Tecate crankshaft play (please help)

[denn]

I pulled my tecate cylinder today due to a broken powervalve arm mechanism. It has a hot rods connecting rod in it which I tought had a bit of excess play. As I was rocking it side to side i noticed the CRANKSHAFT had side to side play as well. I have never seen a crankshaft move side to side in a case before. I am BRAND NEW to TECATES and don't know if there is supposed to be any or what could cause this. I could really use some help. I haven't had much luck on the site lately with answers but I am hoping some tecate people will chime in on this.

Thanks Denn

[fabiodriven]

A little bit of lateral movement in the rod is a pretty normal thing but if the rod "rocks" from side to side, you have an issue. The crank should not be moving from side to side. It's impossible to give you a positive answer just from a description, but it doesn't sound good.

[Dirtcrasher]

I'd have to see a Tecate engine apart.

Wouldn't just the primary gear nut itself prevent any lareral movement??

Or do you mean the connecting rod has some side to side movement which is fine........

[Vootie]

a mm or so of lateral movement is fine and normal for the con rod, but up and down and rocking movement is not. If the whole crank is rocking back and forth, that is definately not good. My guess would be that the crank bearings are toast. Side to side movement of the crank itself I don't think would be possible?

[tecat-z]

The main bearings are shot. Lateral movement of the crank is held in check by the bite it has on the two installed main bearings. Which are installed at a predetermined width set at the factory. The max width of the crank wheel bearing area is slightly less than total inside bearing width. This is inside the crankcase. I hope this makes sense. Side to side crank play is allowed when the balls are loose in the races. This is why when having a crank rebuilt, it's very important to set the depth of crank wheels on pin exactly to spec. It creates many issues that many people don't realize. Nearly all 2stroke engines are designed this way. Well, all of the ones i've built anyhow......

[denn]

Thank you for all the replys, I thought along the same line. I am really familiar with 2 strokes engines and have never seen one have a crankshaft have side to side movement. I have been limited to tri-zs for the past 20 years. It was just the amount of play that had me wonder. Its like a
1/8" of movement from side to side. The bearing would have to be half exploded to allow that which is what made me wonder if tecates were some exception. I am going to say that I have to take it apart and see whats up. Although I wonder if when they installed the hot rods connecting rod they didn't screw something up. I cant see the crank being pressed in wrong cause wouldn't that screw up the connecting rod side play? That would make it to tight if they pressed them in to far. I hope that the taper on the crankshaft isnt messed up and allowing the crank to shift. Anyway i can play guessing games all day, I guess its time to pull the motor. Thanks agian for all the help. I'll keep you posted.

Denn

[denn]

Well I think I have a kx bottom end in here. I removed it(which was a snap) and the engine numbers start with KX250. It has a PVL ignition in it. I guess I'm going to do a full winter resto on it. I don't want to go to far without a manual. Anyone here know a good manual to use and where to pick one up?

Thanks Denn

[dcreel]

I'm pretty sure all the Tecate engine numbers start with kx250.

Here is a downloadable manual

http://www.oscarmayer.net/atc/manuals/kawasaki/1986_KAWASAKI_TECATE_SUPPLEMENT.pdf

[cr480r]

I'd have to see a Tecate engine apart.

Wouldn't just the primary gear nut itself prevent any lareral movement??

Or do you mean the connecting rod has some side to side movement which is fine........

no primary nut on these bad boys... just a clip... my guess is bad bearings or bearings floating in the cases.. not good

[nd4speed]

usually if you can grab the flywheel and the crank moves up or down or in or out, you have a problem

All the motors start with KX and none start with KXT cause they are all the same cases.

[denn]

Thats exactly what it is. When I removed the flywheel cover I was able to push in and pull out on the flywheel. I going to say its the bearings are royaly #ucked or something along those lines. The primary gear snap ring sounds like a nice thought but the crank should still be tight once the cases are pressed together since the primary gear collar rides on the outer surface of the bearing, it shouldn't have no effect on the crank tolerance. Right now I am waiting for a manual I ordered. I have the 1986 tecate service manual supplement but it sucks and is not very detailed. Everything important says refer to base manual. So I found one on for a 1986 KX250 on ebay and I scooped it up. Ill have it torn down anyway by the weekend. Ill take some pics of the mess and post them up.

Denn

[nd4speed]

I had a 84 KX250 motor that lost third gear. When I took apart the motor, the crank was super sloppy like that. It ran great though.

[Tecate250]

Wow! Am I ever glad i come here. I removed my mag cover to water proof the gasket for deep water and noticed the same thing. Ran great. I was also noticeing last time i re did my crank it didnt fit in the cases right. The crank was offset a bit. I was told to hammer it over with a rubber mallet.