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Saturday, May 1, 2010

Pistons, Rings, Cylinders

Let's get this motor back together.

We have to replace the pistons with the oversized pistons.

Take out both wristpin snap rings and throw then away.





Gently tap out the wristpins. The screwdriver's handle made a nice soft drift.



Out it comes.



Old piston is gone.



Repeat the steps for the other piston.




Remember I said throw away the snap rings? I forgot to order those with the rest of parts and I had to scramble to find some locally or wait another week to build. I had to drive 60 miles one way to these. I needed 4, they had 6. I bought them all just in case.




The pistons have a directional arrow so you want to the first one snap ring into the groove the will be on the camchain side of the cylinder. This will make second snap ring easier to install without working around the extra studs in the case.



Slide the ring so that the gap in the ring is opposite the gap in the piston.



Oil the piston where the wristpin rides.



Oil the wristpin and the connecting rod hole.



Line everything up and put the wristpin through the piston and connecting rod.



Install the other snap ring.



Again move the gap of the ring opposite the gap in the piston.



Yea! Piston is on.



Get ready to do the piston rings. READ THE BOOK! It is easy to put the piston rings in upside down, backwards, gaps misaligned or otherwise wrong.



Work the rings into the grooves.



Ringed and ready.



Oil the rings and the pistons.



Old Easyrider trick, use a hose clamp as ring compressor. This is $2.95 dryer vent clamp with quick disconnect from ACE Hardware.




Oil the cylinder wall.



Slide it on.




Take the hose clamp off, when the rings are inside the cylinder.



Looking good.




I looked up the torque value on these two nuts. 18 ft*lb. I then realised I could fit a torque wrench on it. I used my calibrated elbow instead. (Add torque adaptors to my Christmas list.)




The next picture should both cylinders on with pistons in them, but we fought the rear oil rings for 2 hours maybe. The wavy oil ring would not go in. It acted like it was too big or something. Here it is laughing at us.




Plan B. Put the piston into the cylinder on the bench then attach the piston to the connecting rod. Take out one snap ring and the wristpen. We used a 14mm socket and extension as drift this time to clear the installed snap ring.



Work the piston and rings into the cylinder on the bench with the wristpin hanging out.



Now put the cylinder, piston, rings, and wristpen onto connecting rod.


Tap the wristpen through and put the other snapring in.


Now we're done for the night.

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