Triumphrat

quagmire · 08-30-2006

I ran the TR6 today, got the engine good and hot and I will let it cool down tonight and retorque tomorrow. While I was running it I noticed that the bike would only idle if the choke was on (choke slide down in the carb and no tension on the choke cable) Mixture screw was about 1 3/4 to 2 turns out when I noticed the revs slightly increase. If I'm riding the bike under throttle I can raise the choke and the bike is ok, but when I stop it stalls.

Tomorrow, after I re-torque everything I'm going to check the valve clearances and put a timing light an it again to make sure it's OK ( I have a boyer on it) then where do I go??? Shouldn't I be able to start the bike without having the choke on? Or will it always need to warm up. I looked at my carb throttle and jets and they are standard according to my manual: main jet 230, needle position 2.

peintremondain · 08-30-2006

according that timing is ok you should proceed like this :1.warm the motor(10 miles )
2.stop and take the choke off and turn the stop screw in a few turn say two and restart the motor :it should be starting!
if not turn more in the stop screw etc.
3. once the motor running at fast iddle(1500 2000 rpm) play with the air screw in and out and try to determine when you get the higher rpm :do it slowly and make small increment at a time and wait a few second after every increment or deccrement .when you have determined the highiest rotation speed it mean that you have the correct air fuel mixture.
4.now you can decrease the iddle speed to around 800-1000 rpm
5.when the motor is cold you don't really need the choke to start:just flood the carb by tickling and with a small opening of throttle it should start(must of us take off the whole choke mechanism as it can be closing alone with vibes)
hope it helps!!!
ben

TripleGuy · 08-31-2006

Hi, it sounds like the idle circuit is blocked, if this is the case you will have to clean out the idle jet.
There is a very good nine page carb tuning secrets that explains what, why and how at:-

http://www.jba.bc.ca/Bushmans%20Carb%20Tuning.html

Well worth printing up, I had mine laminated.

HTH TripleGuy

Mecchanica · 08-31-2006

To relieve a stubborn plug in the idle jet, remove the idle adjuster screw. Take an old throttle cable, cut off an end and ravel the wires. Use one wire and use it to roto-rooter the jet, gently, using some carb cleaner in a spray can to ease out the gas residue (brown, gooey crud). Blow dry. Then take some muriatic acid or OSPHO in a syringe and force it through the passages. Note the two small holes in the bore at the rear (engine side) of the carb body. This dissolves the oxides and carbonates (white crud). You can soak the carb parts in a dilute acid solution and get them really clean. Rinse thoroughly in a bicarbonate solution, blow dry, and wash down with a light oil or WD-40 to seal the metal against further corrosion. Reassemble. Adjust. Ride.

quagmire · 08-31-2006

I'm beginning to think it is my idle jet. I ran the bike for 7 miles today and when traveling I can take the choke off and the bike responds beautifully. As soon as I slow down, or pull in the clutch and let the bike idle it quits.

This weekends project: Carb cleaning. :hammer:

I'll keep you posted.

quagmire · 09-01-2006

OK here is the latest. I took the carb apart and fished some wire thru the idle jet and the down the hole from within the carb body. I blew tons of compressed air and carb cleaner thru the idle mixture screw opening and a strong stream of carb cleaner came thru the little holes in the carb body. so Can I assume that all the passageways are clean?

Now, I double cheacked my jet: 230 main jet and 3 1/2 cutaway. Interestingly my bike with an extra 250 main jet. I also noticed that my needle position was on the bottom most notch. So before I reassemble this thing, what would people do?

I re-timed the boyer with a strobe today and with the bike at 4000rpm's the timing is right on. Also I noticed that my plugs are black, but this doesn't supprise me as the only way I can get the bike to idle is with the choke on.

So what settings would people start with?

jimballard · 09-01-2006

Hi Quag,

I've got my needle set on the bottom notch as well; figured that a little extra fuel won't hurt, especially with today's lousy gasolines. I idle mine at 1,000 rpm and I adjust the mixture to get the best idle speed along with the least vibration (not always at the fastest idle mixture, oddly enough). Is your advance mechanism working properly, or are you using electronic ignition?

Hope to see you at the meet....BIA meeting on Friday the 8th if you're interested: Jim

quagmire · 09-01-2006

OK Jim, I need to poke fun at you. Come down and I'll give you an eye exam:

Quote:

I re-timed the boyer with a strobe today

:-D

TripleGuy · 09-01-2006

Hi,
Right so the idle circuit is clean and all obstructions removed, next set the main jet needle clip onto the centre undercut/groove.
Take your bike to an open road with an incline so the engine has to pull, give it a good run up the incline, stop and check plug colour if its light grey/white you need to raise the main needle by putting the needle clip in the next undercut/groove DOWN.
I doubt you will have to do this as all my Triumph's run on the centre groove position and give a plug colour of light brown.
Enjoy riding your TR6 the weather here in Oz is great and the weekend will be spent on the Trident.

Ride safe, stay upright.
TripleGuy

Mecchanica · 09-03-2006

There are early and late concentric configurations. The early had a shorter main jet holder and used the three ID ring (not the clip grooves, shallower rings above them) and the later used the longer mainjet holder and the shorter two ID ring needle. The early carbs had a needle jet that doesn't have the air bleed holes cross drilled in the hex flats. Later ones have the bleed holes.
It isn't uncommon to have the needle push up into the spring and get hung up when installing a slide in a TR6. The needle can hang up on the edge of the needle jet. The best way to install it is with the air filter chrome ring off, then you can use a finger to align it.