Stevepasc
New Member
Was gifted a 1980 CM400T a couple months ago by a friend of a friend who just wanted it gone. When I picked it up it didn’t have keys, and had sat outside (under a bush or a tree) for over a decade. It was last registered in 2014, and probably hasn’t run since then. A few things I noticed that needed replacing right off the bat:
-no keys: needed a new ignition switch and gas tank lock, switch replaced, gas tank still inaccessible, probably rusted inside
-carbs all gummed up and varnished : cleaned carbs with ultrasonic cleaner and used 4into1 rebuild kits, cut off valves and accelerator pump diaphragms were brittle and were replaced with 4into1 rebuild kits as well
-no spark at spark plugs: tested ignition coil and out of spec for resistance, replaced with AC Delco ignition coil mod
-front master cylinder damaged: needs replacing
-brake caliper: seized open: needs caliper rebuilt
-front tire flat, back tire old and needs replacing, plan to replace both when more ride ready
Additional work already done:
-old oil drained out and oil filter replaced with new filter and 15w-40 Rotella T4 motor oil
-old glass style fuse box replaced with new modern blade style fuse box
-Replaced both throttle cables and clutch cable
After cleaning and rebuilding the carbs, changing the fuse box and ignition switch, replacing the ignition coil,replacing cables and changing the oil I put a battery into it and was able to get the engine to start and idle. It ran alright but was blowing a lot of smoke. After running for ~10 mins amount of smoke reduced but was still a little smoky. I compression checked the engine and the left cylinder was at ~150 psi, right was around ~80 psi.
Next: sync and tune carburetor. Adjust valves. Pour small amount of oil into right cylinder and determine if compression loss is from piston rings or valves. Valve cover gasket is cracked, I purchased a gasket kit for the entire engine, so I have them to replace that cracked gasket as well as the ones for the head gasket in case I do need to replace piston rings. Get key made for gas tank cap lock and check condition of inside of gas tank (probably rusty, gonna de-rust with vinegar). After determining compression loss issue will replace master cylinder and rebuild caliper. Previous owner also put a set of short straight bars on it, (and removed the front fender) so brake line, and other cables run really close to front tire… will probably go with some taller bars to fix that issue. After brakes then will replace tires.
Don’t have a title for it, or even a bill of sale, so trying not to dump a lot of money into a bike I can’t really sell, more just a fun project to see if I could get it running after sitting for over a decade. Will probably end up selling it to a friend for enough to cover the parts and a couple cases of beer
-no keys: needed a new ignition switch and gas tank lock, switch replaced, gas tank still inaccessible, probably rusted inside
-carbs all gummed up and varnished : cleaned carbs with ultrasonic cleaner and used 4into1 rebuild kits, cut off valves and accelerator pump diaphragms were brittle and were replaced with 4into1 rebuild kits as well
-no spark at spark plugs: tested ignition coil and out of spec for resistance, replaced with AC Delco ignition coil mod
-front master cylinder damaged: needs replacing
-brake caliper: seized open: needs caliper rebuilt
-front tire flat, back tire old and needs replacing, plan to replace both when more ride ready
Additional work already done:
-old oil drained out and oil filter replaced with new filter and 15w-40 Rotella T4 motor oil
-old glass style fuse box replaced with new modern blade style fuse box
-Replaced both throttle cables and clutch cable
After cleaning and rebuilding the carbs, changing the fuse box and ignition switch, replacing the ignition coil,replacing cables and changing the oil I put a battery into it and was able to get the engine to start and idle. It ran alright but was blowing a lot of smoke. After running for ~10 mins amount of smoke reduced but was still a little smoky. I compression checked the engine and the left cylinder was at ~150 psi, right was around ~80 psi.
Next: sync and tune carburetor. Adjust valves. Pour small amount of oil into right cylinder and determine if compression loss is from piston rings or valves. Valve cover gasket is cracked, I purchased a gasket kit for the entire engine, so I have them to replace that cracked gasket as well as the ones for the head gasket in case I do need to replace piston rings. Get key made for gas tank cap lock and check condition of inside of gas tank (probably rusty, gonna de-rust with vinegar). After determining compression loss issue will replace master cylinder and rebuild caliper. Previous owner also put a set of short straight bars on it, (and removed the front fender) so brake line, and other cables run really close to front tire… will probably go with some taller bars to fix that issue. After brakes then will replace tires.
Don’t have a title for it, or even a bill of sale, so trying not to dump a lot of money into a bike I can’t really sell, more just a fun project to see if I could get it running after sitting for over a decade. Will probably end up selling it to a friend for enough to cover the parts and a couple cases of beer
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