12 hp balance gears
 

I'm rebuilding a k301 for my fathers 125 and I am debating re-installing the balance gears? The engine is very low hours and the bearings and end play was good. The only reason I'm rebuilding it is because of rust in the cylinder.


Meant balance gears in title.

Some people do re install them, but most do not. They don't make that much difference in how smooth the engine runs, but if they go bad, they have the bad habit of knocking unwanted holes in the sides of the block. For that reason, very few people re install them when rebuilding a motor.

I dont reinstall them, and I take them out of all the engs I own. One day they will go flying threw the side of the block. Then you will have positive ventlation into you block!

I remove the balance gears from my Cubs soon after bringing them home.

Throw those gears as far away from the engine as you can.

I would pull them out and keep them on the bench.



I fixed your title for you too.:beerchug:

i would keep them, they make excellent weights to hold down the pages of your manual when you are doing maintainance and you can't remember certain specs!!!!! :biggrin2::biggrin2: jeff

Thanks for all the info! I'll be leavening them out for sure then.

I'll be putting a new set back in my k301. as long as you put new parts back in it'll be fine. they say there isnt much vibration (bull) I should of not taken the advice of others. it vibrates the the hood, front light area, heat shield. drives me nuts.

Reinstalling balance gears
 

Doug-

I personally agree with what the others have said here and toss all "grenade" gears. The engine does shake a tad more at idle but after you reach mid to wot the vibrations are no different than before. Another alternative to reinstalling the gears is to have you crank balanced. I've read this will bring the shaking/vibrations back to roughly where it was with the gears installed. This will eliminate the possibility of a blown engine due to the gears needle bearings giving out.

Just my .02 worth.

I like crusing the tractor shows with my 125. but not at 2800 to 3200 rpm.

I will check into having the crank balanced. that does make more sence then taking a chance on getting a hole in the block.

I have about 18 Kseries Kohlers and I've never seen the balance gears cause a problem. I do have one that runs very rough and I suspect someone has removed the gears under discussion.

You could always get a Crankshaft Balance Plate Kit from Kirk Engines.

12 hp Balance Gears
 

Has anyone tried the balance plates from Kirk Engineering?

I have not, but I'm thinking about if/when I get around to rebuilding the 10hp I have sitting around. Only $20, so I skip the good beer for a couple weeks.

I just rebuilt my K341,

It had no balance gears- I thought long and hard about changing the balance weight. I read a long article on varies ideal balancing for single motorcycle engine varies by the installation and cylinder orientation.

I'm not convinced lowering the vertical and doubling the horizontal secondary moments will make it feel smoother or rougher. The larger side to side seems like it would be worse.. So I choose to leave it alone.


Michael

Doug,

My K-301 runs rough too, so much that I was once concerned about the fillings in my teeth.

I have a Quietline, and while I haven't had the pan off that engine, I believe that Kohler left out the balance gears on the engines used in the Quietlines. To counteract the problem, I tightened the ISO mounts and opened the crack screw on the carburetor a little bit. It helped.

Crack screw?
 

Brian,

What is the "crack screw" on the carb? Or did you mean to say you "cracked the [Idle Fuel / Main Fuel / Idle Speed] screw [open/closed] a little" on the carb?

--Just giving you a hard time, but seriously, didn't you adjust the idle speed up to the QL specified 1,000 RPM or so?

Jeremiah

If you've found a "crack screw" I hope you haven't been "using" --the only thing you should be smoking near a Cub is gasoline and 30W oil (with perhaps a dash of Marvel Mystery Oil).

I just had a balance plate from Kirk engines installed on a K321 crank. I'll definitely post the results once it is back in my 149. John