Jump to content
Sign in to follow this  

Crank Balancing

Recommended Posts

I've searched the forums and I can't find a definite answer. If one buys a brand new Hot Rods Crank and builds a big bore 250F with it, does said crank need to be balanced?

Would it be a better option to rebuild the stock crank with a new rod?

Share this post


Link to post
Share on other sites

Many people did install their new crank directly into their cases, IMO is i was to spend cash to rebuild my motor i would pay the extra 50-100$ to make sure the crank is straight.

Share this post


Link to post
Share on other sites

Thanks. Next question: Would it be ok to let a local race car/hot rod shop balance the crank? I assume balancing a motorcycle crank would be the same concept as balancing a race car crank right?

Share this post


Link to post
Share on other sites

Straight does not mean blaanced.

Most cranks are blaanced for an average stock weight piston. If you had a cast stock piston and go for a forged, there is a significant weight difference and unless you get the crank balanced, you will get more vibes.

Keep in mind, a thumper wil always vibrate. All you can do is reduce it and deal witn the harmonics. I am no expert on this but I have gone through it. typcally, with a single, they use a 'balance factor' in the neighborhood of 55~65%.

Share this post


Link to post
Share on other sites

A single cylinder crank cannot be balanced per se. All you can do is move around the imbalance into rpm ranges that are not used often, or less destructive.

Personally, I would never bring a motorcycle crank to a auto mechanic/hop up shop. They won't have the proper knowledge of how to get the best balance for your exact application like a dedicated motorcycle race motor builder would.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...