Panhead rebuild project...

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Patio
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Panhead rebuild project...

Post by Patio » Thu Jul 30, 2015 4:22 pm

My gal of many years bought me a motorcycle that I really liked. It belonged to a friend that is losing his eyesight. He is about retirement age and has another bike to ride, so he sold this one. He has owned this bike since 1973. The motor has been in a couple of different frames and has been painted 13 different colors. This bike has won many trophies over the years.
20150418_103150a.jpg
The bike is a 1962 Harley Davidson motor in a 1948 HD frame. The motor has a knock in it. I don't know how bad of a problem it is yet. I have taken the push rod covers off and the push rods seem to be adjusted properly, which means the problem is most likely in the bottom end. That is not good news, as I will need to pull the motor from the bike and totally dis assemble it. The motor had just been rebuilt by another friend that is no longer with us. It was said he took it for a ride after the rebuild and got on it a little to hard, creating the knock. This means I should only need to fix that which is now broken and everything else should be good to go. We shall see as the project goes.
The motor is just one of the issues, but the one I am going to tackle first. The poor front end geometry is another that I intend to correct once it is running.
This is likely to take some time to do. I am going to do some work on the shop in preparation for the project. I will post here as things move along.

Wish me luck, I think I will need some. :)
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Metalman
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Re: Panhead rebuild project...

Post by Metalman » Thu Jul 30, 2015 9:48 pm

Nice bike. I'll put my bet on the knock coming from the rod pin/ roller bearings at the bottom of the rods. I could be wrong. If I remember it right that pin gets oiled through the pinion shaft at the cam cover once every 360 degrees of rotation.
Back in that era lots of the necks were cut, raked out and welded up along with extended forks. No thought to what happened to the handling. The result was usually excessive trail which made low speed handling heavy with the front end wanting to flop to either side.
Enjoy the project keep us posted.
Ernie F.

Patio
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Re: Panhead rebuild project...

Post by Patio » Thu Jul 30, 2015 10:43 pm

Hi Ernie, yes the trail is way out on this bike. I have ridden this bike around the block and the front end is very heavy worse than my other chopper. I believe the frame neck is uncut and that the fork tubes are just extended. I have not done any measuring or pulled any covers yet that will be the next thing to do once I get started.
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JackF
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Re: Panhead rebuild project...

Post by JackF » Sat Aug 01, 2015 6:19 pm

Looks like another nice project. Hopefully not as long or involved as the last one.


Jack

spro
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Re: Panhead rebuild project...

Post by spro » Wed Aug 19, 2015 1:08 pm

I spoke with a friend who has a 1957 Sportster. He had a similar situation and dug into it thinking a rod bearing. He found the piston was cracked at the pin.

Big Rack
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Re: Panhead rebuild project...

Post by Big Rack » Tue Jan 26, 2016 12:14 pm

You can verify lower end knock by tightening the primary chain way hard like tapping the trans. back with a 2 x 4 and hammer. It takes excess play out and quiets the motor, obviously not a solution but it will show the problem. You'd be surprised how many old bikes used to be sold like this.
Chances are if rebuilt it was just the top end, crankshaft is four pieces and all must be properly aligned to assembe. I wouold suggest have a well experienced Harley mechanic set up the crank, it also may be better in the long run to purchase a new set of rods and crankpin I found a new set from S&S wasn't much more than having mine rebuilt with a lot less waiting. Of course that was 30 yers ago.

Patio
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Re: Panhead rebuild project...

Post by Patio » Tue Jan 26, 2016 10:25 pm

Big rack, that is an interesting procedure. I assume it helps one to figure out if it is the upper or lower end?
I intend to pull the motor and go through it. The motor had just been rebuilt by another friend, that has since passed on. I have knowledge of the motors history back to about 1973. I know that the flywheels are original and have some 30 holes drilled in them. It happened when a couple of guys stayed up to long, doing the rebuild. They were in the process of balancing the flywheels and kept drilling the wrong places, so they started over and got it wrong again. This went on through the evening. :shock: I am going to see what condition things really are in, and make a plan from there. I may fill all the holes with lead and create a set of heavy flywheels, for torque.

I just finished rebuilding a 1974 sportster that had issues with the tapers in the flywheels. If your interested, you can view that post here.
http://www.chaski.org/homemachinist/vie ... 26&t=92831

This will be my first time into a Panhead, so I have a bit to learn, and will take all the knowledge I can get. Thanks for replying to the post.
I acquired a new to me lathe and have spent many hours getting it into shape. I am close to starting on the Panhead, cause if I don't start soon, I will not be riding it this summer. :)
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Patio
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Re: Panhead rebuild project...

Post by Patio » Sun Feb 14, 2016 10:53 pm

It has started!

Step 1, pull the motor.
20160214_152238a.jpg
check!
20160214_152249a.jpg
Move frame so table is empty for motor autopsy. Looking for the cause of a knock.

More to come!
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Patio
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Re: Panhead rebuild project...

Post by Patio » Wed Feb 17, 2016 1:45 am

Progress continues....
20160216_210005a.jpg
20160216_210026a.jpg
So far, no smoking gun!
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Metalman
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Re: Panhead rebuild project...

Post by Metalman » Wed Feb 17, 2016 9:12 am

Let us know what you find. Looks like you have a later style oil pump. I have a 1967 Shovel Head, bottom end is the same I believe. I plan to split the cases and have the bottom end gone thru. I'm told years back some would run the 2 lighter sides of the flywheels, quicker revs-rpms at a loss of torque. I guess if the bike is all stripped down and lighter they responded, the loss of torque didn't hurt and they were faster. I don't need to get involved with any of that, if I wanted to race I wouldn't do it with one of these old motors. Too rare and costly to explode!
Ernie F.

Patio
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Re: Panhead rebuild project...

Post by Patio » Wed Feb 17, 2016 10:56 am

Ernie, I am not expert on these motors, I learn as I go, as it is with most things. The past owner has told me the oil pump is from a Shovel engine. Good eye!
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Metalman
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Re: Panhead rebuild project...

Post by Metalman » Wed Feb 17, 2016 11:11 am

I'm no expert either. I have someone around here that has the tools, knowledge and does good work on these while being reasonable.
Here is a link to a frame plan with dimensions that you may find useful: http://www.shovelhead.us/pics/sheets/1948-frame.pdf I had this printed a large size to make it easier to read but can't find it.
Ernie F.

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