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The secret to a successful motor rebuild: Time

I wanted to make sure that the bikes would be fresh for 2016 and have a reduced chance of grenading under the stresses of racing.  Starting with Laura’s 250 I decided to do a tear down and re-bearing due to the unknown amount of street and track miles.  Also in the previous season I had over-revved it a few times on accident with a downshift while at redline.  I am happy to report that this process ended up being successful and the motor ran great for all three days at Buttonwillow.  Behind the scene however is the amount of time that it took to do what on paper was a simple bearing replacement.


Nothing is ever that simple.  The motor and bearing were in surprisingly good shape.  Only the rod bearings showed any significant wear and even those were nowhere near ready to let go.  Everything was cleaned and inspected.  The sizes of bearings were noted and ordered along with gaskets, rod bolts, head bolts and piston sets.  A few head bolts had been damaged in removal so new ones were in order.  The pistons showed some scuffing and lots of carbon.  The wrist pins were tight and not smooth in the pistons like they should have been.  So I ordered a set of Weisco piston kits that came with rings and were only slightly more than just OEM ring sets alone.  Rod bolts are a torque to yield kind of item so its always good to replace.  IMG_4088
The problem is in inventory and shipping.  I knew that it took about a week to get in OEM parts and from an online retailer that would usually mean 2 weeks to my door.  This is OK except that when I finally received my shipment the rod bolts had mysteriously become wing bolts for an ATV air filter.  Days after a stern email was penned I got a response and new ones began their journey to me.  All this while I had one piston in hand.  Stock on another web-store was wrong and I had to wait for back-orders to be filled.  THREE weeks later I was able to finally source another more expensive piston from a third store and cancel the first one.  At this point well over a month has elapsed since I first split the cases and I don’t even have all my parts yet.

After three late nights of assembly I stuff the poor ninja’s heart back in its chest and crank it up.  I am rewarded with an immediate heartbeat and a bonus of no leaks.  The amount of time and uncertainty that went into this build unfortunately postponed the rebuilding of the GSX-R motor.  I will leave that for another time and another caffeine induced heart murmur.

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