Kahoy
CB750 Member
Hello everyone! I'm a new member on this site and this is my first post and plead for help.
My project is a Honda 79CB750K that was in storage since mid-80's. Very low mileage bike and I'm also the original owner. Due to improper storage and harsh storage condition the engine on the bike seized. To free the seized engine, I took all plugs out and pour penetrating oil in the cylinders and let it do its job for a couple of days. I also stored it in a heated garage. Then I put the bike on 5th gear and start rocking the bike back and forth until I can see all the pistons move up and down. That took couple of hours. Almost time for celebration, but noticed a problem I could not figure out. When the piston start moving easy, I took out cover for the generator to access the crankshaft. So with a 17mm box wrench I continue to turn the engine. To my surprise, I could only turn the crankshaft approximately 1-1/2 revolution and it would stop. I could turn it the other direction with the same outcome. I'm don't want to apply too much pressure since I'm not sure what causing the problem. When this bike was put on storage it was running and nobody touched the bike since then.
From what I saw it appears that pistons for cylinder 2 and 3 may not be reaching the TDC. I need to measure and perform accurate measurement. My statement was based on using a screw driver sitting on top of the piston. i just though I share that clue.
I'm looking to see if anybody had similar experience and perhaps could point or suggest to me the things to look for to further investigate the cause for the blockage (for the lack of better word) and solve my problem. I'm tempted to open the valve cover and cylinder head but not sure what to look for. This is my first venture with this engine. I currently ride a bike with a boxer engine.
I would appreciate any thoughts you guys/gals may have. Thank you in advance - Nino
My project is a Honda 79CB750K that was in storage since mid-80's. Very low mileage bike and I'm also the original owner. Due to improper storage and harsh storage condition the engine on the bike seized. To free the seized engine, I took all plugs out and pour penetrating oil in the cylinders and let it do its job for a couple of days. I also stored it in a heated garage. Then I put the bike on 5th gear and start rocking the bike back and forth until I can see all the pistons move up and down. That took couple of hours. Almost time for celebration, but noticed a problem I could not figure out. When the piston start moving easy, I took out cover for the generator to access the crankshaft. So with a 17mm box wrench I continue to turn the engine. To my surprise, I could only turn the crankshaft approximately 1-1/2 revolution and it would stop. I could turn it the other direction with the same outcome. I'm don't want to apply too much pressure since I'm not sure what causing the problem. When this bike was put on storage it was running and nobody touched the bike since then.
From what I saw it appears that pistons for cylinder 2 and 3 may not be reaching the TDC. I need to measure and perform accurate measurement. My statement was based on using a screw driver sitting on top of the piston. i just though I share that clue.
I'm looking to see if anybody had similar experience and perhaps could point or suggest to me the things to look for to further investigate the cause for the blockage (for the lack of better word) and solve my problem. I'm tempted to open the valve cover and cylinder head but not sure what to look for. This is my first venture with this engine. I currently ride a bike with a boxer engine.
I would appreciate any thoughts you guys/gals may have. Thank you in advance - Nino