Yamaha RZ350 YPVS

Engine Rebuild

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The bike sat for several years while I was in the military.  My plan was to break the bike down and clean it up, but I figured I should take the head off and check the pistons and cylinder walls.  The right side had some piston damage to it and slight scoring of the cylinders--time for a rebuild--1st time the engine has ever been apart.

 
 
 
The right cylinder had light scoring, could barely feel it with a finger nail.  I probably could have gotten away with honing the cylinders and replacing the pistons but wanted to do it right and without any worries.  Piston damage was to the top of the piston and any metal that broke off likely exited via the exhaust port.  The left side showed no evidence of damage to either the piston or cylinder.

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Right Cylinder

Had a real difficult time with the power-valve coupler--both screws ended up stripped due to rust--got the engine out of the frame and used a dremel to cut new grooves in the screws and they finally came out.  While I was at it, I wanted to figure out why I blew a piston too.   While cleaning the carbs and putting a dyno-jet kit in, found that the balance tube between the carbs was missing--making the right side run lean!! 

 

Check out the before and after of the power-valves--I had no idea that they were supposed to be silver.  This was a long and meticulous process!!  Baked.

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Power-valves: One clean, one obviously not!

While it was apart I painted the case, side covers, and cylinders.  I also had to replace some wiring since a mouse crawled up into my primary cover and chewed into the neutral switch and other wires!!  Bike is now standard with a mouse trap built in.  This is a bit of the process.

TAKING IT APART
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I did not intend to take the engine out of the frame, nor to rebuild the entire bike.  It was one of those spur of the moment things. 

TEAR DOWN
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My girlfriend is watching me clean the bike, she goes down to the apartment to get us drinks and when she comes back this is what she sees!

ALL APART NO TURNING BACK
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I had just purchased the yellow tank to replace mine that had several hundred pin holes in it!!  That was my second tank already too--happens to most at one time or another.

ENGINES OUT--CYLINDERS OFF
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She needs a top end rebuild, a serious paint-job, and before any of that, it is dirty as hell!! 

CYLINDERS NEED SOME ATTENTION
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Cylinders before they went out to get bored--have pics of them after bore that I will eventually find and put on here--before paint too obviously.

FRESH PAINT AND NEW PISTONS
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All cleaned up and painted.  Pistons are on and ready for cylinders.  Actually found some rubber grommets buried in dirt when I cleaned the case up--it was a mess.  Pulled the original clutch out of it too and replaced with a new one--GET NAME LATER!!
SIDE VIEW OF PAINT AND PISTON INSTALL
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I did not get any pics of the clutch replacement--still had complete original assembly in there to include the rubber o-rings.  It still worked fine, but it was another part I figured I would replace while I had it all out.

CYLINDERS PAINTED AND BACK ON
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Heads slid on no problems and power-valves went in without any issues either.  Used SS screws on the power-valve coupler so that maybe it wouldnt give me such a hard time on the next rebuild. 

DIFFERENT ANGLE OF CYLINDERS ON--READY FOR HEAD
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Ready for the heads.  I hated that I had to do this because when I took the head bolts off initially I had to pry the head off, and it let out a noise like I was opening a soda bottle--I would have liked to leave it alone with that kind of seal after 20 years!!

HEADS ON--CARBS ON FOR PICS SAKE
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Got it pretty much all together.  Carbs are in place just to get some pics... still not ready with the rest of the bike to put it all back together. 

LOOKING GOOD
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Stripped the paint off the thermostat housing and the kickstarter--I like the contrast of the black and silver.  I also installed a SS bolt set on all the covers.  Nice allen head stuff I got off of ebay--let someone else do the work and find the proper sizes!

FINAL ASSEMBLY COMPLETE--NOW THE REST OF THE BIKE
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I have since purchased a boost bottle to throw on there.  I dont plan on doing it for the initial startup though--dont want to change too much before it runs again.  I'll get it running again then start to make changes gradually so I dont completely loose the tune that I had before the rebuild.

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