In A Clutch Essay, Research Paper
IN A CLUTCH
In the old biker days before the modern age Yuppie bikers, who buy outrageously priced new Harleys and then pay to have tons of chrome accessories added to them. We actually built and maintained our Harley-Davidson Motorcycles ourselves. No two bikes were the same everyone added their own personal touch to their bike. Some of us were definitely better at this than others. You could tell who the good ones were because they would be working on the other guy s bike when it was broke down on the side of the road somewhere.
One common thing that many bikers would have trouble with was the clutch. Either slipping because it was not adjusted properly or more often grabbing due to dirty clutch plates. This problem was easily cured and I will explain how, but first a little more background.
This was back in the days of the chopper. In those days most bikers would take everything off the bike that it didn t need to go faster. And then throw these parts over the fence into the neighbor s yard. Some of the more thrifty bikers squirreled those parts away in their garage attics and are now selling them for a nice profit to other old timers who have decided they now want to put their old harley s back to stock.
Back then it was common to run an open belt drive and a kick-starter. This meant you would take off your inner and outer primary covers, and your electric starter, and the original chain primary drive. Plus with out the electric starter you could run a smaller battery. All this weighed about a hundred pounds. And could be replaced by an open belt drive that weighed about fifteen pounds.
The open belt drive was just two pulleys one on the engine crankshaft and the other was a pulley and a clutch hub in one and this was on the transmission main shaft. Then there was a large toothed belt that ran between the two to transfer the power from the engine to the transmission. This was more efficient, quieter, and vibrated less that the heavier chain-drive system.
There were some draw backs to this one of them was that if you got your fingers down near the belt drive while the bike was running they could get caught between the belt and the pulley! Even at an idle you would lose them instantly, gone, nothing but bloody stumps left. I actually witnessed this once. It was not a pretty sight!
OK, let s try to forget that.
Back to the clutch and another problem of running an open system. On a stock Harley the clutch was inside the primary cover and running in oil. With an open system the clutch was dry which is fine if you keep it maintained. Actually they work even better dry if you keep your clutch plates clean. But this can be the problem. Harley transmissions almost always leak oil. Plus there is a bearing in the clutch hub that has to be kept greased in an open system. So between the oil leaking from the transmission, and the grease from the clutch hub bearing, mixing with the all the road grit, you get a gritty gummy residue on the clutch plates. Then one day while you are setting at a traffic light waiting for it to change. The clutch decides to stick and you shoot out into traffic, usually between something like a log truck with no brakes and a Redneck that hates bikers in a pickup truck.
Well if you live through that ordeal you definitely want to fix that clutch and now! The good news is it s actually pretty easy, which should make you wonder why you let it get that bad in the first place.
The whole process takes less that an hour and only requires a few basic tools. A 9/16 wrench, a regular screwdriver, and a large flat washer with a small hole, this item can be hard to find, but every hard core old school biker has one. And also some type of solvent, brake cleaner, carb cleaner, or you can even use gasoline, or kerosene, whatever you got kicking around the garage.
Now you re ready to get to work. Since you have no cover or guards on anything (And possibly no fingers) the clutch is very easy to get at. The first thing you do is loosen the clutch adjuster lock nut from the clutch adjuster screw.(See Diagram 2) Using the 9/16 s wrench and the screwdriver. Remove the lock nut. Then slip the large flat washer on the screw and put the lock nut back on and snug it down. The large flat washer holds down the clutch spring retaining ring, So that now you can remove the clutch stud nuts from the clutch studs again with the 9/16 s wrench and then remove the pressure plate, springs, and retaining ring all as one unit. After this has been removed the clutch plates will slide right out. There should be five friction plates and four steel plates. (See Diagram 1)
Now that you have the clutch plates out all that you have to do is clean them and put it back together
The steel ones are easy you just spray them with solvent or dip them in gasoline or kerosene and then dry them with a clean rag. The friction plates are a little more work. First put them in a pan and spray them with solvent or soak them in gasoline or kerosene. This will loosen up the oil and grease that has accumulated on them. Then a little scrubbing with a cleaning brush helps. Next rinse them off and let them dry.
After they have dried you need to break any glaze that may have formed on the friction plates. The best way I have found to do this is to rub them on a smooth piece of concrete, like the garage floor. Hopefully you have a clean spot of floor to do this. Rub them in a circular motion, you are using the concrete like sandpaper to scuff up the surface of the friction plates and break the glaze. Do both sides of all friction plates. Then wipe them down with a clean rag to remove any dirt or grit.
Next you just put it back together, remember to put a friction plate in first then a steel then alternate, friction, steel, friction, steel, until all the plates are back in. The last plate should be a friction plate. Then you slide the pressure plate assembly with the springs and retaining ring back on the clutch studs. Put the clutch stud nuts on and tighten them down evenly. Next you can remove the clutch adjuster lock nut again and remove the large flat washer. This time put the adjuster nut back on without the flat washer.
Now before you tighten the adjuster nut you need to adjust the clutch. Turn the clutch adjuster screw (See Diagram 2) out until it is loose, no resistance, then turn it back in until you feel it engage the clutch push rod, stop there, and then turn it back + turn. Now hold it there with the screwdriver and tighten down the clutch adjuster lock nut with the 9/16 s wrench.
Diagram 2 6
That s it the clutch is back together and adjusted. And you can be proud to say you did it yourself.
Time to light the fire and smoke the tire!
Happy HotRodding ..Harley style!