Author Topic: 1981 CM400C Help Needed  (Read 900 times)

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inkundone

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1981 CM400C Help Needed
« on: July 31, 2008, 05:20:13 PM »
I've got a 1981 Honda CM400C that the cam/timing chain just broke on. I was pulling into my driveway and it blew.

Should i even bother trying to fix this or should i just toss in the towel? I know nothing about hondas and i really dont wanna spend 600 bucks on a bike that is really only worth like 500.

what should i be looking for when i tear this apart?  I took off the valve cover and i can almost pull the chain out in one piece, except its snapped in half.


any insight would be helpful.

Offline bryanj

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Re: 1981 CM400C Help Needed
« Reply #1 on: July 31, 2008, 08:24:22 PM »
Its an expensive rebuild:-

Cam chain
tensioner
full gasket kit
balance chain
time
patience
tools
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

inkundone

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Re: 1981 CM400C Help Needed
« Reply #2 on: August 01, 2008, 12:23:19 AM »
i have the whole top end of the motor torn apart right now. the pistons look fine, the valves dont look bent from the tests that ive done, and the whole chain came out fairly easy as I cranked the motor over, however i'm used to harley motors and not hondas so this whole cam chain versus push rods is different to me.  i have no manual on the specs or how to tear this thing down so im basically flying by the seat of my pants right now.  anyone know where i can find a good complete engine spec and tear down book? i have the clymers book and it doesnt really help a whole lot.



Offline Uncle Ernie

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Re: 1981 CM400C Help Needed
« Reply #3 on: August 01, 2008, 04:44:23 AM »
www.repairmanual.com  is the first place I look for manuals. 
Good luck ~
Dude- your 8 layers are showing!

Offline Johnie

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Re: 1981 CM400C Help Needed
« Reply #4 on: August 01, 2008, 05:55:44 AM »
I have the '81 CM400C and also a CM400E both restored, but have been lucky enough to not have a cam chain problem.  Actually, have not ever heard of the 400 having this happen.  I got my Honda service manual from Helms.com  You will find it pretty complete and it covers all the 400's.  Wish you the best in your rebuild.  They are fun bikes to ride.
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