K321 rebuild kit.

[BurtB 106]

I tried searching but didn't find a recommended vendor for engine rebuild kits. Also looked through the vendors and didn't see rebuild kits. Sorry if I missed something obvious.

 

Looking at this kit on Little Red Barn.

 

Is there a better source or preferred vendor for rebuild kits?

[JoeM 9,040]

A while back I seen a tuber using the LRB stuff and bragged it up.

A lot of folks liked I save tractors but they are gone.

 

[WHX?? 53,079]

Bought lots of ring sets from LRB and happy. Yes prolly Chinesium but OK for the hobbyist and something that is not going to the moon. 

There are several other sellers on fleabay that I was happy with. Their names or handles escape me. One was something like batforkids. 

[ebinmaine 74,934]

3 hours ago, WHX?? said:

Bought lots of ring sets from LRB and happy. Yes prolly Chinesium but OK for the hobbyist and something that is not going to the moon. 

There are several other sellers on fleabay that I was happy with. Their names or handles escape me. One was something like batforkids. 

 

 

@Achto  ?

[ebinmaine 74,934]

I'm curious about decent engine kits as well. 

We have several K series to be done in the coming years. 

 

 

[Achto 30,026]

I like the kits sold by The Man's One Stop Shop. Have also had good luck with Lil Red Barn Power Equipment Supply. Both are suppliers on Ebay

Edited September 23 by Achto

[MainelyWheelhorse 2,143]

6 minutes ago, ebinmaine said:

I'm curious about decent engine kits as well. 

We have several K series to be done in the coming years. 

 

 

After looking at the K181 out of the C-85 I have I’m tempted to find a good kit as well and put it back together as a backup.

[RED-Z06 2,685]

Ive used LRB a few times and my experience is mixed.  Rebuilt a few homelite saws and their pistons never fit right.  I rebuilt a K181 and the piston, rings, seals, etc...were great, but the STD rod was too tight on the crank, is measured basically 0.000 oil clearance.

[BurtB 106]

Thanks y'all! I going to go inspect the crank bearings, haven't cleaned them and felt/looked closely but they felt good when I took them out. I'll make an order to LRB this evening depending on their shipping costs vs ebay.

 

6 minutes ago, RED-Z06 said:

I rebuilt a K181 and the piston, rings, seals, etc...were great, but the STD rod was too tight on the crank, is measured basically 0.000 oil clearance.

 

I was in highschool (at the end of the last century) when I rebuilt a B&S, otherwise I'm long on theory and short on experience. You think I need plastigage for this or will my mics tell me what I need to know?

[WHX?? 53,079]

37 minutes ago, Achto said:

I like the kits sold by The Man's One Stop Shop. Have also had good luck with Lil Red Barn Power Equipment Supply. Both are suppliers on Ebay

Yep ther was a man's one pit stop or somethin like that. 

 

29 minutes ago, MainelyWheelhorse said:

find a good kit as well and put it back together as a backup.

Yep if I get get the kits resonable and don't need alot of machine work ... read $$... I love to have shelf spares. Can always sell it for what you have into it. 

 

25 minutes ago, RED-Z06 said:

 their pistons never fit right.  I rebuilt a K181 and the piston, rings, seals, etc...were great, but the STD rod was too tight on the crank

I believe anytime a piston or rod is replaced the bore/crank must be worked to fit the parts. The machine shops job. 

 Unless one gets blind outhouse lucky.

Too much variations in the different manufacturers. 

[RED-Z06 2,685]

6 hours ago, WHX?? said:

Yep ther was a man's one pit stop or somethin like that. 

 

Yep if I get get the kits resonable and don't need alot of machine work ... read $$... I love to have shelf spares. Can always sell it for what you have into it. 

 

I believe anytime a piston or rod is replaced the bore/crank must be worked to fit the parts. The machine shops job. 

 Unless one gets blind outhouse lucky.

Too much variations in the different manufacturers. 

Its not 'suppposed' to be that way, Kohler parts were always dead nuts in spec out the box.  Aftermarket stuff you get tolerance stacking.  

 

If a new STD crank pin should be 1.500 with a tolerance of 1.501 to 1.499 for example, and a Rod big and diameter of 1.508 to 1.505, Kohler would send out a new STD rod at 1.505, knowing that the crank is, at best new..at worst, small end of spec and thats still in tolerance.

 

The chinese parts makers, they would send it out at anywhere from 1.500 to 1.515, it could fit perfectly, too loose, or too tight.  

 

Kohler, Briggs, Kawasaki...rebuilds were easy, if one part is in STD spec, order the wear part and move on...you could trust new parts, they had to stand behind them.

 

When i contacted LRB about my $65 piston that was 1mm too big for my cylinder they were like...damn that sucks, oh well, we will look into it.

[953 nut 62,566]

On 9/23/2025 at 12:57 PM, BurtB said:

You think I need plastigage for this

Plastigage is a must.        Top, bottom and sides of the crank journal should all be checked for clearance when a new rod is being installed.

I would rather buy another rod than install one that wasn't within tolerance for lubrication and have it fail.

Edited September 25 by 953 nut

[BurtB 106]

3 hours ago, 953 nut said:

Plastigage is a must.

 

I'll get some coming.

 

I think the rebuild kit just showed up. Ended up ordering bearings as well, they didn't feel perfect and one of them had an intermittent grab. Need to get the piston and such to the shop.