Kohler Ch25-S Engine Crankshaft Delimma?

[arp35]

Hi Everyone,
I have a Kohler CH25 Horizontal Shaft engine. The shaft is 1 7/16" with a 1/4" keyway. The previous owner welded a 1" step down shaft onto the original shaft. The problem is now the shaft is about 10" long so I would have to mount the engine farther to the left in order to line up the clutches. Not to mention the stress to the engine from having the extra length/weight of the step down. My questions are:
1. Should I leave it like it is and try to make it work?
2. Remove the welded on stepdown shaft and the have the original shaft turned down to an inch?
3. Buy a new crankshaft with a 1 inch shaft (part number 24-014-22-S) for about $185.00 and have it swapped out? The crankshafts have common deminsions so I think it is possible.
Thanks for your help.
Al

[duckhunt81]

All of your options has an up or down side. Do you have a clutch already for the 1" bore? If so, I personaly would buy the 1" crankshaft, this would give you an chance to freshen the motor (since it looks to be used) and replace wareable parts. If you don't have a clutch, see what you options are on a 1-7/16" bore clutch so you can cut that step down off.
On another note, are you using this on the Hustler? If so take the air cleaner assembly off, set the motor on the frame (in the tub) and check you clearances with the back seat. I think it's going to be a close fit with the starter side valve cover, which make me think that air cleaner won't make it in there, just as a sugestion.

[arp35]

I don't mind losing the back seat. I can't ever imaging using it anyway. I will most likely convert the back area into a cargo carrier. I don't have a clutch for the motor. But I was under the impression that they all required either a 1" or 1 1/8" shaft. Where would I find a suitable match for the T-20 that had a 1 7/16" bore? I am also afraid if I cut the step down off then I won't have enough shaft left to mount the clutch. Your thoughts?

[Mike]

I'm not much help but just wanted to throw another option out there. Finding a used crankshaft by either buying a junk motor or checking with your local small engine shop.

[arp35]

I guess I will wait and see. I received a new muffler for the motor today and am waiting for the air filters to arrive then I can start working on it to make sure it is running Ok before I decide what to do. If possible, I may just try to fabricate a wider motor mount and use it like it is. Worse case I may just sell it and buy a new one. If I go that route any one have a favorite four stroke that would mount up using the standard mounting plate? Which motor is the best? Another Kohler 25 or the Vanguard 18?

[Dennis Saskowski]

If you fixed your problem disregaurd this post. I have a crank from a blown 25 motor,200 hrs. from a 1999 . The crank was checked for true, magnafluxed & the journals polished and mic'ed.at min. diameter. Might not get back home 'till x-mas if you can wait.

[arp35]

Thanks Dennis, I would definitely be interested in the crankshaft. Does it have a 1 inch shaft? I am currently waiting on my bands to come back from the transmission shop. Once I get them (hopefully today), I am going to rebuild the T-20, get it back in the machine, connect up the chains/axles/sprockets, then put the wheels on. If everything checks out then my next step is to start on the engine. I bought a new cylinder head and rebuild kit so I will have a lot the internals taken out (at least on one side). So it would be a great time to go all the way and swap out the crankshaft. But before I do anything I am going to trial fit the engine in the tub to see about clearances, etc. I have two tops and will probably modify one of them to accommodate the engine and converting the backend into a cargo area versus a back seat. More info then you probably wanted to read but bottom-line is I would definitely be intersted in the crankshaft as long as it is either a 1 or 1 1/8" diameter shaft. Let me know.
Al

[arp35]

I purchased a crankshaft with a 1" diameter shaft off of Ebay. I probably should have asked this question before the purchase but figured I should buy it while it was available. Any experts on time and trouble to swap out the crankshafts? I have a copy of the tech manual which shows how to completely disassemble the engine but I am wondering if there is a shortcut? I have a rebuild kit for the #1 cylinder with a new cylinder head and gaskets. So I will have at least that much to disassemble. Also, what else should I purchase to do this right? Are there more gaskets needed? How about crankshaft bearings? Should I bother replacing them or just reuse the original ones? Any help/suggestions are appreciated before I start tearing it apart.

[arp35]

New 1" crankshaft installed!

Well I wanted to update my progress on the Kohler CH25. I completely disassembled it and am painfully rebuilding it. This is my first engine rebuild so I am taking my time and closely following the Kohler Service Manual. So far I have replaced the funky crankshaft with a regular 1" crankshaft, replaced the #2 cylinder head with all new valves, push rods, springs, etc. I also replaced the piston rings on both sides. Hopefully the new #1 cylinder head will arrive tomorrow and I can finish installing its valve springs, rockers, stems, push rods, etc. I originally was only going to replace the one cylinder head due to the exhaust stem bolt breaking off but for some dumb reason I ordered the wrong one. So I decided to go ahead and use it and just order the one I really needed. I also lapped the valve heads All new gaskets all over the place and of course new cylinder head bolts on both sides. I am hoping to get it all back together this week and have its inaugural start/running this weekend. It has been an interesting experience but really simpler than I thought. But I am not surprised I could not find a small engine shop to do the work because it is both time and labor intensive. I'm sure once you did a few, those of you, could rebuild one with your eyes closed but for me it is one page at a time. I also ordered a new CVTech Clutch and belt from RR's. I am starting to see the light at the end of the tunnel but I could not have done it without all the great help here on 6x6 World. Thanks and more to follow...

[Mike]

It is very cool that you took on the rebuild yourself. Thanks for sharing the pictures and your experience rebuilding it. It will all be worth it soon. Keep us updated.

[arp35]

It is very cool that you took on the rebuild yourself. Thanks for sharing the pictures and your experience rebuilding it. It will all be worth it soon. Keep us updated.

Finally completed the engine rebuild! It purrs like a kitten I ran it for about 10 minutes and it did awesome (pretty proud of myself)! I am going to spend some time tomorrow getting it mounted in the Hustler. I believe I can use the two holes pre-drilled in the mounting plate on the far left side but will have to drill the opposite 2 holes since the ones already on the plate are to far apart. I have read where the fixed plates on the 2 clutches need to be about 5/16th of an inch apart and parallel. I am guessing the fixed plate on the drive clutch needs to be the one that is 5/16th of an inch inside or outside of the driven clutch? Also, are there any tips on mounting the engine onto the mounting plate correctly?
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