Crap!!!

thomas@hauge.net

thomas@hauge.net

Senior member
Location
Gothenbourg, Sweden
For the latest year I've been trying to fix up up the crank for my 500 project.
I got around and got a set of Carillos form Wolfgang.
Then the workshop told me I needed another crank, some parts of where useless.
I got my hand on another crank in nice used condition thanks to this forum, wich was sendt to the workshop.
The guy with the workshop has been in the buisiness since Jesus weared shorts. Hes been doing mostly all the Laverda cranks in Sweden since tehy where sold and hes used by many workshop for specialworks.
Now to the issue:
The guy does only the job you ask, nothing more, nothing less.
My mind was so busy with all the machining on the rods (thanks for all the tips) so I forgott about rebalancing.
I found out yesterday when I found the new pistons in a box and thought -"why are not these pistons with the crank to be balanced?"

So here I am with a new rebuildt, unbalaced crank.

Just have pack it with the pistons and send it back??

It will set me back another 3-4 month as the job in line is quite long.
 
Thomas,

Why bother?

The 500 has 180? crank throws, these effectively cancel themselves out, no matter (within limits, of course) how much weight you attach to the conrods.  A couple of grams up or down isn't going to make any difference.  The factory certainly did not bother re-balancing Formula cranks when forged pistons were fitted in place of the cast originals.

I'd be concerned about getting the pistons' weights equal, stuff it all together and you're good to go!

piet
 
Hi thomas - agree with Piet  - when we've done 600 conversions etc - never rebalanced crank - vibes were no worse or better than standard - Regards - Phil
 
We fitted pistons to my Atlas motor which were totally different to standard pistons, as Piet suggests we made sure the weight of the pistons was equal but  never bothered having anything balanced, in fact we threw the balance shaft in the bin.
The motor runs fine with no excessive vibration.
 
Hi Thomas,

The only time you need to send the pistons away with the crank etc for balancing is when you are changing the actual "balance factor" or the company is equalising the piston and rod weights for you.
Measure them and make sure they are within 4g of each other and all will be OK.  If you can get them to 1g or zero then even better but unless racing you are wasting your time.

Good luck,
Julian
 
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