First timer to the forum. I've probably got 50 hrs or so on a fresh top end and it looks like the cylinder base gasket has just blown again- oily residue ozzing down on the case on the right side of the motor. Bike runs fine - but I'm wondering if anyone else has experienced this happening on theirs. I'm just about to change the gasket out. Any suggestions or thoughts of why this might be happening? This same thing happened previously with 75 hrs or so on the top end. I changed out the gasket and didn't have any more issues until I redid the top end. Now it has happened again. Any thoughts? I'm getting tired of doing this mid rebuild.[img]i/expressions/face-icon-small-confused.gif[/img][img]i/expressions/face-icon-small-frown.gif[/img]

Thanks,
Mark

 

Welcome to the forum Dunerfool, I dont have a '86 250R but I have had experiences with blown base gasgets. I am asuming you retorqued the cylinder base bolts after putting a few hours on it. My CR500 and my sons WR250 both had problems with blowing base gasgets. They would both blow the in the thin transfer port area of the gasget. What I ended up doing on both of them was taking a center punch and slightly punching a spot about every 3/16 of a inch in the transfer port area. Approx 30 punches a side, mine leaked from either side. I did this to the cases and what it does is raise the area a little bit so the cases can get a good grip on the gasget material.

 

Are you sure its the base gasket? or just from the pipe. Take a can of startinf fluid and spary around the base of the cylinder while running. If it revs up at all theres a leak for sure. If you do end up replacing the gasket put some gasket cylicone on it.

 

I put aviation form a gasket on my base gaskets and it seems to be doing fine. You can get it at any Oreilly's or Autozone....Chris

 

Thanks for all the input everyone. My gaskets should be in tonite. I'll let you know how I fare. It will be cutting it close to getting it done before this weekend, so I may hold off until after Memorial Day. I guess as long as I don't run it WOT and lean it out with the leak I should be ok.

 

crazy thought, but....if you do really have 50hrs on the upper end, throw a set of rings at it while you are there........