Burned up rod bearings... Q&A

[93cr250]

To make a long story short. I was doing a semi-long up hill and the throttle stuck open in second gear. The hill was still alittle icy and the bike got out from underneith me, the bike flew about 10 feet up the hill and fell upside downish. The throttle was still wide open screaming away. By the time I got up to it (about 30-60 seconds) the motor was starting to slow down. I grab the kill and shut it off. When I got to the bottom of the hill the motor was frozen. I torn the top end off and the piston seemed fine... alittle baked oil but no scoring. The rod was very hard to move. So I split the cases and for sure the rod connection to the crank was toasted.

The main question is that there was some copper from the spacers on the sides of the rod that dug down into the cases leaving some heavy marks (1/16 to maybe 1/8") on the bottom area of the crankcase. Is this someting I should try to fix or get fixed before I install a new crank/rod/bearings ? I heard that this is a very important area or part of the motor beacause fuel/oil flows down there. And it should be clean and smothe.

Just sucks because the all the bearings and seals were replaced about a year ago. oh well had to change the clutch bearings and basket anyways.
Sorry the bike is a 93 cr250.

Thanks Brian

 

[David Trustrum]

I really wouldn’t worry about it. I mean I’d clean it up taking the burrs off it to avoid any more swarf coming off but at the bottom of the cases (as long as there isn’t a hole thru em or nothing) the gas flow isn’t going to be that critical. That part of the engine is just a pump & a fairly inefficient one at that.

If you were really worried you could fill the groove with some Devcon if you were cautious that it wasn’t going to dislodge. Safer just to leave it.

 

[tony91]

No worries man. I've got a 92 CR250 which had a pretty hairy low end melt down. My only prob was that a piece of the crank gashed the cases right were they met...not quite all the way thru....but just enough to make me worry about getting a good seal. I just draw filed the gash and haven't had a prob since. Also the cases were pretty scared up as well but no probs with that either. Hope this helps