Topic: Crank Case Top

[camshaft1991]

So I am really up a #$%* creek.. I broke my cam chain tensioner bolt last October on my 72 Honda CB350F. I disassembled the entire engine to get to it and inserted an easy-out and it broke flush inside like the broken bolt. On top of all that a friend of mine said he would machine it for free. The threads are gone, the hole looks like a funnel, and both the bolt and easy-out are still lodge inside.. My question is should i pay to have it machined out (by a machine shop) and threaded for a new bolt or buy a new top to my crank case? I found a top case for $50. Would it be able to fit with my current bottom case or should i just buy an entire case? 

[mystic_1]

I'm not certain about the 350F but on 750's you CANNOT mix-and-match case halves because the crankshaft journals are line-bored with the cases mated.  In other words if you mix-and-match you destroy the alignment of the crank bearings.

From the sounds of things a decent machine shop should be able to get you sorted out.

mystic_1

[camshaft1991]

I'll try to get some quotes today and figure out what to do. I heard boring it out to one size can cause a slight oil  leak from a post I read. I'll have to get a machinist's opinion


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[camshaft1991]

Found out it would cost a minimal of $175 to drill out broken bolt, broken easy out, and the damage my friend did by causing everything to fuse. Would of cost me $35 if I brought it to them with the broken bolt. Word of advice don't use easy outs and don't let your "friends" do it for free. Now I'm going to have to buy a new case


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[camshaft1991]

And the can chain tensioner rod could be destroyed in the process


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