Rear head to seat post clearance?
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Hog54
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Rear head to seat post clearance?
I took my heads off my bike last night and I noticed that the rear head has been hitting up against the seat post.And I know it wasnt when I put the bike together a few years ago because I can remember checking it.Is this common on pans for the most part and is there anything I can do to stop it?Or should I just leave it?
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rrhawg
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Re: Rear head to seat post clearance?
The first thing I would be looking at is the frame to make sure it's not broken, they often crack just above the rear motor mount. The next thing is the motormount bolts if they come loose the case can move and wear the mounting holes and decks. The motor will grow when it's up to temperature which I suppose could also cause this.
Rich
Rich
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Hog54
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Re: Rear head to seat post clearance?
Well the motor mount bolts were never loose and the frame isnt broken.I just know that I have seen alot of bikes do this and I have read about it.I just want to know what to do about it.The first thing comes to mind is shim the rear mount.
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fourthgear
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Re: Rear head to seat post clearance?
Your mtr could of still walked back with time & vibration , even though the bolts were felt to be tight .
If frame / case bolt holes have been opened up from age or torque from operation , they can be shimed by an insert to make the fitment of the mtr mount bolts more percise. A custom shanked or shimed bolt may be the least expensive route , if this is the case.
My 65 upper mtr mount had a bunch of small cracks in it ( probably because of the none stock, two piece upper mtr mount that was on it when I bought it ) nothing to hold back the expansion or should I say contain it .
I had to remove all the paint from the upper mtr mount ,to find the cracks & have them repaired .
I also use a tapered punch to alien the mount holes in front & tighten the back ones ,than I check for any shimming in the front.
I have also found ,any paint on these surfaces will let them move in time ,but of course you know most of this , I had to say it any way.
If frame / case bolt holes have been opened up from age or torque from operation , they can be shimed by an insert to make the fitment of the mtr mount bolts more percise. A custom shanked or shimed bolt may be the least expensive route , if this is the case.
My 65 upper mtr mount had a bunch of small cracks in it ( probably because of the none stock, two piece upper mtr mount that was on it when I bought it ) nothing to hold back the expansion or should I say contain it .
I had to remove all the paint from the upper mtr mount ,to find the cracks & have them repaired .
I also use a tapered punch to alien the mount holes in front & tighten the back ones ,than I check for any shimming in the front.
I have also found ,any paint on these surfaces will let them move in time ,but of course you know most of this , I had to say it any way.
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Bosheff
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Re: Rear head to seat post clearance?
Front and rear motor mounting areas areas on the frame are best left unpainted so that the engine will be grounded to the frame....bosheff