Since I can't seem to find how to post a new topic on this forum, I guess I'll just reply to this one!
I just rebuilt my Polaris 700 engine due to a failed end bearing - new SPI pistons, new rods with upper and lower bearings, all new main bearings, and cylinders honed. Basically everything but the crankcase and jugs are new. The crank was rebuilt by a mechanic but I did everything else. I followed the procedures in the manual very carefully and made sure that the ring gaps were within spec (just over minimum). After reassembling everything I went to test start the engine. I was extremely surprised to see how hard it turned over (manual pull, not electric). The engine had 9000 miles on it so it was pretty loose prior to the rebuild but I can't believe how hard it pulls now. It runs well so far and started after the second pull. I really need to hang on to the handle when pulling or it will get ripped out of my hand. I'm wondering if this tightness is normal for a new engine. I did a compression test and it read 110-115 psi, which seems low/normal. I was expecting a much higher reading based on how hard it pulled. Is it normal for a new engine to be that tight? What could be causing this if it isn't normal? Thanks!
I just rebuilt my Polaris 700 engine due to a failed end bearing - new SPI pistons, new rods with upper and lower bearings, all new main bearings, and cylinders honed. Basically everything but the crankcase and jugs are new. The crank was rebuilt by a mechanic but I did everything else. I followed the procedures in the manual very carefully and made sure that the ring gaps were within spec (just over minimum). After reassembling everything I went to test start the engine. I was extremely surprised to see how hard it turned over (manual pull, not electric). The engine had 9000 miles on it so it was pretty loose prior to the rebuild but I can't believe how hard it pulls now. It runs well so far and started after the second pull. I really need to hang on to the handle when pulling or it will get ripped out of my hand. I'm wondering if this tightness is normal for a new engine. I did a compression test and it read 110-115 psi, which seems low/normal. I was expecting a much higher reading based on how hard it pulled. Is it normal for a new engine to be that tight? What could be causing this if it isn't normal? Thanks!