I’ve pulled down my trusty 82’ R100, it’s got about 160K k’s or 100K miles on it. I’m just looking for some advice/opinions on the condition of the bearings, crankshaft surfaces etc. I will be doing some measuring to make sure things are in spec. Obviously there’s some wear but I can’t see any major scoring or gouging. The engine was running OK before I pulled it down, I’m in the process of painting the frame etc. and wanted to freshen up the top end of the engine but given the age of the bottom end I thought it was time to check it out.The bottom end of this engine has never been touched(I’ve owned this bike since 1984). My son and I are doing it together as a bit of a project.
It was probably lucky that we did pull the bottom end apart because after we removed the front main bearing carrier I noticed a small piece of wire stuck in the oil hole at the bottom of the carrier turns out it was part of the dreaded non return valve hidden in the rear of the oil filter hole.If I’m reading the oil flow diagram for the engine correctly ? the oil flows up toward the front main bearing so it’s bearing destroying journey was halted.
My plan is to replace all the bearings etc. then maybe install a 320 cam etc.
Thanks
Mark
Canberra Australia
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Realize that engine building is an art and science unto itself. There is no way I can tell you everything you need to know. I highly suggest you seek professional help for reassembly of the "short block".
Most of "correct assembly" relies upon correct marking of the parts before disassembly. To which most people respond with "Oops !"
I also suggest your short block be assembled with 'engine build lube'. If your mechanic doesn't use it, go buy it for him to use on your machine, or.... go find a better mechanic !!
• There is no wear to the crank in the center where the oil groove is. If you can measure a difference between the middle and either side then the crank needs help. Measure at several locations around each journal, both radially and axially, checking for "ovality".
• I wouldn't expect to see much, if any, journal wear, the inserts are not down to the copper. You've got a good cover of gray babbit showing that indicates good oil pressure.
Hope this helps.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
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