Author Topic: head bolt 79 650  (Read 1989 times)

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Offline crusierlover

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head bolt 79 650
« on: July 21, 2016, 09:35:14 AM »
I am trying to remove the head from my seized up 79 motor.I want to see what is binding it up.However the motor wont rotate-the basic problem-so I cant rotate the engine to loosen the little bolts holding the cam sprocket on.Plus with the tensioner bolt out,11 of the head bolts out,one head bolt is completely loose but wont lift out with a magnetic pickup tool wand type or a basket extractor wand type.It is the head bolt immediately to the left of the cam sprocket,header side.In clymers page 99 it is listed as the 4th bolt to loosen.If the head has snapped off seems like the magnet would lift it out of the hole.Or if the threads stripped seems like it would lift out.I can put the magnet on it and the head turns easily.Other than turning the motor upside down and shaking it to see if the bolt drops out which most likely wont work,I dont know what to try next.If I could get the cam chain to slacken,lift it off the cam,lift the cam out,perhaps that would take some pressure off.I have hit all around the head with a rubber mallet.Nothing breaks loose.I can go no further till this bolt comes out.All input appreciated.
Owner of 79 cb650.Non running.Current bike 2004 heritage softail. Denton Texas

Offline rb550four

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Re: head bolt 79 650
« Reply #1 on: July 24, 2016, 01:13:05 PM »
Have to soaked the rings with ATF and /or other things?
You will never get the head off with the timing chain and cam still bolted in it. Has to be removed.
   You can: #1. cut the chain and remove the cam , and get a new chain  when you rebuild it.   or
                  #2. put the headbolts back on, turn the tappets loose to be sure the valves are in closed position then hollow out a spark plug, screw in a grease zerkin the hollowed sparkplug, insert in plug hole and fill a cylinder with a high piston with grease until the pressure rotates the crankshaft. which will turn the cam.Then remove the cam bolt.
                   In either case at this point you should be able to remove the head/ turn the crank by wrench / break it all down.
                                              Sounds like fun right? It's all fun and games ya know.
                                                                    RB
A few Honda 500's, a few Honda 550's, a few Honda 650's, '72 cb 450, a couple 500/550/650 hybrids, and 2001 750. 
  550 Snowbike -Somebody had to do it.
  http://forums.sohc4.net/index.php/topic,101678.0.html             
http://forums.sohc4.net/index.php/topic,137317.msg1550907.html#msg1550907

Offline crusierlover

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Re: head bolt 79 650
« Reply #2 on: July 25, 2016, 12:14:35 AM »
Have to soaked the rings with ATF and /or other things?
You will never get the head off with the timing chain and cam still bolted in it. Has to be removed.
   You can: #1. cut the chain and remove the cam , and get a new chain  when you rebuild it.   or
                  #2. put the headbolts back on, turn the tappets loose to be sure the valves are in closed position then hollow out a spark plug, screw in a grease zerkin the hollowed sparkplug, insert in plug hole and fill a cylinder with a high piston with grease until the pressure rotates the crankshaft. which will turn the cam.Then remove the cam bolt.
                   In either case at this point you should be able to remove the head/ turn the crank by wrench / break it all down.
                                              Sounds like fun right? It's all fun and games ya know.

I did the atf and acetone thing for several days to no avail.I know the cam and chain have to be off. The engine will not turn even a mm.I was about to cut the chain off.Surely the engine will turn over, but if not I am back to square one.The head will never come off with a bolt still in it.The bolt is entirely loose.I assumed even if it was broken the loose part would just lift out.Most puzzling thing I have encountered with a bolt.usually they just snap and you are screwed, you try to drill and tap it out.I suppose a hack saw will cut the chain? I will let you know what happens.Thanks for the good input.
                                                                    RB

Offline rb550four

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Re: head bolt 79 650
« Reply #3 on: July 26, 2016, 02:04:06 PM »
Well, if you just cut the chain, your pistons will still be stuck to the cylinder walls. That's a whole other realm of WTF.
 There are ways to deal with that too, but they are all ball breakers, much easier to do the grease trick, save the frustration and proceed with the build.
« Last Edit: July 26, 2016, 04:30:37 PM by rb550four »
A few Honda 500's, a few Honda 550's, a few Honda 650's, '72 cb 450, a couple 500/550/650 hybrids, and 2001 750. 
  550 Snowbike -Somebody had to do it.
  http://forums.sohc4.net/index.php/topic,101678.0.html             
http://forums.sohc4.net/index.php/topic,137317.msg1550907.html#msg1550907

Offline crusierlover

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Re: head bolt 79 650
« Reply #4 on: July 26, 2016, 09:18:14 PM »
Well, if you just cut the chain, your pistons will still be stuck to the cylinder walls. That's a whole other realm of WTF.
 There are ways to deal with that too, but they are all ball breakers, much easier to do the grease trick, save the frustration and proceed with the build.

This whole deal is wtf so far.In 2 days I am off for 4 days.I am going to pull my other motor from my roling chassis,put itin this bike.Then someday figure out how to fix this motor.Hollowing out a sparkplug-how? Putting a grease zerk in it? How.Seems like it would take a lot of grease, would not make rings come loose except perhaps the piston I was using as a grease receptacle.Right or no? Also cutting the cam chain, it would drop down into the motor,making it mandatory to split the cases.however, with an engine as screwed as this one is that was probably going to happen anyway.No way a chain sitting for 23 years could be any good.At least not for long.One rev to 8000 rpm and kapow most likely.

Offline rb550four

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Re: head bolt 79 650
« Reply #5 on: July 27, 2016, 08:12:46 PM »
Old spark plug. wear glasses. start by breaking the porcelain and not damaging the threads.I set mine in a vice. and use a nail set and hammer. see the metal rod running down the length of the plug, that needs to come out, so does the rest of the porcelain. go to NAPA or equal and get the largest base greasezerk that will fit in the newly hollowed out spark plug. Put the base back in the vice and thread the grease zerk into the base nice and tight. Put the spark plug/ zerk in the head with the pistons in the highest position  in the cylinder either one of them. hookup your grease gun and let it have it. There should be movement soon.
There may be grease and allot of it if you haven't backed off the valves.or try the other cylinder. It's fast , it's easy ,this new tool is reuseable and will save you a hell of allot of time and effort.
 Make one and try it out.  The worse that could happen is not knowing what to do for the other 3 days you have off, right?
A few Honda 500's, a few Honda 550's, a few Honda 650's, '72 cb 450, a couple 500/550/650 hybrids, and 2001 750. 
  550 Snowbike -Somebody had to do it.
  http://forums.sohc4.net/index.php/topic,101678.0.html             
http://forums.sohc4.net/index.php/topic,137317.msg1550907.html#msg1550907

Offline crusierlover

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Re: head bolt 79 650
« Reply #6 on: July 28, 2016, 01:20:00 PM »
thanks.I guess its worth a try.