PDA

View Full Version : Triumph ?'s on clutch adjustment and stalling when downshifting.



SacredSteel63
07-22-2012, 5:27 PM
I just picked up this 67 Triumph T120 with a rebuilt motor, carb, brakes, etc. It starts good and runs great but it wants to stall when I down shift, mostly when going from second to first. Sometimes I catch it by reving it a little but sometimes I miss it and it stalls. Any idea what to look at? Could it be the way I'm riding it? The jets are main - 230, needle jet - 622/128. Single carb.

Also, a clutch question. I looked at the manual and saw a short video on Lowbrow customs web site on adjusting the clutch and I followed the procedure. The clutch lever need to be almost all the way out before it engages. On my Harley I can adjust it so it engages almost as soon as I start letting up on the lever. Is this normal on the old Triumphs?

Thanks.

http://i273.photobucket.com/albums/jj218/60tbirdrick/0722121024.jpg
http://i273.photobucket.com/albums/jj218/60tbirdrick/0722121024a.jpg

RetroRob
07-22-2012, 7:20 PM
Should be able to adjust the clutch at the gearbox spits easier to feather it. I don't know much about carb jets so I'm curious about your stalling also.

Triumph803
07-22-2012, 7:37 PM
Sac steel, the early concentric carbs used on the 67 and 68 triumphs had the pilot jet screwed into the bottom of the carb body,they changed it to a pressed in pilot jet inside the body to stop exactly the stalling you have described. so the fix is a later pressed in jet carb body. You can check if you have an early carb by removing the float bowl and look for the screwed in pilot jet. Jack

SacredSteel63
07-23-2012, 4:33 AM
Sac steel, the early concentric carbs used on the 67 and 68 triumphs had the pilot jet screwed into the bottom of the carb body,they changed it to a pressed in pilot jet inside the body to stop exactly the stalling you have described. so the fix is a later pressed in jet carb body. You can check if you have an early carb by removing the float bowl and look for the screwed in pilot jet. Jack


Thanks, so if I have the early model is there a kit available to modify it or do I need to buy a new one?

SacredSteel63
07-23-2012, 5:37 AM
This is what I have. It appears as though I have the pressed in pilot. So how do you clean the pilot jet if it's pressed in?

http://i273.photobucket.com/albums/jj218/60tbirdrick/0723120730.jpg
http://i273.photobucket.com/albums/jj218/60tbirdrick/0723120727.jpg

Torch
07-23-2012, 8:52 AM
it could also be in and around 1968 they also put the pilot jet in the mouth of the carb. if it's there, you should be able to see brass jet under the air cleaner, this was also a one year only failed attempt of a good working pilot circuit.
the only fix for this too is a new carb.

If it's a pressed in (normal) jet that is plugged it could be causing this, the easy way to tell is......with the bike idling turn the jet all the way in and it should change the idling drastically even to the point of stalling, and then when you turn the screw out to about 1 1/2 turn out it should raise the idle speed back up. it you get no change in idle then the jet is plugged.
To clear the jet we sell this tool that is CAREFULLY inserted into the screw port and hand twisted until the jet clears out then some carb cleaner shot through it untill it comes shooting out of the tickler plunger.
Here is a picture of the pilot jet tool.......
http://i457.photobucket.com/albums/qq294/A1dunn/Amalpilottool.jpg

SacredSteel63
07-23-2012, 10:52 AM
Torch,
When you say "turn the jet all the way in" are you referring to the air mixture screw next to the idle adjustment? I believe the pilot jet is behind that screw. I did what you said and stalls when the screw is turned in all the way and idle increases when turned back out. It was backed out about 1 turn. Also, I'm wondering if my throttle cable may have something to do with it. I noticed when i move the cable around with my fingers, it changes the idle up and down and sometimes causing it to stall.

Torch
07-23-2012, 11:41 AM
Torch,
When you say "turn the jet all the way in" are you referring to the air mixture screw next to the idle adjustment? I believe the pilot jet is behind that screw. I did what you said and stalls when the screw is turned in all the way and idle increases when turned back out. It was backed out about 1 turn. Also, I'm wondering if my throttle cable may have something to do with it. I noticed when i move the cable around with my fingers, it changes the idle up and down and sometimes causing it to stall.
ok here is a quick little Amal carb course...
yes the pilot mixture screw goes horizontally (flat sideways )into the carb, and the idle speed screw goes diagonally (at an angle) up into the carb.
If you get a reaction out of the idle by turning the mixture screw in, then the pilot circuit is working fine,
the cable should not be the idle speed control. only the diagonal idle speed screw that holds the slide up for the proper speed should do this.
so start by slackening off all your throttle cable adjustments, then using your finger on the slide turn back off the speed screw all the way until the slide is completely closed, then turn the adjust the idle speed screw up until it touches the slide and then about one turn more.
the mixture screw will be at the richest mixture when it's all the way in and the leanest mixture when its all the way out. ( yes it's opposite of a normal carb ).
the mixture should be about 1 1/2 turns out from bottom and the more it turns out the leaner the mixture, turn it out until you get a clean running idle and check it by giving it a rev. if it's too lean it will pop then rev, if it does that turn it in until it revs without popping and adjust the speed screw till you get it to idle at a good rpm.

I hope that helps, Tony

SacredSteel63
07-23-2012, 2:14 PM
Thanks Tony, I'll give that a try.

SacredSteel63
08-01-2012, 7:12 PM
Problem solved:cheersmate:
Bought a new 930 carb with a 200 main and #3 slide, Put the 250 jet in from the old carb (it was a new jet) and that seemed to solve the stalling when stopping problem. I made a #3 slide into a 3.5 like Torch said but it was real hard to start. Not sure if that was the problem but I put the new #3 slide back in and starts on first kick.

Going riding tomorrow:clap for you:

RetroRob
08-01-2012, 8:37 PM
250 jet may bee too much, see if you plugs get sooty, might want a 220 or so.

SacredSteel63
08-02-2012, 3:37 AM
I thought about that but changing out jets is easy enough. At least I fixed my stalling issue.

Torch
08-02-2012, 8:43 AM
Problem solved:cheersmate:
Bought a new 930 carb with a 200 main and #3 slide, Put the 250 jet in from the old carb (it was a new jet) and that seemed to solve the stalling when stopping problem. I made a #3 slide into a 3.5 like Torch said but it was real hard to start. Not sure if that was the problem but I put the new #3 slide back in and starts on first kick.

Going riding tomorrow:clap for you:

the 3.5 slide and the 250 jet will likely make it way too rich, do one or the other,
the 3.5 slide fattens up the mixture in low and mid range.
the 250 main jet is pretty big and will make it run real rich.
try putting a 210-220 or 230 jet in there with the 3.5 slide

SacredSteel63
08-02-2012, 12:31 PM
Right now I have a 3 slide and 250 jet. Rode for about 15 miles today and checked the plugs. no soot on the plugs. Air mixture screw out one turn. Seems to be fine the way it is although I may try a 240 jet to see if there is any difference

Torch, What is a normal temp for these old triumphs? After my ride I took a temp gun to the heads and read about 275-280. Is that normal?

Thanks

Torch
08-03-2012, 12:36 PM
Right now I have a 3 slide and 250 jet. Rode for about 15 miles today and checked the plugs. no soot on the plugs. Air mixture screw out one turn. Seems to be fine the way it is although I may try a 240 jet to see if there is any difference

Torch, What is a normal temp for these old triumphs? After my ride I took a temp gun to the heads and read about 275-280. Is that normal?

Thanks

the temp is right there, don't worry about that.
The 3.0 slide will run leaner than a 3.5 slide and the 250 main is trying to compensate for that, as well as the 1.0 turn out on the pilot mixture is also trying to fatten up the mixture to get around the lean slide issue.
What it affects mainly is all the running conditions at low and intermediate speeds trying to richen it up and then at full throttle it will end up being too rich,
But of coarse this all depends on the slide being a nice tight fit, if it's sloppy then you need to put bigger jets in there to make up for all the air bled around the slide.

SacredSteel63
08-03-2012, 5:30 PM
Thanks again Torch. I set my carb up the way you advised with a 230 main and 3.5 slide and seems good now. Hopefully it will stay that way for awhile.