assembly.

Idaho, I know that there is supposed to be a gap between the big end of the con rod and the thrust washer, and there is not supposed to be any up and down play.

I know that the con rod should slide from side to side on the crank pin.

My question is when holding the con rod by the top, should it rock past 90 degrees side to side?

OK, after reading this a second time, surely you are not meaning that it rocks 90 degrees from clutch side to magneto side. Tell me I am reading it wrong. Please.

Jason,
My con rod has this kind of play: you can rock it to either side of 90 degrees. The 90 degrees is the relationship of the centerline of the con rod to the centerline of the crankshaft
[/quote]


not "you can rock it 90 degrees to either side"

OK, thank goodness.

Somebody PLEEEEASE draw a picture!!

IC wrote:Some side to side play is necessary and allowable. It is the up and down or radial play that is not acceptable...

Can't get much more clear than that.

Think of what the radius is. From the centerline of the rod journal (not to be confused with the centerline of the crank), a radius measurment is going to be from the center out to the bearing surface. That is the circular part (thus the term 'radius') measured in two dimensions. If the measurement along that radius changes, that is radial play.

IC's use of the term 'radial' is correct.

If 'side to side' is said to be 'radial play' and thus OK, of what proscribed circle is the term 'radius' a description?

Indeed, from:
http://www.100megsfree4.com/dictionary/car-dicr.htm

we read:

radial play:
A bearing clearance in the radial direction.


Now...doesn't that explain it all perfectly?

I drew a picture...as soon as some kind mod 'splains to me why I can't post it, I'll get back to 'ya.

**edit**

I had a bad cookie policy...'Accept only KNOWN good cookies!' din't work!




Oh...those are supposed to be circles...my use of the ellipsis tool kind'a says otherwise...but take my word for it.

A proactive intercept (is that a Cyclic Redundancy Check?)....please no smarty remarks about 'back and forth' could relate to 'left and right' in the 2-dimensional drarwing. It's still a radial measurement!

CC, I agree that you and IC are correct. What I want to know is how much axial play if any is acceptable.