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That RL250 Clutch!

A persistent complaint of RL250 owners is the effort required to pull the clutch. It is often just too difficult for riders of smaller stature to use and it also makes the process of slipping the clutch in the slower sections almost impossible.

My experience with the RL250 clutch mechanism is that the high forces required to operate the clutch is tied in with the amount of use on the bike. In other words, the force required to operate the clutch will increase as the bike is used and advances in age.

This was most evident to me after I had purchased a 1975 RL250 from a fellow in Montana. Even though we had discussed the bike and I had seen pictures, I was still amazed at the condition of the bike. It looked almost new. The relevance to this discussion was the, dare I say, silky smooth operation of the clutch.

I had been investigating the clutch for possible improvements and felt lucky to have such a remarkable example at hand. The clutch on my bike was never too bad but it certainly didn't feel as good as the Montana bike's clutch. In order to troubleshoot the problem, I swapped the clutch cable and magneto cover but did not note any big change. This was an important step. The clutch release screw assembly is mounted within the magneto cover and that, along with the cable and the way the cable is routed through the frame, could introduce a large amount of drag. Since swapping those pieces didn't provide much change, the only area left to consider was inside the engine.

The screw assembly contacts the end of the clutch push rod. The clutch push rod, actually two equal length rods, passes through a hole bored through the transmission countershaft to the clutch pack pressure plate located on the right side of the engine. When the clutch lever is pulled, the screw assembly rotates pushing the rods and pressure plate to the right to release pressure on the clutch plates.

The weak link in the mechanism is the two rod setup. The rods are of a relatively soft steel with tempered ends. The rods bend under compression as the lever is pulled against the tension of the clutch springs. This causes the rods to wedge against the wall of the bore through the countershaft. In addition, the ends of the rods that touch one another will wear and displace applying additional pressure against the bore wall.

The fix for the problem is the Matrix EZE-PULL Clutch Modification Kit. The kit includes a new hardened tool steel one-piece rod that spans the distance between the screw assembly and the clutch pressure plate push piece. Included in the kit is a new push rod oil seal, a magneto cover gasket, a clutch cover gasket, and new custom wound clutch springs. The springs are utilized to further reduce the effort required to pull the clutch lever and is essential if people of 'smaller stature' ride the bike.

The kit includes three new custom wound springs. I elected to go this route rather than an all new set of six springs. Six springs would cost twice as much and the purchase price would be much higher. Secondly, the combination of three new springs installed alternately with three existing springs will provide the desired effect with no tipping of the pressure plate.

The result is a clutch that operates smoothly and predictably with a 20% reduction in the effort to pull the clutch lever. With this kit and proper attention to the other areas of concern listed below, the RL250 clutch will operate as well as any bike of the era.

A complete set of installation instructions with a required tool list is included. The kit can be installed by a reasonably handy owner with a small selection of metric hand tools in 2-3 hours. You will need to locally purchase new transmission oil. Before doing so you might check out the discussion on Transmission Servicing.

Other areas to inspect and correct concerning the operation of the clutch are;

bulletLever pivot lubrication
bulletClutch cable wear/fraying/ kinking
bulletIncorrect cable routing that either stretches or kinks the cable when the forks are turned to their limits
bulletInsufficient lubrication in the screw assembly

Correcting problems in these areas will improve the operation of the clutch. Periodic maintenance is also important.

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Copyright 2014 Matrix Motor Sport
Last modified: 05/26/14