Post by 90GTVert on Feb 16, 2010 7:30:59 GMT -5
My Sunl 50cc GY6 leaked oil from the base gasket even with brand new gaskets. I think the actual solution might be to have the cylinder's base and the cases planed or milled to create true flat mating surfaces. That can be costly and time consuming, so I tried something else that worked for me.
For anyone else that may have issues with the base gasket leaking, here's what I did :
- Cleaned the cases and cylinder's mating surfaces very well with gasket scrapers, then a block sander and some 400 grit paper, then I used a medium 3M scotchbrite pad to go over them lightly, and then finished cleaning using a shop towel with some brake parts cleaner. Make sure you give the brake cleaner time to evaporate before continuing.
-Installed the knock pins/dowels in the cases.
-Applied a thin coating of Permatex Ultra Black RTV to the cases, making sure to keep the cam chain out of the way.
-I let the RTV set up for about 40 minutes. The instructions tell you to assemble immediately, but I've used this method on other things to get them to seal.
-Installed the cylinder and continued installation of the top end.
- Once the cam and rocker assembly was in, I torqued the 4 cylinder studs to 10ft-lbs and installed the 2 6mm bolts on the side fairly snug.
-I let that set overnight.
-The next morning I torqued the cylinder studs to 12, 13, 14, 14.5, and finally 15ft-lbs. I tightened the side bolts with a regular ratchet, since I don't have a wrench that goes lower than 10ft-lbs.
For anyone else that may have issues with the base gasket leaking, here's what I did :
- Cleaned the cases and cylinder's mating surfaces very well with gasket scrapers, then a block sander and some 400 grit paper, then I used a medium 3M scotchbrite pad to go over them lightly, and then finished cleaning using a shop towel with some brake parts cleaner. Make sure you give the brake cleaner time to evaporate before continuing.
-Installed the knock pins/dowels in the cases.
-Applied a thin coating of Permatex Ultra Black RTV to the cases, making sure to keep the cam chain out of the way.
-I let the RTV set up for about 40 minutes. The instructions tell you to assemble immediately, but I've used this method on other things to get them to seal.
-Installed the cylinder and continued installation of the top end.
- Once the cam and rocker assembly was in, I torqued the 4 cylinder studs to 10ft-lbs and installed the 2 6mm bolts on the side fairly snug.
-I let that set overnight.
-The next morning I torqued the cylinder studs to 12, 13, 14, 14.5, and finally 15ft-lbs. I tightened the side bolts with a regular ratchet, since I don't have a wrench that goes lower than 10ft-lbs.