I messed up balancing a crank, what can I do?

[Nickt919]

This thread reminds me of why I like Hondas.

Or… Yamahas

 

[DAMIEN1307]

Or… Yamahas

Or even Suzuki's and Kawi's

 

[GW's Motorized]

Or even Suzuki's and Kawi's

Or a suzuki engine in a honda...

(Will explain soon )

 

[Al Regresar]

Or a suzuki engine in a honda...

(Will explain soon )

Hello, I had an RM 125 and it rocked!

 

[GW's Motorized]

Hello, I had an RM 125 and it rocked!

It's gonna be a ts125 in my ct90 . I have the engine on order and I'm actually doing the body work and touching up the paint right now

 

[ImpulseRocket]

The first time I balanced a crank I drilled my center hole so deep I just barely poked out the other side on both sides because I set my depth wrong. Still balanced out great, and I still ran it. Never had a problem.

Worst case scenario if you run it, the balance is off and it runs a bit less smooth. At that point the option is the same as.if you were to give up - buy a new crank and start over.

Heck, for all you know this will be the best balanced crank you will ever make lol.

 

[francisjohn]

Precise and accurate work is obviously best… But…

You’d be surprised at what will still run and run well.

I post this pic below in a thread yesterday. A rod bearing cage came apart and went thru the engine. The piston kit was very new so I cleaned everything up and I’m still running it today. I just changed the piston ring and ran the new ring for the first time yesterday. It still runs like a champ.

The piston top and head were the only things damaged when bearing failed though…
Had either the piston skirts or cylinder gotten scarred I would not have run it again.
The cylinder and piston skirts were fine.

This happened to me. It was with my LD90 top end. I didn't even know it happened, and couldn't tell you the time between it happening and me noticing. I lifted the head up to say hello to the piston and noticed there were chunks missing out of the piston and out of my head. Upon breaking down the engine, I found that on the upper wrist pin needle bearing, one of the needles, about 1/5 of a needle broke off, the rest of the needle fell out of the cage when it was in my hand.

The first time I balanced a crank I drilled my center hole so deep I just barely poked out the other side on both sides because I set my depth wrong. Still balanced out great, and I still ran it. Never had a problem.

Worst case scenario if you run it, the balance is off and it runs a bit less smooth. At that point the option is the same as.if you were to give up - buy a new crank and start over.

Heck, for all you know this will be the best balanced crank you will ever make lol.

The center hole, I was told to drill before it pokes out on the other side, but I found this out after. I begun the balancing eight months ago. When I drilled the first center hole, I thought I drill straight through. I then realized the conrod would get in the way, and then figured out to not break through.

I installed the crank yesterday. I never rode a balanced crank before and the balancing I did wasn't the best. The vibration reduction is very noticeable. I couldn't tell you what the original balance factor was, or what it is.

Eight months ago, I did what I seen everyone else do with x3 holes on each side. I didn't understand that every crank for the most part will have a different balance factor, and the diameter and depth you drill is based on current balance factor and where you want to be. It reminds me of porting. People think porting is removing 1mm from each port, not realizing to find your current port map, figure out where you want to get to and remove material based on that.

What would I have done different before I started drilling into this eight months ago? Find my current balance factor, and figure out where I want to be.