Acoustics of Royal Enfield CI models

This post will sound funny (even hilarious) to many of us but I thought to share this based on my experience with CI bullet and also based on various issues posted by bullet owners. Here are the various sounds come from bullet, what could be the possible reasons and remedy to it.

  

1. If you listen lot of Hissing sound (snake like sound) from head of engine then it generally it comes the pulse air valve mechanism (also called Euro II pipe). This is normal for CI models post 2006 If sound is very loud then check the damage in rubber air pipe that connect PAV to carburetor manifold for any damage.

Remedy : You can ask mechanic to block the PAV with small iron ball and change the pipe if damaged.

2. Low intensity Popping sound from the silencer when you close the silencer while riding (phatt  phutt … phat …phatt).  4-5 in a row with 1 – 2 second gap . 

Reason: Its sign of lean fuel mixture.

Remedy: Time to retune the carburetor settings.

3. Loud cracker sound from the silencer when you close the silencer while riding (scary enough like gunfire , misfire).    

Reason: Its sign of rich fuel mixture or carbon deposit on spark plug.

Remedy: Time to retune the carburetor settings and change spark plug.

4. Khad..khad..khachad..khachad..khad..khad... sound near engine in Self Starter models (electra 5s ). Prominent from front- left side of engine.

Reason: The mechanic told me this is normal behavior and no solution; also there is nothing to worry.

5. Thhakk.. thhakk...thhakk.. thhakk + tick ...tick...tick in parallel  sound (The noise is similar to that of a sewing machine being peddled) generally comes due to improper tightening of Tappets. This particular sound appears while shifting from 1st to 2nd gear. Sometimes similar sound may appear if trying to run BULL in 2nd or 3rd or 4th gear at a realtively low speed with a pillion.
   Remedy: Time for tappet adjustment.
6. metallic clanking tik-tik-tik.... kinda noise from engine head  . Generally due to PAV mechanism . I have live with this noise. No remedy till date.
7. If You hear single khattt.. sound just after applying brakes and when bike is about to stop or metallic kreeench .. sound , then it is due to rust or dust deposit inside rear drum brakes to due moisture etc . Time to get the rear drum brakes opened and cleaning.
8. Jhannn...jhannn...jhannn...kind of noise on some specific rpm/speed. Definitely a loose nut-bolt etc on any/some of your BULL's accessory or silencer.
9. Some strange metal sound on some specific rpm/speed. Check for some loose bolts for some accessories/chasis/engine or whatever nut bolt etc etc you can check with your bare eyes. Check for the gaps in between some accessories and the chasis/frame. Sometimes accessories like saree guard etc vibrate on some specific rpm and speeds. If you are not able to identify the source of such metallic noises or you dont see any such things then rush to some expert/reliable and good mechanic. Your BULL might be in trouble and need some money from you.