engine mount alignment

[jBernard]

FINALLY have my cnc'd engine mounts coming that i drew up a while back. one thing i wanted to ask (guess its a bit late now, ha!) is about the alignment from side to side.
I mic'd the ID of the engine bolt holes (crankcase/lower rails join holes) and of course since the engine cases are cast then either left raw or quickly bored thru, it still leaves each thru hole +-.015 on my 99' engine.
Being paranoid, obviously in a dream scenario you'd want perfect thru hole alignment from one side to the other, with only +.005" or so for bolt play. This obviously isnt going to happen unless you could ream the engine cases to a perfect number then get some custom OD shank bolts to use.
Whats everyone else doing? Bending/tweaking to get alignment when you put your engine bolts in? Think there is concern there that it might be nice and tight on one side fitment then opposite side has some 'slack'. Obviously this is the heaviest part of the bike and its trying to go the opposite direction most of the time and having the most rigid setup possible is best.

Let me know what you think.

will post pics soon, hopefully final frame welding done within a week. also have some cool headstay brackets i designed, will see how they work!

Taylor

[don46]

True enough that the motor could have some movement while loose in the cradle with the swingarm bolt through but not tight. Consider that the motor cases are true on the sides and the swingarm bushings are true, so once you tighten the swingarm pivot bolt you should be square, if your concerned you may have to move the motor while tightening the bolt to maintain square and then build your motor mount brackets. I wouldm't worry to much, all of the flat surfaces are true, I've built 7 hybrids and have never had an issue with alignment, in fact till you mentioned it I never gave it any thought, other than the countershaft to swingarm pivot alignment

[ssimonson764]

What I did on my build is worked my way from the swing arm pivot to the front. I put the motor in the frame with the swing arm bolt, put the bottom mount bolt through the loose brackets and the motor then positioned the motor to where I had the best counter shaft to swing arm angle, keeping in mind pipe clearance, then put a small weld on the brackets to the frame. I then removed the motor and completely welded the bottom brackets to the frame. Put the motor back in to measure for spacers between the cases and the brackets. The motor pretty much lines itself in the right place when the swing arm bolt is in. Doing this method mount by mount works well to assure perfect alignment. I hope this helps.