Topic: Seized Engine help

[kansassteve]

Hi, I recently bought a 1976 CB550 with a seized engine. The motorcycle has not been touched since around 1988. On getting the bike home I took off the points cover and put a 23mm wrench to the nut used to turn the engine in order to time the engine. I thought this may be able to tell me if she was completly seized or just a bit stiff. To my horror I broke two tiny tabs and the long bolt that screws inside the engine. I guess I can use an 'easy out' to get the rest of this bolt out, but where can I get replacement parts??. Have I done more damage than I think??  I hope someone can help me, thank you, Stephen

[bryanj]

You can get a nos advance unit from www.davidsilverspares.co.uk if you remove the lh cover (generator) there is a bolt there you can try but i would remove the spark plugs and fill the bores with diesel first to try and break any rust seal. Dave has most parts so it would be best to wait till you know everything you need before ordering

[SteveD CB500F]

Go with Bryan.
If it's sat that long, another couple of days won't matter.
Put diesel down the plug holes and let it soak for a while.  Then post back if it still won't move (there are other ways described elsewhere on this site for freeing up a siezed engine.)

[kansassteve]

I can't find the 'other ways to free up a seized engine on this site', can you tell me where to look? thank you, Stephen.

[paulscb750]

hey i just had a seized engine on a 73 cb750 that had been sitting for at least 10 years. i tryed diesel down the cylinder and let it sit for a week but it did not work so i got a DH40 (a electris cement breaker) and addapted a special bit and used that to drive the picton out. it was the only thing that worked. So use that as a last ditch effert. U will probely have to replace a picton and bore out the cylinder. so good luck

[n9viw]

One trick I learned from a Yammy site was to break the porcelain out of a spare spark plug and use that as a threadable form into which you can mount a quick-release air chuck or a Zerk grease fitting. Thread it into one cylinder hole and take all the other plugs out, and make sure the valves in the cylinder in which you're working are closed all the way. Hit it with air (or pump it full of grease), and it should move.
If this doesn't work for you, those sleeves may be toast. Strip the engine and send the cylinder (with pistons, obviously) to your local machine shop and ask them to get them out with the least amount of damage. You may need to get the cylinders rebored, but if it's seized, you'd need to do that anyway.
Something just occurred to me- have you tried to freewheel the bike? If the primary chain broke, that may seize it just as well as a frozen piston would. Also, check to make sure it's out of gear and the clutches are free. My wife's old CM400T had sat since 1996 with all the old fluids in it, and it took a good piece of work to get those clutches free.

[SteveD CB500F]

Search the Greenspun Archives (previous home for this site):

http://www.glennstauffer.com/smf/

[Bryan Boyle]

another thing I've gotten good results with in the past is something we use
at the hangar called "Mouse Milk".

We use it to free stuck AN bolts in bushings, stuck al/al fittings, etc.

Works a treat.  Helps if the metal is slightly warmed (squirt a couple ounces down the hole,
put the engine in the sun for the late morning/early afternoon).

Just another thought.