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Discussion Starter · #1 ·
I replaced the bushings for the piston pins in shovelhead.
I need to have them reamed for the piston pin to go in.
Is there some way I could do this without having to load the bike up and take it to shop? Or would that be my best bet? (take to shop)
Thanks for the input.
 

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pf317 said:
I replaced the bushings for the piston pins in shovelhead.
I need to have them reamed for the piston pin to go in.
Is there some way I could do this without having to load the bike up and take it to shop? Or would that be my best bet? (take to shop)
Thanks for the input.

JIMS makes a tool that will permit the reamer to go straight into the connecting rod bushing. I would not recommend doing this job freehand since it really is critical. Maybe you could rent or borrow the jig and reamer.

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Dont forget to use the squaring plate and flat bottom test piston to true the rods.
As the nature of the multipiece crankshaft doesnt garrantee the rods will be true even using a reaming fixture.
The rod trueing procedure is shown in early HD manuals.
 

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L.Linkert said:
Dont forget to use the squaring plate and flat bottom test piston to true the rods.
As the nature of the multipiece crankshaft doesnt garrantee the rods will be true even using a reaming fixture.
The rod trueing procedure is shown in early HD manuals.

Good point! The fact that the small end bushings are in need of replacement might be an indication that the rods should be checked in any case. They can be rather fragile under tough circumstances. I've seen them bend with a few good backfires.
 

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Yes, those old mallable iron rods bend very easily. And I was thinking the same thing about an underlying problem causing the wristpin bushings to need replacement.
 

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L.Linkert said:
Yes, those old mallable iron rods bend very easily. And I was thinking the same thing about an underlying problem causing the wristpin bushings to need replacement.

Once, many years ago I was in an enduro on my Harley 45". There was a river crossing at the Des Plaines river in Illinois and I must have got off track. I ran the bike under water up over the carburetor and it got some water and stopped running, abruptly.

When I got it out of the river, the cylinders were part full of water and after removing the spark plugs and cranking a bit and blowing out the magneto it finally started. The oil had turned completely white with a little foam so I knew I was in trouble.

When I got it home, I pulled the engine and found that both connecting rods were bent slightly sideways, cocking the pistons over to one side when the cylinders were removed. Fortunately I had another engine so I substituted flywheels and later fixed the other crank by replacing the rods.

It sure didn't take much. Ha.

:)
 

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L.Linkert said:
That sounds like a fun day anyway!

Was it ever. I've also seen Knuckleheads run under water in enduros and turkey runs. Those didn't do well since the combustion chamber was much tighter than the flatheads. They would crack cylinders and actually lift the cylinder out of the mouth of the crankcase. That's bad.

That's one reason that there are so few Knuckleheads and Panheads left. Many of them were ridden in Enduros and TT races. Lots of them were used in the brush with sidecars and such. Not much left after a number of 500 mile runs.

Lots of the rest of them were chopped, blued, screwed and tattooed. That's why a clean, original Knucklehead or panhead frame would be worth so much nowadays,. I saw a nice one last year. It looked like about a 1946. $2,500 for the frame alone.

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Back in those days the roads were bad in my area!
Speaking of old knuck frames, I just got one from a barn. Its pretty good, but the lower rails are banged in as is typical from the times and it looks a little tweaked.
 

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L.Linkert said:
Back in those days the roads were bad in my area!
Speaking of old knuck frames, I just got one from a barn. Its pretty good, but the lower rails are banged in as is typical from the times and it looks a little tweaked.

You were lucky. With some nice TIG welding and a trip to a frame shop, you will have a gem.

I would like to build a civilian style Harley 45 but I've been looking for a frame for years and every last one I've seen has been raked. I did see a semi-complete bike in baskets at a swap meet last June but the proud owner wanted $5,000 for the pieces and, although the frame was OK, the front forks were off a UJM bike. Ha. Those OEM forks are expensive if you can find them also. I figured it needed at least another $5,000 in parts so I just walked away.


:unsure:
 

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Discussion Starter · #11 ·
Couldn't you take the rake out of the frame and get it back to the original position? Just some reworking of the rework so to speak. A little welding and fitting.
 

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pf317 said:
Couldn't you take the rake out of the frame and get it back to the original position? Just some reworking of the rework so to speak. A little welding and fitting.

Oh, I guess you could. The only problem is that it would probably not look exactly correct. Some people have done so but it seems that the repairs are detectable.

The other parts are hard to come by under the best circumstances and it always seemed to me that I could live with a lot of other things if I had a nice original frame. It's sort of a sticking point.

V-Twin Company has re-pop frames that look very authentic for 45's, UL flatheads, knuckleheads and panheads but I'm sure they're made in China. That wouldn't do for me even if it looked right. They're not cheap, either.

If I ever find a good OEM frame and forks I'll probably buy them.
 

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conn rod bushing reamer

These bushings Must be reamed straight. Jims Machining sells the tool to do this. Your final size should be around .791", if you dont have the tools and/or have never done this, (TAKE IT TO SOMEONE!!) if not, you could have a piston running cocked in a cylinder !!!!!!!!!!!! belive me, you dont want this.. Do it right or you WILL be sitting on the side of the road............
 

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dynoman10 said:
These bushings Must be reamed straight. Jims Machining sells the tool to do this. Your final size should be around .791", if you dont have the tools and/or have never done this, (TAKE IT TO SOMEONE!!) if not, you could have a piston running cocked in a cylinder !!!!!!!!!!!! belive me, you dont want this.. Do it right or you WILL be sitting on the side of the road............

I'll go one step farther. I wouldn't even attempt this with the rods in the engine. The best way to do it would be on a Sunnen hone or equivalent with a proper jig. Whatever size they are, they must be fitted to the proper clearance through full length of the bushing with no scores or high places. If not, the result will likely be premature failure and knocking and oil burning, etc.

In fact, that job is so very critical that it's almost worth replacing the lower end if you need it since I think the rollers would probably be ready for a survey when the upper bushings get bad. JMO.
 

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From my experience, upper bushing failure relates to other crankshaft problems anyway.
Especially on older crank shafts that have abit of error in the manufacture of the components, there is no garrenty that the rods will in effect be straight with the cylinders even if the rod bushings are trued in a fixture before assembly and then the crank assembly trued. This is because the crank pin can end up a little cocked.
That is why the squaring plate and flat bottom test piston is used, as shown in the old HD manuals.
Components such as the precision Jims flywheels are a different story.
 

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L.Linkert said:
From my experience, upper bushing failure relates to other crankshaft problems anyway.
Especially on older crank shafts that have abit of error in the manufacture of the components, there is no garrenty that the rods will in effect be straight with the cylinders even if the rod bushings are trued in a fixture before assembly and then the crank assembly trued. This is because the crank pin can end up a little cocked.
That is why the squaring plate and flat bottom test piston is used, as shown in the old HD manuals.
Components such as the precision Jims flywheels are a different story.

Yep, that's right. Generally those small end bushings are the last thing to go. If they need replacement, probably so do the rod rollers and the flywheel side clearance washers. I would also suspect the rod alignment.

When I got my shovelhead about 15 years ago, the flywheels where shot, including the side washers, the small end bushings and even the flywheel exteriors looked like they had been beaten with a steel hammer. The left flywheel taper was terrible also.

I replaced it with a commonized crank balanced as a replacement for the shovelhead. It came from the motor company in a box and at $495 was less expensive than anything else that I could have done. It is very smooth also. All new parts with less than .001 runout.
 

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The flywheel thrust washers are an indicator of whats up.
Worn on one side, bent rods. Worn both sides twisted rods. Or a combination of the two.
It also relates to the multiple piece crankshaft and the alignment of the various components, where a condition can exist that the rods are true to themselves but not true to the cylinders.
 
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