I noticed a slight bit of oil vapor on the Left side by the cylinder / head joint. When I re torqued the head I found that the bolt facing upward (#9 in the tightening sequence) was loose. I tightened them all & re adjusted the valves etc.. Bike ran great & a slight miss on that side was gone at first. Then after a good run of 100 miles or so the miss came back, the oil leak worsened & I found the bolt was loose again. Now going to pull the head & just wondering what the most common reason & what I will likely find?? We're all 1973 850's heads Heliocoiled? Will it likely need to be shaved flat??? Or is it possible just the bolt failed. Thanks,, GLENN T.S.
850 head bolt loosening..
- Thread starter gtsun
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- Dec 10, 2008
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gtsun said:
That is a very common problem. The fine threads in the aluminum head fail. Installing a fine thread BS helicoil will fix it for a while.
Better is an American course thread helicoil. Different studs will be needed.
Best is the aluminum bronze inserts I do. Jim
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