Engine Rebuild on Enticer Question

[800tundra]

Trying to fix up old Enticer 300 for kids.Cylinders were bored to first over size. New .10 oversize SPI pistons (Size Stamped on top),Ring end gap was checked when bored at machine shop. Assembled it, checked compression on both cylinders 80psi each. Verified with another tester. Ran it a while ,no change.Pulled cylinder off. Checked height with old piston, it is same, rings installed correcty and piston proper way. WTF!! Any suggestions??

 

[yammi4ever]

If everything specs out I would say the rings haven't seated yet. Did you hone it any after the boring? I would say run it some more and see if it gets better.

 

[800tundra]

Yes Honed after. Starts runs fine also. Will keep runnin it as Not going to spend more money on this thing

 

[apex jeff]

Trying to fix up old Enticer 300 for kids.Cylinders were bored to first over size. New .10 oversize SPI pistons (Size Stamped on top),Ring end gap was checked when bored at machine shop. Assembled it, checked compression on both cylinders 80psi each. Verified with another tester. Ran it a while ,no change.Pulled cylinder off. Checked height with old piston, it is same, rings installed correcty and piston proper way. WTF!! Any suggestions??

Most of the time piston to cylinder wall clearance is far more important than ring gap. Call SPI and get specs. If I remember,yamaha first over and second over sizing is metric with oem pistons. Hopefully cylinders were not bored without pistons on hand. Yamaha oem pistons run a tighter tolerance than aftermarket pistons because they tend to grow less when hot. Sounds like you may have an overbore issue. Good luck.

 

[800tundra]

Anybody have a contact number or website I can go to for SPI

 

[SylvanLaker]

I you want a hand, call me at the shop and I can help you.. your cylinders could be out of round, Cyl to piston clearance could be wrong. could have leaks through o-rings..