Pimping my Ride
Posted by Exile on January 15, 2014
Or, how to upgrade the carburettor and fit a new air filter.
One thing you quickly learn about owning a motorcycle is, that you need to improve it on the performance side of life. Then you need to improve the aesthetic appeal of the thing. I got it the wrong way round. I merely wanted to get a sporty looking air filter fitted to Thumper, my Royal Enfield Bullet. I ended up doing a job I never thought I was going to be capable of.
The old air filter was a complicated affair that incorporated an otherwise useful toolbox fitted to the machine and a square box with another filter fitted which finally fed the carburettor with air. I wanted to fit a nice little sporty filter that would allow me to use the toolbox as it was intended (by my reckoning) and get rid of the intermediary box. I’d seen the part and a snazzy little chrome shroud to protect the sporty filter in a suppliers catalogue and immediately ordered both.
I am a member of a forum which busies itself with all things Royal Enfield and, as bragging rights are valid on this forum, I happily told everyone that I was about to take on this rebuild. That’s when my problems began to take form.
I was told, by many, that simply doing away with the existing filter was OK, but I would have to re-jet the carburettor to allow for the extra available air that would now flow freely into said carburettor. News to me, I thought, but they were insistent. I rang the suppliers the following day. By now, my initial order was on it’s way so a new order went in for the recommended parts that we (my supplier and I) finally agreed upon. I was pointed at some instructional notes to be found on the forum website. ‘There’s all the information you will need.’ said the more than helpful chap on the other end of the telephone line. The supplier actually hosts the forum, so he should know. I dug into the internet and found the relevant technical notes.
Three days later, all the parts arrived. I unpacked the little boxes with trembling hands. A collection of bits of machined brass and the filter and shroud plus some rubber like discs to blank off the holes in the toolbox that will be left after I remove the old filter tubing.
Off to the shed where Thumper lives then Exile… and start dismantling your beloved machine.
I removed the square box and all the bits that held it in place, remembering where they came from in case I need to reverse the process. I removed all the rubber tubes that carry the air through the existing filters. I removed the fuel line. I then removed the carburettor, which involved screwing the top off and partially dismantling the assembly. All very worrying stuff for the novice. But, eventually, there I was with a carburettor in my hands and the bike in bits around me.
The internal organs of the carburettor are fragile, many and tiny. I decided to take the thing into the living room where I could sit and swap the jets, according to and following the technical notes, without having to freeze my ass off in the shed. Cold fingers don’t handle tiny parts well and dropping one would probably mean it would be lost forever. I have a large white board in my cellar. Ideal for this sort of job, I thought. So I laid it on the dining table and set the carby down. Screwdriver at the ready, I set to work.
I stripped the carby, found and changed all the jets and reassembled the thing in under a quarter of an hour. Sometimes, I even impress myself! I even found out that the choke lever wasn’t working properly due to a loose locking device. So I fixed that too while I was up to my elbows in tools.
Back to the shed once again…
Replacing the thing didn’t take long either. The new filter and shroud fit directly onto the carburettor which fits directly onto the machine. I replaced the fuel line, set the carburettor to it’s recommended start settings (it will need final adjustment for tuning purposes) and decided to fire the thing up.
Keys, ignition, fuel and choke. And kick. Three times kick and Thumper jumped to life with a throaty roar.
The roar was from the new air intake. One can hear the engine sucking pints of the stuff down its greedy neck.
Man, it sounds good! Can’t wait to get him out on the road again…