Clutch Drag Solutions

I have over time found some ways to reduce some or nearly all clutch drag.  There are two approaches to this problem.

1.  Change the primary oil to something with less drag.

Over time I have used a variety of oils. I have tried Golden Spectro Golden Gear Lube and STP.  Both are guaranteed to cause slippage.  Lots of it. The clutch doesn’t work. You get the idea. I have used BG EPC (extreme pressure concentrate). Same result. I know of one motorcycle oil that has this in its chemical package.  Bel Ray. Montesa recommends a 10W30 engine oil. Since most Montesas have a primary gear, I prefer to use a motorcycle 4-stroke cycle oil that has an additive package to provide lubrication for the transmission.

I have discovered a very good oil. Its smallest quantity is a 5 gal. bucket. It’s made by Schaffer’s Oil Company.  They usually sell to farms for combines and to trucking companies. It is #275s DI-LUX.  Fifty gallons are used in a wheat harvester. If you can find someone that uses it commercially and has a few gallons left over, you might get lucky. You can check the composition of the oil on line and purchase a similar lubricant at an auto parts store.

If your engine uses the clutch pack with the numbers 0263.023, change them to the clutch pack # 5363.023.

2.  Springs.

The clutch uses 6 springs. No two springs are exactly the same. You can balance the pressure by pairing.  You will need an accurate scale and a drill press that has a repeatable stop. Place the scale on the drill table and compress each spring to the stop. Record each reading. Pair the most equal springs for installation opposite each other during the reassembly.

I have done this on my 250 Impala. This motorcycle can be sitting for years, and I can pull in the clutch lever and select first gear with no resistance to rolling motion until I release the clutch lever. COOL!  You may not have as much success but it can’t hurt to try.

Additional Comments:

There are other types of clutches. I haven’t covered the Cota 25 or any of the 49 cc engines. These are an entirely different arrangement. Only one clutch plate is involved and it has a friction material on it.

The other clutch I have become familiar with is the one designed for the Cota 242, 330, 335, 304, etc. These have a clutch pack that is part of the clutch basket. There is a large retaining clip that holds this together. It will take a press of some sort to compress the pack to access the individual discs. This clutch pack is composed of metal and friction material discs. There seems to be only one flaw. The outer pressure plate tented to crack and will need replacement. There is also a good possibility that warpage may occur to the plates.  Replacement of the discs and/or pressure plates is necessary to return this clutch to working order. 

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