Author Topic: checking bottom end when doing top end rebuild????  (Read 661 times)

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Offline andyxlh

  • Full Member
  • Posts: 586
  • Country: au
  • '89 XLH '96 FLHR '73 125RC, Sydney Australia
checking bottom end when doing top end rebuild????
« on: August 03, 2009, 10:12:27 PM »
Hello folks
I've also posted this in general topics...
I'm into the top end on my '89 sportster, and have stripped it to the rods. The bottom and has done about 50,000 miles since its last rebuild, so should be OK and wasn't making any horrible noises before stripdown (but was using a lot of oil). The top end was not replaced whne the bottom end let go, (I was on the road trip of a lifetime in 03 and did the strip down in the Santa Fe dealer car park) just a new set of rings, and has done about 70,000+ miles since its last set of pistons. The bores were a little scored buy the bottom end letting go. Whole engine 100,000mi.
Anyway, having removed the pistons I was having a bit of a look and noticed that there is a VERY slight side to side movement of the rods - the front much more than the rear which has almost no movement at all. I guess that is due to the 'knife and fork' arrangement of the rods on the crank pin. There is no 'up and down' play at all - I know that is a sign of rebuild needed, but how much side to side movement should there be? I remember a mechanic telling me that a little rod mvement to the side is OK but I guess I'm just being paranoid too...
The reason I'm a bit worried is a lifter let go about 85000mi and ruined a cam, I think I got all the pins that fell out but...
If you can't fix it with a hammer and a roll of Duck tape then you're in trouble