Triumphrat

jimmyj900

Look very carefully at the connectors on the ignition coil.

The low voltage terminals can become corroded and are easily bent out of good contact.

Also, the rubber boots on the high voltage connectors will sometimes slide too far on the wire when removing the plug wires. This will cause the connector to separate and arc inside the rubber boot.

Make sure you pull the boot back a bit before you connect the plug wires so that there's a good connection before you slide the boot on.

Jim

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polex

I removed the carburetors for the second time and I measured the compression:
Cylinder 1: 11.8 KPa
Cylinder 2: 11.5 KPa
Cylinder 3: 12.0 KPa
The value was high but the measure was made without the carburetors.

I exchanged the following parts between carburetor 1 and 3:
1) main jet and holder
2) pilot jet
3) pilot screw and spring
4) float
5) float valve
6) choke valve

Now the problem is moved to cylinder 1.
If I remove the spark plug cable from cylinder 1 the engine runs like the cable is inserted (only at the idle).
This happened to cylinder 3 before exchanging the parts.
I restricted the problem to some parts of the carburetor.

Mainly the parts that I exchanged are not damaged and they are pretty clean. Then I don't understand why those parts cause a problem.

Referring to this web site:
http://faq.ninja250.org/wiki/How_a_c...arbs_explained
I noticed a collar between main jet holder and the carburetor.

In the bikebandit.com:
http://www.bikebandit.com/houseofmot...m6894sch512877
I noticed a collar between the main jet and the holder.

Should I find the collar in my Keihin carbs ?
Does the bikebandit reflect the correct carburetor parts for Legend TT ?
Why is it missed the pilot jet ?

My VIN ends with 102063.

I would like to use "colortune", it is a transparent spark plug used to tune the pilot screw.

Have you ever used this tool ?

Thank You very much for your support.

jimmyj900

That must be KPa x 100 so 12KPa x 100 x .145 = 174 psi.

Looks pretty good -- within 5%

Look at the pilot jet bore with a strong light and strong magnifier.

I had a similar problem one time. When I held the pilot jet up to the light I could see light through the bore and thought it was OK. When I looked with the magnifier I could see a film of varnish covering the bore! It passed light but was like a layer of clear plastic blocking fuel flow.

If you are looking at item '8' that's the needle jet and it usually stays in the carburetor body when you remove the main jet and holder/emulsion tube.

You should be able to see it inside the carburetor bore sticking up about 1mm or so.

If missing you'll have VERY rich operation!

It seems to be OK.

The BikeBandit parts pictures are from the Triumph microfiche and apparently Triumph doesn't offer different pilot jets.

Sorry, never tried Colortune.


Check that pilot jet!


Jim

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polex

The compression ratio of the legend TT should be 10:1, then I expected about 10 KPa compression.
I sprayed the carburetor cleaner inside the jet, but the spray pipe did not fit perfectly the jet and it was remained partially clogged.
Mainly this is the only possible cause which justify the symptoms.
Have you ever removed the bowl and the jet without removing the carbs ?
The collar is the copper hole for the needle jet. It is viewable when you remove the diaphragm.
Is it correct ?
I removed the main jet and holder together. Probably the collar was still remain inside the carburetor and I did not noticed it.
The picture:
http://www.bikebandit.com/houseofmot...m6894sch512877
do not show the holder.
I understand that the collar is on the top of the holder (between the holder and the carburetor) it is not inside the holder (between the jet and the holder).
Is it correct ?

Thank you very much Jim.

jimmyj900

Pretty much. You need to remove the pilot jets, soak them in carb or brake cleaner for a half hour or more and then scrub them out with a piece of stranded copper wire. The wire makes a good brush and won't damage the brass jet.

Use a magnifying glass! You should be able to see the machining lines in the jets from when they were drilled at the factory.

Never. The chance of doing damage to the carbs is a much larger inconvenience than removing them and doing it right.

Correct. From the diaphragm side it looks like a brass ring in the carburator throat. It's a light press fit and normally held in by the top end of the emulsion tube, so finger pressure will usually push it out.



Yes, the needle jet sits on top of the main jet holder/emulsion tube and and goes through the carb body into the venturi.

Jim

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polex

I discovered the problem.
Comparing a bad pilot jet with a good one I noticed that the hole was bigger.
Probably the jet was drilled.
I ordered all jets (3 main jets and 3 pilot jets).
I reassembled the carburetors using the new jets and now all the cylinders run at the idle.
I ride for some miles and the throttle response is very good, no hesitation at any rpm.
The first estimated mileage with the new jets is 46 MPG.
There still only a minor problem: when I release the throttle @ 3000 rpm I hear some small shot from the exhaust.
What does it means ?
Rich mixture or lead mixture ?
Probably I have to tune the pilot screws.
What is the best practice for tuning the pilot screws ?

jimmyj900

That's wierd.

It's normal for these bikes to pop or crackle during engine braking (overrunning) so if it's happening then, don't worry about it.

The consensus setting for the mixture screws is 2-1/2 turns.


Congratulations on getting your bike running properly!

Jim

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polex

I think 46 MPG is a very good mileage indicating a good carburetor tune-up.
I read about 50 MPG, but I think that it is little bit exaggerated.
Thank you very much Jim.
I have never solved the problem without you support.

It is a wise approach.
If I followed this approach I solved the problem faster.

Thank you to all.