a buddy says i need to take my bottom end to a motorcycle machine shop and have it balanced after installing a new crank and rods.

i havent had much experience with motorcycle bottom ends. is it true?

also, how much should i be looking to pay?

Yup thats what you need to do, NRHS has some prices listed...

http://www.nrhsperformance.com/svbalancing.shtml

ok so heres another question. if i were to buy a crank and rods already assembled, used perhaps. would i need to balance?

If you got a crank and rods that were sold as a set and pre-assembled, so to speak, the balancing will have already been done. Most, if not all (aftermarket) sets come pre-balanced and will say so.

If you got a crank and rods that were sold as a set and pre-assembled, so to speak, the balancing will have already been done. Most, if not all sets come pre-balanced and will say so.

im just trying to crunch numbers and possibly pinch pennies with this rebuild. id hate to have to shell out too much money cause i really dont have all that much

i did find this on ebay though which got my gears turning
Item number: 270335528992

$350 or make an offer...if i had to pay ~$300 for rods then pay to have it all balanced this could be a cheaper alternative

Your buddy doesn't know what he's talking about. The wheels came from the factory with the standard balancing done those days on those engines. If your wanted to "improve" on that then you would balance the wheels at a shop....

Your buddy doesn't know what he's talking about. The wheels came from the factory with the standard balancing done those days on those engines. If your wanted to "improve" on that then you would balance the wheels at a shop....

i called a motorcycle machine shop today and they said if you dont balance the crank and rods for a buell it can fry the race and cause havoc after higher rpm's.

the shop said its only $75 to have it done so i might just do it anyhow just to be sure. id hate to have anything happen after having to buy everything again

im not sure, just kinda trying to talk it out. i believe you though

This is an extract from The Sportster Performance Handbook;

The standard crankshaft balance factor as it comes from the factory is 62%. For high speed use, many tuners prefer to change this factor. Asking six different tuners, a factor of around 55-60% is preferred.
You have to take into consideration, the weight of the reciprocating piston and the rotating con rods. When these weights are changed by using larger, heavier pistons, the balance factor of the crankshaft is changed. Not necessarily a problem. After converting an 883 to a 1200, you may find that you like the vibration characteristics better. If not, you can dismantle the engine and send the crank and piston assemblies to a speed shop for precision balancing.

This is an extract from The Sportster Performance Handbook;

The standard crankshaft balance factor as it comes from the factory is 62%. For high speed use, many tuners prefer to change this factor. Asking six different tuners, a factor of around 55-60% is preferred.
You have to take into consideration, the weight of the reciprocating piston and the rotating con rods. When these weights are changed by using larger, heavier pistons, the balance factor of the crankshaft is changed. Not necessarily a problem. After converting an 883 to a 1200, you may find that you like the vibration characteristics better. If not, you can dismantle the engine and send the crank and piston assemblies to a speed shop for precision balancing.

thanks for that. this is a 1250cc motor for my buell which is gonna be seeing a lot of higher rpm's so id like to rest assured my crank is balanced proper.

you just gave me piece of mind. like i said previously, the shop only charges $75 and its not like i have to tear down the engine to get at it since its still in pieces haha