When two joined things move relative to each other, they need some sort of lubricant between the rubbing surfaces to keep them from wearing out in no time. Some parts like gears need less viscous lubricants like oil while parts like your bike’s swingarm pivots need grease.
Since it is impractical to dismantle the entire assembly to regrease it periodically, grease nipples are fitted on such parts. The grease nipple is basically a one-way valve that admits the grease into the area where it is needed, but prevents it from seeping out. This is achieved by a ball held in place by a spring on to its seat. When the grease gun is pressed onto the nipple and grease is forced upon it by pressure, the grease pushes against the ball which moves inward against the spring tension, thus allowing the lubricant to be admitted within. Once the grease gun is removed, the absence of the pressure of the grease passing through the gun causes the spring to move the ball forward, thus sealing the nipple.
The downside is that most people forget to use the grease gun on the nipple periodically and as a result, the ball sticks in its seat. Here’s how you can service the grease nipple.
Clean cotton rags, a shallow trough, some kerosene, a pointy nail, a piece of stiff wire, a spanner of the appropriate size to open the nipple.
- Using the appropriate well- fitting spanner, open the nipple off the assembly.
- Submerge it in the kerosene for a couple of hours. Then, using the stiff wire, clean out the old grease from the hole that fits in to the assembly.
- Dip the nipple into the kerosene, and using the nail, gently push on the ball. Be careful to not let the nail slip and stab you in the fingers. Keep doing this till it is clean and free.
- Remove the nipple from the kerosene and clean it dry with the cotton rags.
- Refit the nipple and using the appropriate grease gun, regrease it. ν
Preethi Reganti writes:
I have inherited my grandad’s old Royal Enfield Bullet and I intend to keep it in fine fettle as an ode to him. He really loved the bike and I am yet to figure out what it takes to keep it going. I’ve managed to learn how to start it, but my dad says that there’s a strange noise emanating from the engine. It’s a sort of a loud grating sound coming from the left side of the engine. What could it be due to? I’m petrified to ride it as I don’t want to break anything. Help!
Thanks for writing in. And I am sure that your grandfather must be proud to see his granddaughter jumping into the old bike scene with both legs! The grating sound from the left in all probability would be a loose clutch chain. The clutch chain is tensioned by a pad that is adjustable. However, the adjustment bolt is known to loosen and therefore the tension on the chain reduces, and it begins to run on to the casing. Also, it could just be down to a worn-out chain that is well past its usable range. Sometimes, the rotor of the alternator can open up and rub all over, causing the sound you mention. In any case, do open up the clutch cover and inspect it. It’s an easy fix and a great way to get acquainted with your beautiful family heirloom.
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[The article originally appeared in the August 2020 issue of Motoring World]