Major overhaul of K301

[Mickwhitt 4,134]

Gents, 

I'm considering a full overhaul of the K 301 on Fred.

 

Its 40 years old and still has a standard piston fitted.

 

Definitely using oil and to my ear a tiny bit of big end noise. 

 

We have an auto reboring shop nearby who also say they will do single cylinder motor bike engines etc.

If I go down this route I will need new piston, rings, shell bearings etc.

What should I be asking the machine shop to do to this engine? Obviously rebore to new piston size, regrind crank, skim cylinder face so head gasket seals better. 

I've seen a guy on ebay selling engine rebuild kits, he is in wauseon Ohio. Anyone heard of him?

Hoping to find out if this machine shop will take on the work then I can bite the bullet and strip Fred down. 

Mick 

[squonk 38,846]

Have the machine shop inspect the bore and crank BEFORE ordering anything. They will tell you what size piston you will need. Also they will be able to tell if crank can be reground. (Only .010 undersize rods available) Also replace the rod if they can't inspect it for cracks. Once you get the parts. Bring the piston to the shop so they can finish hone the cyl. for the proper clearance. Have the shop check the valve guides and grind the seats. Get new valves too.

[tunahead72 2,334]

I'll be watching, Mick.  Refresh my memory, Fred is a C-125?

 

[ebinmaine 62,975]

3 hours ago, tunahead72 said:

I'll be watching, Mick

Yepp. Me too.  

[Mickwhitt 4,134]

Yes he is a C-125 built in 1979.

So the engine is pretty original and probably deserves a good overhaul. 

I measured to bore for out of round when I initially stripped it but didn't think it was too bad using my basic measuring tools.

Im waiting to hear back from the ebay seller regarding the parts kit he supplies.

 

https://www.ebay.co.uk/itm/Kohler-K301-12HP-ENGINE-REBUILD-KIT-w-FREE-TUNE-UP-piston-020-and-rod-020-/142098712119?_trksid=p2349624.m46890.l49292

[squonk 38,846]

By basic measuring tools, what do you mean?

[Mickwhitt 4,134]

I used a telescopic bore gauge to measure the cylinder for out of round. It didn't seem too bad to me but hey, what do I know? Last time I messed with an engine to this degree I was still at auto college as an apprentice. 

I rebuilt the engine as it was mainly to see if I could get it to run and was not wasting my time.

Now it makes sense to do it right.

If I can get the machining done.

More to follow when I speak with the machine shop this week.

 

 

[Howie 882]

I think Kohler only makes a .010 under rod, but a.020 aftermarket is out there.

[Mickwhitt 4,134]

Well gents.

The machine shop I spoke to are very experienced in boring, honing, grinding etc.

I worked as a mechanic for our local council when I was a lad and we used to send all our engines there for regrind etc. And its still going strong.

He is happy to take on the job and has quoted me a ball park figure of 130 USD to bore and hone the cylinder and grind the crank journal.

SO THE BIG QUESTION...

Do I bite the bullet and take Fred off the road for a while and get the engine overhauled.

Im pretty sure it is ready for some work and will certainly not hurt anything.

The service kit of parts is another 100 USD or so depending on shipping and tax.  The guy sounds very knowledgeable and has explained how to go about ordering after the engine has been measured.

So nowhere near the expense of trying to find a new engine. 

Give me a reason not to go for it! Or of course just push me into a decision. 

Regards Mick 

 

 

[ebinmaine 62,975]

Those are GREAT prices for my area. 

 

Hey if it needs fixing. ..  And it's the off season for mowing?

 

Do it now. 

 

Says the looloo in Maine while he spends Mick money. 

[richmondred01 2,202]

19 hours ago, Mickwhitt said:

Well gents.

The machine shop I spoke to are very experienced in boring, honing, grinding etc.

I worked as a mechanic for our local council when I was a lad and we used to send all our engines there for regrind etc. And its still going strong.

He is happy to take on the job and has quoted me a ball park figure of 130 USD to bore and hone the cylinder and grind the crank journal.

SO THE BIG QUESTION...

Do I bite the bullet and take Fred off the road for a while and get the engine overhauled.

Im pretty sure it is ready for some work and will certainly not hurt anything.

The service kit of parts is another 100 USD or so depending on shipping and tax.  The guy sounds very knowledgeable and has explained how to go about ordering after the engine has been measured.

So nowhere near the expense of trying to find a new engine. 

Give me a reason not to go for it! Or of course just push me into a decision. 

Regards Mick 

 

 

Get it done. That’s a good price on machine work.

also take a good look at the valve guides easy to replace now while it’s torn down.

 

[Mickwhitt 4,134]

Ok, you've convinced me. I want to be sure this little red Fred keeps on going so its only right that I tear him down and give him a good going over.

I don't suppose you want any photos taking as I do it huh?

 

[richmondred01 2,202]

I’ve dealt with Kevin before. His parts are rotary and steins. 
You will be fine using him. He also sell guides.

Theres a trick to removing and installing guides that’s down and dirty and works well.

let me know when you are at the point.

Also don’t loose the .005 spacer, it may also be .003 or .010 that is located on the PTO side of the cam. 
Additionally, label the valve tappets as exhaust and intake. They are different.  
all the best. 

[Mickwhitt 4,134]

Right ho.  The job has begun, I got my tiny shop set up to remove the engine from Fred and will park the chassis out of the way while I work on the engine.

Im hoping for a pretty quick turn round with the only things out of my hands being the machining and the parts delivery.

With any luck Fred will run for another 40 years by which time I won't be so bothered lol.

The oil was very dirty and black when I dropped it, so we need to do this.

Mick 

[ebinmaine 62,975]

I'll be looking forward to seeing your progress on this one.

Hopefully you have your camera button pushing finger primed up and ready to go.

 

[Mickwhitt 4,134]

Absolutely Eric.

The engine is now sitting on my work bench awaiting tear down.

[tunahead72 2,334]

Nice sign...  You'll fill us in on its special meaning in your world? 

 

[Mickwhitt 4,134]

Oops!  Sorry.

 

Thats a joke licence plate from Ireland my lovely wife brought me back as a gift.

 

Not sure what vehicle she had in mind for me to display it on.

 

Mick 

[WHX?? 46,703]

On 1/12/2021 at 8:36 AM, richmondred01 said:

’ve dealt with Kevin before. His parts are rotary and steins. 
You will be fine using him.

I'll second that. Bought kits from him and always ok. Yes not original Kohler but those are ridiculous priced and Rotary/Stens work fine.   Just be sure to convey to him what size pistons/rods you need. 

 

Best you do this now Mick before the block gets ventilated. Are those solid mounts I see on the shaker plate? 

[WHX?? 46,703]

On 1/12/2021 at 8:36 AM, richmondred01 said:

label the valve tappets as exhaust and intake

2nd that too, I just clean them off and mark them X & I on the face. 

[The Tuul Crib 7,332]

I just got a kit from him yesterday and looking at the connecting rod has a 25 mm written on it .I'm assuming that the measurement then to have the crank turn would be at that size rather than 10 under 

In thousands?  eh?  @WHX24

[squonk 38,846]

1 hour ago, The Tuul Crib said:

I just got a kit from him yesterday and looking at the connecting rod has a 25 mm written on it .I'm assuming that the measurement then to have the crank turn would be at that size rather than 10 under 

In thousands?  eh?  @WHX24

Are you sure it isn't 2.5MM?   2.5MM is .010"

Edited January 13, 2021 by squonk

[Mickwhitt 4,134]

0.010 in is actually 0.25 mm not 2.5mm

 

[squonk 38,846]

Opp s I moved the decimal. But I think TC'S rod is the .010 rod

[WHX?? 46,703]

Put the calipers to it to be sure. Wouldn't be the first time something got packaged wrong.