Crank Balance and weld

[Guest]

The 1150 crank isn't really "welded", it has spot welds on it to keep the throws from shifting. When you get a Falicon or comparable job done they weld completely around the join between the throws and the crank pins. The older GS motors didn't even have that. I still think making sure you have enough clean oil that doesn't get too hot is the real problem with this and most oil cooled motors. I sure would like just a little less "buzz in the bars" though, since my 1150 is so supple in other rev ranges.

I don't like to talk bad about a company but I would not take a lawn mower crank to Falcon.
APE or Gardner the only places to go

 

[rapidray]

For roller bearing cranks, the ONLY places I will send one is to John Pearson in Ohio, Stan Gardner in Maine, or Bob Mosher in Florida. I wouldn't ask Falicon what time of day it is!
Ray.

 

[blowerbike]

+1 on Pearson...not that i'm partial or anything

 

[madmikeracing]

Hi Was reading these older posts and had to reply, Many Years ago honda 750 crank hacksawed the **** out of it smoothed it sanded it back together with gs liners pistons yamaha rods it didnt vibrate bad at all ,That started making me wonder about all this balancing hooplah. I think people read to much ****e on the internet and magazine articles and take it all to heart, so much bull.... out there Mike

 

[storm 64]

Hi Was reading these older posts and had to reply, Many Years ago honda 750 crank hacksawed the **** out of it smoothed it sanded it back together with gs liners pistons yamaha rods it didnt vibrate bad at all ,That started making me wonder about all this balancing hooplah. I think people read to much ****e on the internet and magazine articles and take it all to heart, so much bull.... out there Mike

Maybe true, but some people like to do things right.

 

[Nessism]

I'm no expert on this matter but vibration in L4 engines has two contributing factors: primary imbalance factors such as physical crank/rod/piston imbalance while spinning (denoted primary balance), and inertia of the rotating mass of all the parts (denoted secondary imbalance). Primary imbalance can be addressed by physically balancing all the rotating parts but to combat secondary imbalance factors a balance shaft is needed. You can spend all kinds of money trying to perfect the primary balance, but there is only so much value that can be added this way. The Japanese typically do a good job in this regard so splitting hairs balancing a crank is pretty much non value added.

 

[trippivot]

I am thinking of a one-time-only opening up of my '85 GS1150 and having the crank balanced and completely welded. I already know that the wear and tear factors are improved, but what I was really wondering was does it make the motor smoother or just move the resonances to another rev area?

balance your stock piston assemblies to the same one-tenth of a gram with a digital scale and put a set of APE tool steel wrist pins into your engine - you'll feel less vibration.

your crank is fine - you can spray 80HP of nitrous to a stock 1150 crank. - spend some money on a set of .348 drop in cams -- that is bang for the buck.


balancing a crank? - only helps at 1 specific RPM - not the whole revving range -it takes complex fixtures to dynamically balance a specific reciprocating weight to a specific RPM...

so you have to have to ask your self,, self? what are we really going to do with this engine?

I have great success with Mr. Pearson crankshafts.

 

[Guest]

Inline four, non cross plane cranks are self cancelling. On the plain bearing cranks, we don't use bob weights.

 

[madmikeracing]

Just to add our reciprocating parts were Balanced very close. (Rods piston assblies) Just the crank was hacksawed and smoothed , Not much vibration and this was a engine over 1000 cc started as a 750 and we revved the hell out of it also, It also ran on Alcohol, Mike

 

[londonboards]

Crankshaft builder here in the UK replaced a main bearing, welded it all up and did a balancing for me. Still not back in the motor so I can't tell you what it's like. On my rideable GS1150, heavy bar end weights stop the fingers going numb - or just go at over 5,000 rpm - that seems to work.

Here is the balancing work:

Here's a bunch more pics: Crank

And this is how he does it: