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Have a 46 FL with a shovel top end. Its in a weld on hard tail frame. Pan or shovel? I dont know. Im looking for a knuckle top end. Will it fit in my frame?? Are the rods the same? Will the knuckle pistons and pins work? Can I switch without opening the lower end? Are shovel cylinders bottom bolt pattern the same as knuckles? This was a common thing back in the day to put shovel tops on pans and knuckles.So my questions are for the old timers! The bike is probably done just the way it was most commonly done back in the day. Anybody out there ever put a shovel top on a pan or knuckle? If so,Would you please tell me what you had to do to get it done?? Thank you for any help!!
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Your knuckelhead should fit in your frame with no problem. Back in the Day {old timers as you put it,ha,ha] put shovel and pan motors in knuckle frames and had to modify the seat post to fit the motor in the frame. If you have a shovel in it now you will have no problem getting a knuckle in it.
More than likely you have Knuckle flywheels ,rod fit from 41-73 before they changed. Pistons are the same from 41-79.
Bolt pattern is the same for the cylinders.
I've done a shovel top on a pan and all you do is put the sovel top on and make sure you have an external feed line for your shovel top.
If I can be of anymore help e-mail me -
THANKS!!
What a great and complete answer! Thank you for taking the time. Now I have a pretty good idea as to what's going on with my bike. Now its all about the search for the elusive, affordable,usable knucklehead top end!!! Thanks again.Comment
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You're welcome.
I'm trying to restore a 47 Knuckle that a friend of mine road as a chopper back in the 70's. I know what you mean a hard to find and don't forget expensive.
Talk to you later
George AllenComment
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I have a 38 EL motor in a panhead swingarm frame with the weld on hardtail.
Two things I had to do.
Notch the down tube to clear the rear exhaust tin. This eliminates the ability to use a pogo seat.
Also needs a thick spacer on the front motor mount.
I will try to send a couple of pics.Comment
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pic of spacerComment
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Thanks!! I do have a pogo seat on it now but if I have notch it out I will just run a different seat. Good luck with your bike,sounds nice. Thanks for the answer and the pictures!! RonComment
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If you can find a copy of What Fits What on Harley Davidson Motorcycles by Mike Armanan Kurt Heinrichs it will also help you with a lot of your questions. The book is out of publication but I have seen it on ebay in the past. They talk about the differant frames, what you have to do to fit engines into them.
Pretty good book
George AllenComment
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Thanks Again!
Actually Ive had that book for years. They dont go into the swingarm frames like mine once was. but your right, it has some great info. I still like your answer better! Ive been thinking about the lifter situation.I will need knuckle blocks, Im sure. How about the lifters? Do you think knuckle lifters will drop right in? THANKS AGAIN!! RonComment
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I have put several knuckle motors in pan frames and NEVER had to modify the seat tube. I always try to find a way to do something without changing original parts. Aftermarket frame, go for it! The front engine spacer was a factory part in '48. Part # is 438-48. It was stock on '48 ULs since they originaly were configured for knuckle frames. The pan front mount is approximately 3/8 in lower than a knuckle/ul mount. If the engine is mounted without the spacer it is possible to break the cases in a big way! Mixing knuckle top ends on pan lowers or vice versa is a challengs as the cam lobe shape and spacing is different. The rocker arm ratio is also different so the cam must match the top end or major problems occur. Best to keep the species intact. That said I have seen knuckle pans, pan knuckles, shovel knuckles, knuckle shovels, ul shovels and every other bastard combination in between. RobbieComment
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Robbie
I quess I should have been a little more clear since you have accused me of butchering original parts.
This is a swing arm frame that was converted with a weld on hardtail kit long before it came into my possession. So forgive me if I notched the down tube.Comment
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Sorry to make it appear as an acusation, that wasn't my intent. I just wanted to point out that it could be done with no mods. Believe me, I am as guilty as anyone for modifying stock parts since I spent my early days buiding choppers in the early '70's. I think my need to protect stock parts is trying to absolve myself. I also believe all bikes should be ridden and that in itself creates a dilemma. Modify to make it possible to use, or keep it stock and off the road? I say whatever it takes to use it. RobbieComment
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i thought knuckle and shovel had the same ratio.Originally posted by Rub
Mixing knuckle top ends on pan lowers or vice versa is a challengs as the cam lobe shape and spacing is different. The rocker arm ratio is also different so the cam must match the top end or major problems occur. Best to keep the species intact. Robbie
I could be wrong...never did much mix-and-match...Comment
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Pans and shovels are the same ratio, close to 1 1/2 to 1, knuckles are different, 1 to1. It all gets complicated because lifter blocks are specific to top ends as well as pushrods, and right side cases are specific to lifter blocks. It is not just a bolt up conversion. There used to be a bike around that was built with one each panhead and knucklehead. It was a wild looking thing but I'm not sure how well it ran. Some of the old cam makers would grind special cams for odd stuff like two front heads, shovel heads on sportsters, etc. Don't think anyone does it anymore but I'm not sure of it. Anyone know?
RobbieComment
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