G9 engine, counter balance shaft

1fatcat

Hello, I am looking for some information on the G9 engine. This engine uses a counter weight balance shaft that engages the crankshaft via a set of gears. The gears are the same size/tooth count so the shaft spins at a 1:1 ratio with the crankshaft but in the opposite rotational direction. It is used to help smooth out engine vibrations by swinging its counterweight in the exact opposite direction of the crankshaft counterweights. This counterweight is much smaller than the crankshaft weights, but still a considerable amount of weight given the RPM it is spinning at.

This shaft serves no other purpose than to smooth out the engine vibrations. It is not associated with the camshaft, valve train, or any other moving parts in the engine.

I am working on a neighbors G9 that was most likely run low on oil (had lots of big leaks) and the balance shaft bearing bore got chewed up on the cylinder half of the engine case. The case half alone is $550 and there are still many other parts needed (gaskets, piston and seals). The total price in parts to do the repairs correctly is more than he wants to put into the cart. We are still hoping to come across a good used engine but I wanted to explore a last resort option and was hoping to get some feed back from all of you!

I was wondering about just leaving the balance shaft out of the engine? I know it will run fine without it, but I don't know how bad it will shake/vibrate? Will it vibrate so bad that it shakes the cart apart? Will it through off the balance of the engine so much that it wears the other bearings prematurely? Will it shake the carburetor so bad that the fuel slosh prohibits the carb from working properly? Has anyone ever tried this?

Thank you, Scott

BGW

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cart de golf

Why don’t you just find a good used engine & replace this one

It don’t seem to be worth fixing up especially if you start removing parts from it

Make him spend money then find out the motor won’t run properly & vibrates

Lots of people are installing big block & selling there engine cheap

1fatcat

Any racers out there that may have tried it to reduce rotating mass?

groundpounder

this is not a good idea. it will throw that motor way of balance.

Flintrock

Let's face it, those Yamaha engineers weren't stupid. They designed a heck of a machine, and if they could have left that da$$ thing out they would have!

BigBlockMan

Actually I have seen several with it removed, Works alot better than I ever thought it would. If no one told you it was removed you could not tell. One of my "thrifty" customers has been running his this way for 3 years, Still going fine. Look at it this way if the block is already junk and he can get 3-4 years out of it ????

Flintrock

That's good to know, I would never have guessed!

spriddle

If you decide to get another engine, check this out. I doubt you'll find a better deal.

http://www.jandmgolfcarts.com/engines.htm

groundpounder

thanks for the good info on this tom

1fatcat

Thanks bigblockman. I thought it should work fine, but didn't really want to be the first to try it