replacement crank and rod bearings

Joined
Jun 23, 2007
Messages
2
I have a 1972 Combat that has 9000 miles and the original crank and bearings. Is it a large expense to do the replacement if I do the work myself? I would appreciate any info. Still runs strong but I have heard it could go any time. Thanks
 
Joined
Apr 7, 2004
Messages
1,691
There are at least two good shops in the Atlanta area that could go through the bottom end for you fast and reasonable . Your time could be spent pulling and re-installing the mill and fixing up the harness that all the 72's need. For a bit of extra cash they might let you watch while asking silly questions once in a while. This would alleviate your fears and save you money still leaving lots to learn. Some times the question How much extra if I get to watch? Can led to the kind of leaning that could make you a better motorcycle mechanic. Just my opinion though.
 
Joined
May 19, 2006
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Simply stripping the motor to replace the mains (and big-end shells while you're at it) won't cost too much. Gaskets and seals are easy to price up plus a crank fittings set because it would be sensible to clean the sludge trap as well.

It starts getting pricey if you find any damage to the cam hardening and / or followers and if you find yourself replacing valves and guides, it will all start to add up.

Most of the time involved is in cleaning up components, gasket faces etc. before reassembly. It's quite feasible to have cranks out and on the bench while they're still hot to the touch :)
 
Joined
Jun 23, 2007
Messages
2
Bottom end bearings

Thank you both for your advise. I am actually an old wrench myself.
Used to work at Harley Northeast in Tucker before they went out in the late 70's. I've worked on a lot of bikes (Brit too) and have owned and maintained around 65 or so since the sixties, but my main concern was having the proper tools, and I didn't know the cost of mains. I do now.
But I also hear that if I drive sanely (under 120) and don't overrev I
might get considerable milage out of her. She only has 9500 miles and I was wanting to start riding her again. Do I even need to do the main
bearing fix right now? She still sounds good. All advice is welcome. :roll:
 
Joined
Apr 7, 2004
Messages
1,691
Well as you Know than, if every needed part and tool was on hand you would only need a day to pull it down and put it back barring a crank grind. Add a light hone, fresh rings,a bit of valve paste, The cleaning is the big time sucker. With your background I guy like RF Watley at Beno's in Winter GA, you clean, he uses all the service tools you guys could bang it out in a day. Money and time well spent because when you get on the seat of a 72 Combat your going to find yourself hitting the 7000 mark all the time. Trust me if you like old iron running down the road as much as I this isn't even a question. Without the sludge trap clean and a good oil filter fitted up you are at risk. Bearings be dammed. JMO you will really enjoy that day, and with your background and learn the whole deal in one day. If Richard can't help, we will make you an appointment up here in Michigan.
 
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