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Old 24th June 2015, 22:34   #31
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Default Re: Throttle Position Switch of Thunderbird Twin-Spark UCE

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Originally Posted by adrian View Post
The shaft of the TPS should start moving the moment you start to twist the throttle and there is a yellow ring mark on the shaft, which should be visible at full throttle.

As to the fuel screw adjustment, please refer to ArizonaJim's post 1733 in the following thread

http://www.team-bhp.com/forum/motorb...eries-116.html (Royal Enfield Queries)
regards adrian
@adrian I fiddled with the TPS and set it up. I also set up the carb. Can you pls confirm if the visibility of yellow ring at WOT is correct?

I have attached a pic for you to judge. If possible pls post a pic of your bull my friend... Thank you.

Update
Even after trying multiple combinations I am experiencing the jerks while accelerating. The bike just skips a moment. Plz help with correct carb and TPS setting.
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Old 25th June 2015, 10:41   #32
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Default Re: Throttle Position Switch of Thunderbird Twin-Spark UCE

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Update
Even after trying multiple combinations I am experiencing the jerks while accelerating. The bike just skips a moment. Plz help with correct carb and TPS setting.
The TPS setting looks fine to me and is similar to the setting in my bullet. What is the throttle position at which the motorcycle misses ?

Before attempting to tune the carburetor the following things needs to be checked first

1. Remove and clean the air filter

2. Remove and clean the spark plugs and check the electrode gap. As per company specifications, it should be between .70mm to .80mm. Check the suppressor caps for dirt and check if the high tension lead connections are not loose.

3. Clean the fuel filter / ensure that you have clean fuel in the tank.

4. If possible, dismantle and clean the carburetor. Be very careful when you are dismantling the rubber diaphragm assembly.

5. If you are not at all sure of taking the carburetor apart, at least check that there are no vacuum leaks and that the carburetor atmosphere vents are clean and the rubber hoses are not pinched. Also, drain the float bowl of the carburetor using the brass screw that sits just above the thin overflow rubber tube.

6. Keep the fuel tap in the reserve position while tuning the carburetor. If the petrol level is depleted to a level where it would reach reserve, then adjusting the carburetor with the petrol tap in main would not give good results as the petrol flow to the carburetor will not be constant and would give the indications of motorcycle running lean and you would end up with a rich mixture by screwing out more of the mixture screw.

7. With everything stated above cleaned, reassembled and adjusted, start the motorcycle and bring it up to optimal engine temperature.

The rest of the procedure is as described by Arizonajim. Just keep in mind that we have a mixture control screw in the UCEs. Turning it in (clockwise) leans out the mixture and turning it out (anti clock wise) richens the mixture.

regards adrian

Last edited by adrian : 25th June 2015 at 10:47.
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Old 25th June 2015, 15:00   #33
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Default Re: Throttle Position Switch of Thunderbird Twin-Spark UCE

Hi.. The bull jerks intermittently. When I rev gradually the jerk is minimal to almost nil. When I rev a little hard it jerks. It jerks immediately beyond the free play of throttle lever.

The carb settings I tried were 1.5,1.75, 2.25 and 2.5
The TPS was set to 40% of throttle lever engagement, without any play, etc..

Sometimes it worked beautifully when I was alone on the bike but jerks with a pillion.
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Old 25th June 2015, 16:06   #34
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Default Re: Throttle Position Switch of Thunderbird Twin-Spark UCE

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It jerks immediately beyond the free play of throttle lever.
You have a lean pilot circuit.

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Originally Posted by petrolhead_chn View Post
The carb settings I tried were 1.5,1.75, 2.25 and 2.5
Buddy, there are no preset values of the fuel screw. Follow the correct procedure of tuning and determine the turns of the fuel screw. The company specified turns is 3 +/- 1 turn and advises to start tuning with the fuel screw at 3 full turns. Now this is just a suggestion and the actual turns may vary based on elevation and climate. My bullet's fuel screw is set at 5 and 1/2 turns as of now and have gone out as far as 6 turns in cold climates (I get a mileage of around 38 kmpl in city).

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Sometimes it worked beautifully when I was alone on the bike but jerks with a pillion.
Knocking on load - again a symptom of lean fuel mixture. Remember that if your machine is tuned perfectly, these will show :

1.No backfire either from the carburetor or exhaust
2. No hanging up of idle
3. The carburetor float body will be cold to touch
4.water droplets from the exhaust on a humid day

regards adrian

Last edited by adrian : 25th June 2015 at 16:09.
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Old 25th June 2015, 16:54   #35
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Default Re: Throttle Position Switch of Thunderbird Twin-Spark UCE

Lean pilot circuit - lean mixture is it?

I am going to clean carb and reset. Thank you very much Adrian. Will keep you informed.

BTW, any idea on what would be the oil level that should show up when engine is running, idling and when cold. Just curious as it confusing bro
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Old 26th June 2015, 10:40   #36
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Default Re: Throttle Position Switch of Thunderbird Twin-Spark UCE

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Originally Posted by petrolhead_chn View Post
Lean pilot circuit - lean mixture is it?
Lean pilot circuit = lean air fuel mixture in the pilot circuit which governs the air fuel ratio during starting and just off throttle positions.

Quote:
Originally Posted by petrolhead_chn View Post

I am going to clean carb and reset.
Be very careful when dismantling the constant velocity carburetor. Learn the procedure well by referring to the workshop manual and the videos available in the internet. Slight mis alignments - especially when replacing the rubber diaphragm will cause vacuum leaks.
Don't spray cleaning agents on the rubber diaphragm.
Fully understand the order of things while reassembling (Photographs would help a lot). For eg : Do not interchange the position of metal washer and o ring on the fuel screw.

Quote:
Originally Posted by petrolhead_chn View Post
BTW, any idea on what would be the oil level that should show up when engine is running, idling and when cold. Just curious as it confusing bro
As per company specifications, on a warm engine with the motorcycle in center stand on a level surface, after giving sufficient time (say 20 minutes) for the oil to drain back to the sump, the oil level should be between the full and low marks.

The oil window will be fully filled with the engine running.

On a cold morning, the oil level might hover around the low level marking.

Note : The above said oil levels will show only if you fill the oil carefully and correctly. The bullets that are getting their oil changed at the RE ASS shows a fully filled sight glass, be it in the morning or with a warmed engine. How do I know - I did all my free services at the RE ASS. Been there done that.
regards adrian
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Old 27th June 2015, 01:03   #37
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Default Re: Throttle Position Switch of Thunderbird Twin-Spark UCE

Thank you again Adrian. After tuning carb the jerks have reduced. But I still feel slight jerks now and then. I will keep you updated😊

I was actually checking almost all UCE engines in my office's parking lot for TPS setting. The security guards almost came closer to me and watched what I was upto which I did not realize. When I did realize I just put the phone to my ears and walked away casually pretending to be ignorant.😃 phew!
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Old 28th August 2016, 13:36   #38
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Default Re: What is inside my Throttle Position Switch

I thought of starting a new thread, but since the whole hustle of how to adjust TPS was taken up and concentrated in TGO's thread, I finally decided to post the solution here itself. I will just let the picture do the talking..
Read the previous posts in this thread and co-relate with the pictures and you will know how to adjust the TPS

Throttle Position Switch of Thunderbird Twin-Spark UCE-1.jpg
Throttle Position Switch of Thunderbird Twin-Spark UCE-2.jpg
Throttle Position Switch of Thunderbird Twin-Spark UCE-3.jpg
Throttle Position Switch of Thunderbird Twin-Spark UCE-4.jpg
Throttle Position Switch of Thunderbird Twin-Spark UCE-5.jpg
Throttle Position Switch of Thunderbird Twin-Spark UCE-6.jpg
Throttle Position Switch of Thunderbird Twin-Spark UCE-7.jpg
Throttle Position Switch of Thunderbird Twin-Spark UCE-8.jpg
Throttle Position Switch of Thunderbird Twin-Spark UCE-9.jpg
Throttle Position Switch of Thunderbird Twin-Spark UCE-10.jpg

Last edited by adrian : 28th August 2016 at 13:37.
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Old 28th August 2016, 13:47   #39
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Default Re: Throttle Position Switch of Thunderbird Twin-Spark UCE

Pictures continued..

Throttle Position Switch of Thunderbird Twin-Spark UCE-11.jpg

Throttle Position Switch of Thunderbird Twin-Spark UCE-12.jpg

Throttle Position Switch of Thunderbird Twin-Spark UCE-13.jpg

Throttle Position Switch of Thunderbird Twin-Spark UCE-14.jpg

Throttle Position Switch of Thunderbird Twin-Spark UCE-15.jpg

Throttle Position Switch of Thunderbird Twin-Spark UCE-16.jpg

What I have done now is the following
1. Adjusted the slack in the throttle grip as per specification
2. Marked the throttle increments and identified the 40% throttle position
3. Unplugged the TPS cable from the TCI unit
4. Gently put the leads of the continuity tester to the two sockets in the TPS output wire.
5. Rolled on the throttle and ensured that the continuity tester lights up just after the throttle is rolled after the 40% mark. If not fine tune by adjusting the cable slack at the TPS unit.

Note : There is a spring in the shaft which returns the slider back to its position when the throttle is released. I misplaced it somewhere and hence it is not in the photograph
There is no need for the ignition switch to be in 'ON' position for this adjustment (Keep the key in your pocket).
Caution : Never take your TPS unit apart unless you plan to replace it with new. As you can see the chances of the TPS unit getting damaged is rare as it has simple parts and the only possible damage is the wear caused by the slider moving over the printed circuit board.

regards adrian

Last edited by adrian : 28th August 2016 at 13:57.
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Old 28th August 2016, 19:31   #40
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Default Re: Throttle Position Switch of Thunderbird Twin-Spark UCE

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2. Marked the throttle increments and identified the 40% throttle position
Throttle is far more sensitive near idle than near wot. If you could mark the 40% mark on the twist grip, and find out the speed and corresponding engine rpm when in fifth, it would be nice.

Can't believe I'm the first to thank you.

Regards
Sutripta
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Old 29th August 2016, 13:07   #41
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Default Re: Throttle Position Switch of Thunderbird Twin-Spark UCE

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Originally Posted by Sutripta View Post
Throttle is far more sensitive near idle than near wot. If you could mark the 40% mark on the twist grip, and find out the speed and corresponding engine rpm when in fifth, it would be nice.

Can't believe I'm the first to thank you.

Regards
Sutripta
I ride a Standard 350 UCE which is not equipped with a tachometer. So reading the rpm with reference to throttle position is not possible unless I add an inductance tachometer. So for the time being, members with Thunderbird 350s can help.
regards adrian
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