Serpentine Pulley Set

Best Quality Custom Pulley Set while they last!

Build your own reliable and flexible Generator set based on the two bearing generators that has been in production for more than 100 years for a reason. It’s the product Mad Max would pick every time, because you can trouble shoot the problem, change out the prime mover and so much more with ease.

Who sells this type of head? Everyone from Marathon, Winco, Harbor Freight, and more.

Our Hemisphere uses 60hz as our standard.  RPM and frequency are tied together, this means we MUST turn our two pole generators at 3600 RPMs in order to provide 60hz with the typical 2 pole generator we find for sale from many suppliers.  You may have read my article about rescuing a generator section from a scraped gasoline generator and building a new end to carry the second bearing, It’s fairly easy for a DIYer with basic machine skills to do.

There are a number of old Industrial Kohlers that were rated to turn 3000 RPM, and now we can find the small single cylinder diesels made by a number of companies including Kohler! some are not cheap, others are thrifty with mixed reviews, the Yanmar clone is popular with some, and I have a few customers with 300 plushours on them, that’s more than a lot of people will put on them in a life time for standby generator operations, like backup to storms for the critical loads in your house. Saving a freezer full of beef one time, along with the contents of your fridge can make you feel like it was all worth your effort to build a Generator.

Some of these engines are power rated at 3600 RPMs, many of us like to cut them back to 3000, for the sake of longevity and noise reduction. The 5.0 inch serpentine pulley on the engine, and the 4.2 inch pulley on the two pole generator can put you in the sweet spot, and if you must have full rated power, 4.2″:4.2″ will allow your engine to run at full speed, and will allow you to produce higher KW output if your generator is capable of producing same.

4.2 and 4.1 pulleys are $59 plus shipping

5.0″ are $79 Plus shipping

The combo  5.0″ and Either 4.1 or 4.2 inch are $140 >Delivery Included< in the USA

Utterpower Pulleys use the very easy to find QD SK bushings, and as I say elsewhere, once you use a taper lock bushing, you’ll never mess with other solutions when reliable operation is the goal.

I do stock 42mm and 38mm bushings for the ST generator heads, I will beat any price you find on these, and other sizes are found at Grainger and many other suppliers QD-SK is what you ask for..






14 Responses to Serpentine Pulley Set

  1. Bob Mason says:

    4.1 pulleys are $59 plus shipping
    I am trying to put together a machine for a home made application.
    The 4.1 pulley: the bore is 1 inch?
    If this is correct I would like to order a pully, with more in the future if it works.

    • George B. says:


      I don’t use bored pulleys unless forced to do so, all pulleys I deal in are set up for bushed pulleys.. QD SKs when ever possible, then you order the size bore you need in the bushing.. sounds liek a pain, but once you use bushed pulleys, you just don’t like the others..

  2. Bob Mason says:

    I am trying to set up a 4 inch OD serpentine drive wheel. The bore of the motor drive is 1 inch.
    The taper lock bushing sounds like the perfect solution.
    Where can I buy the 4 inch OD serpentine drive wheel and taper lock bushing?

  3. George Fahrenholz says:

    Hi George – I would like to run my Yanmar L70V6-L at 3000 rpm and drive your PMG that I purchased awhile ago from you. I think I need the 5 inch serpentine pulley on the Yanmar, as the PMG looks to have the 4.2 inch already on it… how do I buy the 5 inch pulley from you? And is this the right combo for driving the PMG?



  4. Daniel Moore says:

    Hello, I bought an AURORA 6500 diesel generator in 2009. When I had the manual transfer switch installed in the house, the electrician told me to have my generator looked at. Well, I have had one disappointing experience after another !
    I have read some of your articles and I feel my situation might finally have a tolerable end.
    In order to acheive the 60 htz, this generator just about shakes apart. The engine also sounds bad as it sounds as if missing at 3600 rpm. It wants to run seemingly well below 3400 rpm’s. I would appreciate any advice. Thank you

  5. Roy Taylor says:

    I’d be interested in a pulley setup to link a 195 changfa to my 7.5 kW st head.
    Do you have this ?

    • Roy Taylor says:

      I sure would like to buy a pulley set to lnk a 195 changfa clone to a 7.5 kW st and 10kW st gen head to a changfa. I want to be able to use one or the other as a spare. Please send a quote at your earliest convenience

  6. JUSTON says:

    I just bought a Satyajeet gm 90 6 hp. Has 2 inch shaft. And have your 7.5 st head. Need pulley a bushing for both. Can I order this through you?

  7. Lyman Schwartz says:

    Hello George, Some years ago I purchase from you a 8 1/2″, 8 groove pulley for on my 1800 RPM Generator ST-5…. The Engine is a Power Line 6-1…… It really works great and I have put together a second Power Plant same as the first. Is there any way that I could get another pulley same as the first. If you are out, is there any way that you will be having more made. I would be willing to pay extra if you could get me one. Thanks, Lyman Schwartz 1045 Barlow-Two Taverns Rd. Gettysburg, PA 17325

    • George B. says:

      I’d like the world to know what an excellent donor part a Ford 3/4 ton Truck front hub is. You basically cut off the rotor, bore the center for the QD SK Bushing,and then machine the serpentine pattern on the outside. Randy Allmand doesn’t like to do the job, and he says people need to be careful when cutting off the brake rotor.

      There’s just noT enough demand for me to make pulleys, but this is a great DIY. Dont screw up on the spacing of the grooves, that’s a mistake the Novice might make…

  8. George B. says:

    I know this is a very old post, but now that I am back in, all pulleys are eight groove, the QD SK bushing steps down through the fractional inch shafts.

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