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  1. #21
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    Does anyone recognize this? Brass crank pin washers with a plastic washer/shim thing behind them?

    One of them was loose and moving around slightly. The other was pinned tightly in place.

    Aren't they normally a steel washer? It is grooved pretty badly where it meets the crank on both sides.





    Also, the pin is a single hole pin. Is it common to update these to 2 or 3?
    Attached Thumbnails Attached Thumbnails Washers.jpg  

  2. #22

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    The 6506 thrust washer is bronze (not brass). It was used from the early/mid '70s through the evo era. There should be no shim behind it. If the faces are worn, replace them. See the service manual. The roller retainers are what wear the washers out like that.

    Yes, most consider a 2 or 3 hole crankpin to be an improvement.

    Jim

  3. #23

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    Quote Originally Posted by Whoremonger View Post
    What percentages do you go for on a stock panhead ?
    Complicated question. The ORIGINAL generator motors that I have been able to "reverse engineer" in terms of balance were apparently balanced with a 50% factor. (That is common in V-8 car motors, I believe.) Those generator motors have a really wide and heavy left flywheel.
    For static balancing in the field, with today's higher highway speeds, I use 55% for 'most everything. But I could see using 50% on a pan motor with the really wide left flywheel, like HD apparently intended.
    I typed out a much longer answer because there is a lot to this balance stuff, but it was gettin' into da weeds, so I killed it and started over.

    Jim

  4. #24

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    Quote Originally Posted by confab View Post
    I've developed a fondness for Mr. Tatro Machine's YouTube channel. (HERE, if you are interested)

    In some of his videos he does flywheel balancing, and the way he does it is one half at a time with a bob weight. This seems to be the standard way.

    Is there some reason I can't just put both half's together, attach the weight around the crank pin and do it all in one move?

    I know just enough to be dangerous, so any information you have will be useful.

    As you can see from where this thread has gone, there are NO "silly balancing questions."

    Jim

  5. #25

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    Quote Originally Posted by JBinNC View Post
    Complicated question. The ORIGINAL generator motors that I have been able to "reverse engineer" in terms of balance were apparently balanced with a 50% factor. (That is common in V-8 car motors, I believe.) Those generator motors have a really wide and heavy left flywheel.
    For static balancing in the field, with today's higher highway speeds, I use 55% for 'most everything. But I could see using 50% on a pan motor with the really wide left flywheel, like HD apparently intended.
    I typed out a much longer answer because there is a lot to this balance stuff, but it was gettin' into da weeds, so I killed it and started over.

    Jim
    Thanks Jim

  6. #26
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    Thanks much..


    Perhaps that is some kind of compound he put back there, and it baked down and turned into a flexible "washer" looking thing?

  7. #27
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    Quote Originally Posted by SamHain View Post
    With a big enough press you donít have to stop at twin cam.
    True, but that large a press gets into the category of specialty equipment which isn't worth it to repair a stock crankshaft unless you already own the press (not cheap used or I'd have one for other reasons) or plan on doing them commercially. A home rebuilder will have a time finding a replacement rod kit since they aren't widely available at retail.

    Got any parts preferences for Twin Cam rod kits?.

  8. #28
    SamHain
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    Quote Originally Posted by farmall View Post
    Got any parts preferences for Twin Cam rod kits?.
    Nah, Iím not the brains behind that operation. Or owner of a twin cam.

  9. #29
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    Has anyone here tried the dynamic balance outfit in Indianapolis? Was told they were featured in EasyRiders back when they were a real biker rag instead of a yuppie rag.

  10. #30
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    Dynamic balancing is a complicated topic, But I wont build a vintage British twin without it. Static is just a ball park approximation and better than nothing. But Brit twins are extreme vibrators.

    Used to be a local guy when I was still involved with vintage Harley named "Lamb Machine" and virtually every shop and builder used him, and he balanced and set up the bottom ends, Usually people finished the rest of the build. We used to buy up blown up Ironheads and if not done right (Crank, cams and trannie) they predictably blew up shortly after, So we used Lamb to prevent that. My old partner knew how to set up the cams and trannies so we had that covered. I dont know who is doing this service anymore.

    But I have a guy I use for balancing and many shops use him for it and seen pans, knucks and shovels that were freakishly smooth all because of Ernie. (EV Lewis Dynamic balancing, Creswell Oregon) I have had Nortons that would shake your teeth fillings out and once balanced by him, felt like a Honda. Parts were no longer falling off, fenders stopped cracking and it was actually fun to ride again.

    To balance he wants ALL the parts that spin, including piston pins, clips, rings anything that attchs to the recip assy. First step is equalize weights (Vintage British pistons often vary by several grams, Ironically the asian made repops are spot on dimensionally and weight, however the pins often vary)

    I never tell him percentages I want, Although that is a popular topic on forums. Instead he wants to know HOW the engine mounts and what type of mounts, and then wants to know your riding style and RPMs. It is a night & day difference when done.
    He also will balance other parts and some people go to the extreme of gears and cams, even the timing gears. But Clutch baskets you might be surprised how out of balance they are. One part many overlook on a Brit bike is the Lucas type alternator rotor which is a very heavy lump that sits extreme outboard on the end of the crank. He usually charge 10-20 dollars for those and some only need a few dimples, others look like a cheese grater on one side.

    Usually weight removal is all thats needed to balance, but *SOMETIMES* it isnt, And thats when things get complicated. Whats then done is machine or weld on Mallory Metal, a special high density metal to get the weight needed to balance. On a few cranks you can see holes machined into the side of the crank cheek and the mallory added and tack welded in. This is common half cheek cranks where there is no material on the other side. A full cheek wheel is easier to balance.

    I asked Ernie about his machinery, And while you can purchase super duper digital dynamic balancing machinery, Many of these guys build their own, which is a special skill set. That and the brains and tribal knowledge to know what you are doing. I am very worried about Ernie as he is an older guy, and he wont be around forever. I know guys who send stuff out to other shops and the results vary from excellent to horrible. A good balancing guy is hard to find. But Ernie does the bike stuff on the side, not enough out there to live on. His bread and butter is Industrial machinery where an out of balance condition is not acceptable, He also does airplane propellers where an out of balance condition is REALLY unacceptable.

    Here is a video of a specialty crank we made for a Norton Land Speed record bike, Eddy built the crank himself using 2 other cranks I gave him, cut them apart and rephased them into a 270 degree setup. The reason is the same as Ducati and modern Norton 961s, It partially cancels out vibration at higher RPMs. The race bike was built to run 11,000 RPM which a normal Norton twin will never do, (Std main bearings are only rated to 8,000 rpm so not your typical build)

    See: https://www.youtube.com/watch?v=0F8nBxvlW3s Thats Ernie talking on the video. As I said, this skill to me is an artform.

    Now... Rocking couple, which is a serious problem, is a topic in itself. Static balancing will never ever catch rocking couple, Thats why Dynamic balancing is the only acceptable method. In laymens terms its easiest to just say its a weight wobble that manifests at certain frequencies and RPMs. Change some small details and it moves around. But Nortons have horrible problems with Rocking couple and WHY I use Ernie, He fixes it.

    You can get into Primary and secondary forces and Rocking couple as well, It get incredibly complicated. This is probably one of the best indept explanations directly related to Motorcycles.
    See: https://motochassis.com/Articles/Eng...ineBalance.pdf

    I know a German guy who gets a lot of press about his motorcycle hobby shop called "Moto Galore" hipster magazines love him. Totally cool guy. He is an engineer by trade and specializes in vibration analysis for industrial applications and earns enough working at that it funds quite well his passion which is vintage Harleys and Brit bikes. Vibration is no joke.

    Here is why, Before computer modeling and finite analysis, Boeing built some planes that passed all testing but in use the wings fractured and fell off, It was because fully loaded with passengers and certain operating conditions not revealed in testing vibration set in that fractured the airplanes wing roots, Many people died before they figured it out. The fix? Change the length of the props and RPMs of the engine in certain conditions. The same applies to motorcycle engines. By design there is certain things you cannot change, But you can move things around a bit to make it livable.

    This guy wrote a manual on Norton racing, and makes some awesome products to address the inherent problems but this technique is valid for any make and model, (It measures fore and aft, and vertical, not rocking couple but still useful)

    " The way to determine the best balance factor is to use a scratch tool - sharpen a wire or thin shaft to a needle point and mount it to a heavy weight on a stand (if you want to get fancy you can have the wire slide in and out of a heavy tube in a precise manner). Securely tape a piece of polished sheet metal to the middle of the timing cover. Rev your bike to 4000 or 6000 RPM or wherever you want to check it. LIGHTLY AND MOMENTARILY touch the needle point to the polished sheet metal (this takes practice - use a helper to tap the sliding needle point or try tilting the running bike MOMENTARILY into the scratch tool). Repeat in several different places to get a data base. Look at the scratch marks under a microscope. It will probably be an oval shape.

    If the oval is stretched front to rear then the balance factor is too high. If its stretched top to bottom then the balance factor is to low. Everything else is just guesswork. If you error then error as little as possible on the high side. Always calculate in "wet" specs (oil in crank). Tell us what you find.

    There is no perfect balance to keep an Atlas from buzzing your brains out because the Norton twin is inherently out of balance somewhere throughout its crank rotation. The only solution is to solve the problem at its source and reduce the reciprocating weight (pistons, pins, small end of rod)."

  11. #31

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    Quote Originally Posted by confab View Post
    Looks like you practically have to be a machinist to own a Harley and work on it yourself?...
    I have a bunch of 'specialty' tools from working on old Lister engines... use them on my Sporties because it's the same era of technology.

  12. #32

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    Doug,
    Good discussion. That is what I was hoping for.

    Note that there is no rocking couple when dealing with HD and vintage Indian motors, because the piston & rod assemblies run in the same plane. That is the main reason the static balancing method works so well for these motors.

    Jim

  13. #33
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    Much good info here on this topic-

    Might be of interest to some of you all..

    http://www.caimag.com/wordpress/2011...6-how-i-do-it/

  14. #34
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    Quote Originally Posted by JBinNC View Post
    Doug,
    Good discussion. That is what I was hoping for.

    Note that there is no rocking couple when dealing with HD and vintage Indian motors, because the piston & rod assemblies run in the same plane. That is the main reason the static balancing method works so well for these motors.

    Jim
    JB, Agreed & thanks, but as far as Rocking couple goes,,, its at least best to have an understanding as well as the primary & secondary forces, as well as WHY the HD and Indian engines are designed they way they are, which was brilliant in a way, but very limiting in others. I dont need to be a leading engineering expert on this, But I try to educate people on it because I get tired of people knocking these old bikes for problems that with a little effort and research all can be fixed or addressed.

    I know a lot of people who would never own a vintage Harley because of the reputation, But I can point to some old pans and knucks I know of, and while,, NO! aint no way some stranger is getting a test ride, But DAMN they are smooth and reliable. So much for myths eh?? If you know who to ask,, you will find out some ace like my guy locally set them up correctly.

    When i was still running my shop I had a mid 60s Norton in a featherbed frame, These are famous vibrators. If I had a customer talking about a rebuild I let them take it for a ride. Many said it rode like a Honda so it wasnt hard to sell them my services and WHY it cost more.

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