If you were to replace the conrod on a crank, say with a kit like this: https://www.1977mopeds.com/product/984/Derbi-Metrakit-Conrod/, where would you go to have it done? I understand the alignment has to be really perfect so its risky to do it yourself. I know the local motorcycle shops would be dicks or tell me it'd cost $200 if I ask them.
any reasonable machine sho with a hydraulic H frame press
I too have been wondering how difficult it would be if one had access to a press.
No BIKER style mc shops..
I would go to a dirtbike rebuilter/atv... shop you know what I mean?
There is a small shop here out of town on a farm..
I had them do you have to make a jig.. to hold the flywheels and then you can press the pin with 20 ton.. maybe.
I pay my machinest $50 to press and old rod out press a new one in & balance the crank. I have pressed em out before but would never try to press a new one in let alone balance it, I have access to the tools and even then.. It's worth it to me to know it's done correctly
I just use my thumbs .
Not every machine shop has a truing stand to align in the wheels. You don't spin balance a crank after you split a crank, but truing it does bring it back to balance, if you didn't you'd definitely feel it shake.
A good machinist can break it and re-assemble it on his 20 ton press, and true it on lathe centers w/ dial indicators. But they are pretty reluctant to knock the wheels into alignment on their lathe. Otherwise, you'll have to find a motorcycle shop that does it and pay the price.
Nowadays, it's probably just as cheap to buy a complete new crank assembly. The old school art of building motors seems to be going by the wayside with all of the foreign parts and all.
Except when a whole new performance crank for a certain bike isn't for sale anywhere, in this case.
I haven't used these guys but it might be worth looking into. http://www.rb-designs.com/crankshaft.html
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