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After my blogs on performance parts, innovative accessories and Bullet mechanics I felt there was need for some good tutorials for Enfield UCE engine. How much ever I went through the net, I could not find any good channels that covered the basics tutorials for maintaining your Bullet. With that there came the need for the products that could help maintain your Bullet. So I have started this blog as a means for covering both these aspects. Tutorials for maintaining Bullet and Product reviews for tools that help in maintenance.

Thursday, March 10, 2016

Bullet Standard 500 carburetor (UCD33) Adjustment setting / tuning

Carburetor adjustment is an essential part of your Bull's maintenance.  Most mechanics nowadays will set your carb to extra rich setting as they have no idea how to get the optimum setting right. A carburetor that is set to rich setting will darken your spark plugs and may even foul them up prematurely. Also since the motorcycle is getting more fuel than air it causes unburnt fuel particles to come through exhaust leading to pollution and also low mileage. On the other side if a carb is wrongly set to lean it will result in low power. Also your engine will heat up more causing engine damage in the long run. Thus the importance of carburetor adjustment cannot be overstated.

How to check if you need Bullet Standard 500 carburetor (UCD33) Adjustment setting / tuning

The best way to check if your carb is running lean or rich is by looking at the condition of your spark plugs. In case your spark plugs have gone black then your carb is running rich. In case they are getting whitish then your carb is running lean and in case your spark plug is brownish yellow color then the carb is set to optimum setting. Some of the other symptoms of rich or lean carb settings is given in the last section of this tutorial

Tools required for Bullet Standard 500 carburetor (UCD33) Adjustment setting / tuning

1. Simple Screwdriver

 2. Tachometer/RPM meter (optional)

Important parts to know for Bullet Standard 500 carburetor (UCD33) Adjustment setting / tuning

1. Pilot/Mixture screw
2. Idle screw

Procedure before Bullet Standard 500 carburettor Adjustment setting / tuning

1. Engine has to be suitably warm before you start the tuning process. If the engine is not warmed properly it can lead to bad tuning. Before you start the adjustment it is essential that you take it out for 6-7 km ride. Try to ride in high speed so that the engine gets warmed up.
2. Before starting the tune also note down the current state of your pilot screw. Screw the pilot screw clockwise (with loose hands) till it does not screw anymore. Note the number of turns and then bring it back to its current position. Be very careful not to apply pressure at any point, or you may end up damaging the pilot screw seating. For noting the current position of the idle screw just note the number of screw threads showing above the bolt.

Procedure for Bullet Standard 500 carburetor (UCD33) Adjustment setting / tuning



1. Start the engine and turn idle screw slightly clockwise to increase the idle RPM. In case you have RPM meter then increase the Idle RPM to 1200-1400 RPM.
2. Now start turning the pilot screw clockwise in half turns. You can slightly scratch the topside of the pilot screw so that you can count the turns without getting confused.
3. As you keep turning the pilot screw the fuel mix will turn leaner and the engine will start skipping.
4. Now comes the tricky part. You have to stop turning just when you feel the engine is going to shut down. If the engine shuts down it will get very difficult to start it again without bringing the pilot screw to its original position. So ensure that you stop at the right time


5. This is the leanest setting your engine can have. Now start turning the pilot screw anti clockwise in half turns.
6. As you turn the pilot screw you will notice that engine sound will increase with the turns as the rpm increasses. People having RPM meter can see the RPM going up in their meter. Keep turning the pilot screw till you can hear the engine sound increasing.
7. Stop at the point where the engine sound does not change in spite of your turning the pilot screw. People with RPM meter can stop when the RPM stops increasing inspite of turning the screw. Usually this happens at 3-4 full turns.
8. Now start turning the idle screw button anti clockwise.
9. As before keep turning it till you feel that the engine is going to shut down
10. Set the idle screw quarter turn above that setting. In case you have RPM meter you can keep the idle at 800~1000 RPM.
11. That's it your carburetor is tuned.

Post Procedure for Bullet Standard 500 carburetor (UCD33) Adjustment setting / tuning

Go for a ride. Your bull should be performing better than before and should feel lighter.
However common problems that you may encounter in case of improper tuning are given below:
1. Motorcycle not starting normally but starts when choke is pulled.
The tuning is very lean. Turn the screw quarter turn clockwise and see if it gets resolved. If not turn it quarter more.
2. Motorcycle stalling whenever I am at idle
Idle screw RPM is tool low. Increase the idle screw RPM by turning idle screw clockwise in quarter turns.
3. Motorcycle running very hot
The tuning is lean. Turn the screw quarter turn clockwise and see if it gets resolved. If not turn it in  quarter turns till problem resolves.
4. Popping noise during deceleration
The tuning is lean. Turn the screw quarter turn clockwise and see if it gets resolved. If not turn it in  quarter turns till problem resolves.
5. Mileage has reduced drastically
Carb is running rich. Turn the screw quarter turn clockwise and see if it gets resolved. f not turn it in  quarter turns till problem resolves.
6. Exhaust is black and sooty
Carb is running rich. Turn the screw quarter turn clockwise and see if it gets resolved. f not turn it in  quarter turns till problem resolves.
7. Engine starts fine but power is less
Carb is running rich. Turn the screw quarter turn clockwise and see if it gets resolved. f not turn it in  quarter turns till problem resolves.

These are few of the problems that I can think of. In case you encounter some problem which cannot be resolved, promptly revert your carb to original settings noted at the start.


11 comments:

  1. plz check for popping sound... Turn the screw quarter turn clockwise and see if it gets resolved. If not turn it in quarter turns till problem resolves.
    Carb is running rich. Turn the screw quarter turn clockwise and see if it gets resolved. f not turn it in quarter turns till problem resolves.
    Carb is running rich. Turn the screw quarter turn clockwise and see if it gets resolved. f not turn it in quarter turns till problem resolves.
    ALL 3 ARE SAME

    ReplyDelete
  2. Hi Adamya, I need your opinion on an issue i am facing with my AVL 500 engine (Bullet Machismo 500).
    At times during riding, the engine suddenly slows down as if its lacking fuel... (it is similar to what happens when your petrol level goes into reserve...the sudden slowing down due to lack of fuel..). However, this happens even when the petrol is tank full. I took it to a mechanic who said that it has something to do with the fuel valves in the engine (!!!??). Also, i noticed that when i increase the idling of the engine (idling screw), this issue disappears. Can you please advice what is happening?

    thanks
    Ramesh

    ReplyDelete
    Replies
    1. Hi Ramesh,

      I am afraid this issue can't be resolved without having a complete lookover of your Bullet. As you mention that increasing the idling is resolving the issue. It means that engine is asking for more fuel and is underperforming. This can be due to worn out clutch plates or valve rods. Best take a second oponion from another mechanic as well to get a better idea.

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    2. i am facing same to same problem in my classic 350.
      did you got the solutions for this bro. please Reply.

      Delete
  3. I'm encountring knocking after I visited an authorized service center. Will DIY help in this case? Also, the engine is getting very hot and there's too much power now. In lower gears it looks like the engine is skipping.

    ReplyDelete
  4. Hey bro how u doin ? Ive sold my previos std 500 and bought a new one this time the colours like ur one . . . First things first the moment i got home i set up my air fuel mixture cause something wasnt feeling right the bikr had amazing pick up but wasnt pulling even tho im doing the whole between 40 and 50 kmph till the first 500kms service so when i tuned it it asked for 7 half turns exactlly as per ur video till the rpms stayed the same but guess what the company setting were only 4 half turns no wonder the strange feeling . . . Thats crazy man a std 500 and only 4 half turns i would screwed up the new engine if i didnt have to learn from ur video . . . Thanks man

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  5. what is the function of cable on the other side

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  6. I own classic350 UCE.Before few weeks there was the popping soung while decelerating, after the carb tuned with 6 turns the sound went off. But recently the sound appeared again i tuned to 7 turn..the sound is still occurring while decelerating. Help

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  7. Hi bro, I did this on my 1981 year RE bike. I got 2 complete revs in factory setting and I changed the revs to 1 and half by checking 4 times. Now, my bike performance increased. I have done this on 24th Dec and performance is good and went for a ride of 50kms. On 25th Dec I didn't ride my bike and while I starting my bike on Dec 26th, It's not starting. I turned the idle screw click-wise for acceleration and it started but, when ever I'm decelerating it is stopping. Smoke also coming more while accelerating. Previously, my bike is good with no defects. Could you help me ASAP?

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  8. My bullet 350 producing popping sound on deceleration

    ReplyDelete