Honda CB750 Sandcast
The Restoration Shop => Engine Mechanical => Topic started by: Wayne on December 14, 2010, 12:24:22 pm
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When overhauling a SOHC 750, besides the obvious what parts should be looked at as far as a "must" to replace. Are the cam and primary chains on the list of "put them in regardless"?. Kickstart return spring to be on the safe side? Things like that. Just looking for some input so I have a sound/reliable engine but also not throwing money away where I don't need to.
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Wayne this is a great question and i will be interested to see what others say. I have my own thoughts, but will reserve them because i am sure others will say much of the same.
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I never want to go back in the engine, I always replace the ball bearings. valve guides, valves, chains and chain guides, pistons, rings, rist pins, pin clips, seals and gaskets for piece of mind. Do not buy NOS seals, buy new oem rubber seals from honda. I mic/inspect all the valve springs. shafts, bushings in the gears, thrust washers (check the dogs and drives for ware), shifting forks and replace any parts that don't meet spec. Grind a 3 angle seat in the heads, hand lap the valves, bore job. If the crank journals look fine and mic out ok I reuse the bearings, if not grind the crank and replace the bearings.
How are you going to prep the aluminum prior to painting. PPG make an etching solution and a sealer I use prior to painting or clear coating.
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I agree, great question and timely for me as well. I don't normally replace bearings, pistons and pins, valves and guides, if they look good and are to spec. I will be replacing every bearing on #97 however. I do replace all gaskets and everything rubber although I've used cam chain guides if they look OK. I agree with inspecting everything else.
Mark
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Thanks so far guys. I will be going through the reciprocating mass to ensure everything is 100% and to spec. That includes brgs, crank, rods, pistons, measuring cylinder wear/taper etc. The head will be completely rebuilt with new valves, springs and whetever else it needs. I'm real believer that a good head rebuild can make or break a motor job. Multi angle valve job, proper seat widths, checking spring pressures at installed height and installed spring height are critical in my mind. The head will be done by a professional service.
1941wld says cam and primary chains should be on my list. Certainly gaskets, seals O rings etc. Anything else inthere that might let me down?
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Replace valve guide seals with viton type.