set the idle on my t140 its okay then as soon as i rev it up the tickover rises up .the cable seem okay carbs cleaned out in ultra sonic tank .what is the correct revs for the tickover. maybe i am going to low. no rev counter on my bike but can get a lend of a digital one to set it. all standard jets, needle set in the second groove AMAL 900 carbs on it with bell mouths cheers for any help
Not sure if Bushmans still advocates syncing with WOT, but here's a small blurb about syncing from John Healy:
In my youth I figured it was best to start throttle cable adjustment at full throttle just like Bushman recommends. My logic, driven by what have been a youthful bursts of testosterone, demanded it. Often we were fresh from the pages of Irving's "Tuning for Speed" and wanted all from our engines.
Then one day watching a competitor at the track adjust his cables it hit me: It was all about "percentage of error," and you wanted the error where it made the least difference.
If there is going to be any error in how the cables lift the slide you want it where it has the least effect. That is at wide open throttle. Bushman's system insures that if there is a problem it will be where it will have the greatest effect upon the percentage of error (POE), and thus effect upon how the carburetor operates: Low throttle openings.
Any error in slide movement, or height, will have the greatest effect upon carburetor performance at low throttle openings. So it is better to start from the bottom, and let any error be at or near full throttle where any slight difference in height will have the least effect upon the POE.
1. Unscrew the throttle stops so they allow the slide to hit the bottom of the carburetor body. 2. Using the two cable adjusters get both slides to lift off the bottom of the bottom of the body at exactly the same time when you open the throttle. When you let go of the throttle you should here a single click. Not click, click!! 3. Place a finger on the side of the slide through the venturi and turn the throttle stop until you JUST feel it lifting the slide. Then turn the throttle stop screw in 3/4's of a turn. Do the same to the other carburetor. 4. Double check that both cables have a bit of free play so that the throttle turns a bit before it starts to lift the slides (important!!). 5. Set the pilot air screw at 1 1/2 turns out. 6. Make final adjustments making small (1/8 turn) adjustments EQUALLY to each throttle stop. When you open the throttle and let the slides drop you should only hear a single click... again not click,click. 7. While the throttle stop adjustments should end up even, there can be slight variations in the final setting of the pilot air screws.
And when both sides of the motor are pulling equally at low to medium throttle openings it will seem to vibrate less!
Now you have adjusted out any variations at low throttle openings and moved any variations in cable routing or number of bends in each cable to larger throttle openings where any variant will be a much smaller POE. And at WFO the slides are out of the venturi and have no effect on all this.
Or you could use a 2 into 1 cable arrangement and have fewer problems!
'77 T140J "Vintage Bike". What's in your garage?
"The paying customer is always right."
Fitting round pegs into square holes since 1961...
what should the revs be at tick over still getting the same problem ,maybe i am going to low . also my rear discbrake does not feel rite should there be a lot of travel on the pedal or should you just have to dab the pedal cheers again for any help
These things don't need to idle like a Harley, 1000-1100 is where I usually shoot for when engine is fully warmed up. Probably need to partially withdraw the axle bolt so the rear caliper hangs down with the bleed nipple in the highest possible position. Then bleed brake. Will need to remove left muffler to get axle out. IMHO the t140 rear brake system is one of the most f'd up designs in motorcycle history. I'm struggling with mine right now. I'm going to have to do a large paint touch up from spilled brake fluid.
I know on Nortons the typical problem with inconsisten idle is worn slides. Does the same occur on Triumphs?
I know last year I replaced ALL my old worn AMAL slides with the new hard anodized slides. It definatly improved my Norton and the action is smoother on my Trophy. Could not tell a difference on the tiger though.
Any air leak around a worn slide will give wonky idle. tell tale sign is to just barely take up the slack on the throttle and you can actually detect an idle dip before it will start to pick up.