Rusted stuck pistons

M

msch345

New Member
Does anyone have any suggestions for me to try before I crack open the motor? I acquired a 68' CB160 a couple of weeks ago that sat in a Wisconsin garage for about 25 years. Needless to say, the pistons are rusted stuck... I've sprayed a bunch of PB Blaster in the spark plug holes and in the caps over the rocker arms. I still can't get them to pop... Any ideas would be greatly appreciated.

Thanks in advance!!!
 
+1. Even if you got them unstuck with the motor together, you'll just end up doing more damage to the motor if you try and fire it up.
 
Seems like if the pistons are rusted in place then there's probably more rust to be found.
 
Thanks for the suggestions to just pull the motor and go from there. I realise that I will have to do that anyway, but it looked to me from everything I've read on this site, that it is best to try and free up the pistons while the motor is on the bike by rolling it back and forth after putting some sort of lubricant in the motor. I guess I was hoping for some magical advice from you guys on what else I can do while I have the motor on. Thanks again guys, I am fairly new to the whole getting a non-running bike and trying to make it run thing... My experience has been limited to trying to get my bikes in running condition, then trying to work through kinks from there... I just couldnt pass this one up, I have LOVED these bikes for a long time!!!
 
Leave the motor in the chassis,,find the crankcase vent and attach a funnel,,,fill with diesel fuel(CHEAP),,,,,let it soak!!!!!!!!!! pull a engine side cover and torque the crank shaft,,if it breaks free,,great ! now tear down the motor,,if it doesn't :'( pull the motor and salvage whats left of it.......
 
Thanks again for the suggestions, I think I'll try the deisel fuel idea next! So once I get the pistons free (hopefully) what are the standard things I will need to replace? Just gaskets? Or is there something else that I should do besides making sure all moving parts are clean and moving...
 
You need to just check everything.
check rocker arm pads and cam shaft for pitting, check beaings turn smooth, check gear teeth for rust.
Check valve faces and seats for rust/pitting.
Usually, its Ok if bike was stored somewhere dry, just cyclinders will need clean up.
Usually only one piston is stuck because valves on one cylinder are open while other is closed (unless you got real unlucky and one intake, one exhuast were open)
You will probably have to bore first oversize, I've never seen stuck bike that didnt have at least 0.005"~0.010" depression from rusted rings.

PJ
 
Diesel is the route to go. Hope you have good luck with it, those bikes are sweet! Sound like Triumphs, and look awesome! Check the cam lobes, and the head, as the cam turns in the alloy and if the oil way was blocked to the cams, big trouble.
 
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