Dear all
I have just bought a STS .28 engine for my monster truck. I would like to dissemble the engine for cleansing or porting works. Upon removal of the cylinder from the engine block, I found that there was no cir clip at the end of the piston pin facing to exhaust port. I have also tried to slide and remove the con rod from crankshaft. But unsuccessful ....how to dissemble the STS .28? Thanks you very much

Maybe because the clip is not on the exhaust side, its is on the boost port side as per manual ?
http://www.stsrc.com.tw/download/21%...ual%20v3.1.pdf

Yep, some engines don't have a clip on the exhaust side.
To prevent the piston pin to come out, the piston pin hole in the piston is a bit smaller there......
But for balans reasons, most engines do have clips on both sides.

Some years ago, I've had an OS engine with no circlips at all!
The liner was rotated about 45 degrees, so the piston clip moved just between the liner ports......

All sts engine only use one wrist pin clip facing to boost port. The exhaust port is very hot so we cancel the clip. Wanna remove the conrod you can use zip-tie to fix the rod and pull it out. But it is danger if the piston fall. I would like to suggest you to disassemble the engine after the break-in process. When you break-in engine the engine will clean itself. You can use some fuel to rinse the engine that is enough. Don't need to disassemble it fully. Just remember don't over-rev when break-in.