neddle/vaccume slide problems?

[Social D 13]

I hope I'm calling it the right thing, but the rubber diaphram and the long celendrical holder of my needles is what I'm referrin to , which are in the top portion of my carbs.
Visually, I don't see any issues w them, but if there were some issues, how would my bike react?
I've cleaned and replaced my main and pilot jets, did my best to clean the carbs and checked for air leaks and I'm still getting hesitation from take off.
It seems that either its running on 1 cylinder or its not getting enough gas. I feel and hear that sputtering ( like when your going fast and your bike tells you that its time to switch to reserve).
I tightened up my carb rubbers and the nipples and when I was toying w the slides, there was resistance when I pushed up but it seemed to lose resistance for like 1 or 2mm and then resistance would kick back in. Seems when it open the throttle a little, either it gives and doesn't give gas or the bike is fuel starved. I've opened the carbs and I properly stored the bike over the winter- went through 2 tank full of seafoam.....
So I'm looking @ the slides but not sure what a torn or leaky slide and the rubber diaphram would feel like- 04 thrux, 7900 miles/ I'm the lucky 2nd owner.

 

[Delbert]

The carbs on these bike are pretty reliable, I would first check other possibilities before tearing into carbs. There is hesitation due to fact these carbs are vacuum/cable operated. Best check is to remove both spark plugs. If they look same then it's electrical. If one is black and wet then you have fuel problem, and would look to carb for problem. If one plug(s) is white then you're running LEAN and need to enrichen that circuit. Usually 42 to 45 is max for idle to mid-range and 122 to 130 should work for upper end and these also depend on altitude of living and where you normally operate your bike. Nobody runs wide open all the time. Mid range kinda uses both these jets you install and operates between them on it's own circuit, along with how open the slides are according to throttle position sensor. Some people have disconnected TPS and saw no ill effects when they tested or replaced carbs with performance type carbs.
The coils are notorious for giving a carb type feeling when they get warmed up and start to break down when going bad. There's really no way to test except by replacing coil with coil that positively works.
The ignition trigger sensor is another possibility that gives what feels like carburator type troubles when it breaks down. There is a test for this but I don't know what readings should be. I've just replaced mine and troubles stopped.
There also is a micro filter in T-section between carbs that can become plugged over time, but you would have all sorts of problems, even at starting or idle if this was the culpruit. If in that area just pull out and toss away and replace with good inline fuel filter.
If after these tests and nothing happens, then you may have some grit/crud in one of the carburator circuits and it must be taken apart and cleaned/washed/blowed out and reassembled. Don't forget the cap diaphram on carburator is oriented a certain way to work and must not be pinched when reassembling. Hold up,(with light behind diaphram) to determine if there's a pin hole in it where there shouldn't be any holes. Lots of stuff to look at, but you'll get to know your cycle. Good luck. As to your question about diaphram being bad, what yould happen is when you cracked the throttle(even just to 2000 RPMs and hold, you would hear a flucuation as motor would try to compensate with RPMs to correct as carburator slide would go up and down with vacuum leak. To see this you would need to remove air box and watch both carbs at same time to see one carb holding slide(under vacuum) while other slide would open/close as you gain vacuum and loose vacuum. There's thousands of us that haven't touched the top of carbs with thousands of miles on bikes(except for needle shims) and this seems to be a reliable area. I would suspect coil or ignition sensor first to rule them out. ALso check behind headlight to be sure you don't have a wire rubbing on metal and it's eaten through insulation and grounding out(that was a big thing on the older Bonnie's).
Del

 

[Social D 13]

Thanks Del
i appreciate your feedback man...
Pugs are good, Micro filter checked and ok, pulled the Petcock to make sure there wasnt anything in the screen- ok
I need to look @ the coils more-
As for the coils, I am not familar w/ the triumph ones.
We have 2 coils right?
the ones thats on the bottom right by our foot brake and the other is under the tank that goes to our spark plugs?
A multimeter is all i need to make sure they work or is there another way to determin thier usefulness?
The bike flies 2nd gear and up...its just from take off Im having some serious issues.
Carbs are synched and idle is +/- 1000 rpms.
to watch the slides work, id have to take off the air box and i think at this time, its a little more work than i was expecting to do- Maybe i can look @ the electronics before i rip out the box and if i rip out the box, might as well put this K&N air filter pods..
I do have some issues @ idle also w a jumpy needle.
Oddly, when i did a carb synch, the levels were the same, but every now and then, one side would jump up and theyd level out eventually....i thought it was an air leak, but i never tracked it down....
Im a little anxious that my Mixture screws are out 3.75...which in my experience are way too much, especially having 42 pilots and 132.5 mains...im hoping im not masking another issue...

 

[BlueJ]

What mufflers do you have? Sounds like you might be a bit on the rich side, actually. But the jumpy tach at idle is pretty normal for these bikes - they're just not hot off the blocks with the stock power and gearing.

 

[Social D 13]

What mufflers do you have? Sounds like you might be a bit on the rich side, actually. But the jumpy tach at idle is pretty normal for these bikes - they're just not hot off the blocks with the stock power and gearing.

Emgo Reverse Cones are my exhaust.
Things were running fine until the oil change....odd...

 

[Delbert]

We have 2 coils YES, and their both under the fuel tank. The other item under the cover by the foot brake pedal you're calling a coil, is incorrect. It's the "Ignition Sensor". What it does is tell the ECU that the motor can fire the coil, which in turn gives spark to plugs. Actually it can fire at any time the timing pin crosses the firing coil in the sensor. When these go out you'll have troubles(sometimes) with starting, running when warmed up, running at idle/mid/upper RPM's or combination of any, or all problems you discribed for one day OR will run great for a month then will act up at any given time in between. If it's the coil, it will generly act up when warm/hot, BUT be good when cold. Being electronic they'll go out when they want too. It's not milage or age related. On your '04 it should be Triumph #T1290043 @ around $75 and with engine cover gasket #T1260968 @ around $5.50. I've replaced 2 in my '02 in 12K miles. The air gap for sensor if replaced is .8mm which works to around 30 thousandths. This is of course possibly not what is causing your problems and are easier to check out than R & R your carbs to rebuild. Their just something that I KNOW can be bad and causing your problems and for you to check out. I know some owners have had bad ECU's but they were rare. I've only heard of 2 since the Bonnie's came out in '01 and if you replace the unit--it's around $700 from Triumph. ProCom has a replacement unit for less that I know some people have good results with, so I hope this is not your problem.
Del

 

[Delbert]

Something else SocialD, reading your post again. You have your mixture screws out 3.75 turns. I feel that this is too much for your altitude and what your jetting is. You are probably running rich on the idle circuit. 42 on idle jet is good(that's what I have and I'm at 600 altitude here in Missouri) and my mixture screws(both different settings) BUT not out more than 3 turns. These carbs ARE NOT balanced carbs and you may have different screw turns to get running properly. I idle my bike at 1500 RPM's and adjust one screw to reach the highest RPM, then back idle control knob back down to 1500 RPM and do the other carb. Have fan on motor to keep cool. I would also back that 132.5 main jet back down to no more than 130. These year of bikes come with what I believe is 120's(mine is at 125).

 

[Social D 13]

thanks man....I will keep working on dialing in my jets...
as a confirmation- is this what my coil looks like???
http://cgi.ebay.com/ebaymotors/TRIU...1829085QQptZMotorcyclesQ5fPartsQ5fAccessories

 

[Social D 13]

You are probably running rich on the idle circuit. 42 on idle jet is good(that's what I have and I'm at 600 altitude here in Missouri) and my mixture screws(both different settings) BUT not out more than 3 turns. These carbs ARE NOT balanced carbs and you may have different screw turns to get running properly. I idle my bike at 1500 RPM's and adjust one screw to reach the highest RPM, then back idle control knob back down to 1500 RPM and do the other carb. Have fan on motor to keep cool. I would also back that 132.5 main jet back down to no more than 130. These year of bikes come with what I believe is 120's(mine is at 125).

hey Del
can you share more info on this?
On my Honda and Yamaha- the settings had to be the same and then you synch your carbs...
this is new to me...you can really have different settings on the dfifferent carbs?
Also, can you walk me through what i will be looking for as i adjust the Mixture screw one at a time? What i use to look for in my original theory was steady idle and ridability, then makinh sure my carbs were @ equaly levels when carb synching> what do you mean by idleing your bike @ 1500 rpms and then adjusting the mixture screw one at a time??thanks for your insight...

 

[Delbert]

The carbs are "NOT BALANCED". By this I mean that the carbs are cast into their shape then machined to a tolerance spec and they could be 50 CFM off between the two. This way you(the customer) gets a reliable bike, but it needs some fine tuning to retrieve all the true power out of it. Some people just hop on and ride and to them everything is GREAT for the life of the machine, while others like to tweak and fine tune to make a good bike into a great bike. This is what all the changing out of jets,air mixture screw adjusting,new shocks/rebuilt frontends,handle bars,adding tachs,etc.
The adjusting of carbs is simple(I didn't ask if you had a Tachometer), but this would help in fine tuning. If no tach then you need to do it by ear OR try to find a hand held tach that they use for Radio Control hobbies, but they're not necessary.
What you do is start up bike and let warm up(choke off) and have fan(s) blowing onto engine and oil cooler to help with cooling(very important) as you DON'T want to run an air/oiled motor too long without any air circulating around it or it will destroy itself. OK, engine is now settled into a nice idle of around 1000RPM. Take the idle control knob and turn up to 1500RPM and use this as tuning basis. Slowly turn (out and in) one carburator(doesn't make difference which you start with) until you reach the HIGEST RPM for that carburator. If this has taken more than 5 minutes--STOP motor and let cool down a bit while fan is still blowing on it(about 15 minutes is ok) restart bike, then make sure you have RPM back up to 1500RPM and do the other carburator the same way as first carb. When you have attained your goal, just turn the idle knob back down to 900 to 1100 RPM's and you've tuned both carbs with proper air mixtures. Don't worry that one carb has 2.75 turns and other carb only has 2.25 turns. Your goal is to balance carbs with air mixture. It isn't the same as syncing carbs which is with the little bolt between the carbs that the throttle cables attach to and have both slides open/close at same time. As I said before these carbs aren't balanced to each other from factory(exact to within 1% of each other for CFM's, Jets, Diaphram springs, Tolerances. This requires hand selection and many tests on a CFM machine and you've taken a $200 carb and made it a $1000 carburator, so this is not cost effective. As to Honda and Yamaha and how to tune their carbs, a real mechanic would do the same as what I described above---However some newer style carbs don't have air mixture screws available to be adjusted. They're sealed at the factory, or they have fuel injection and only thing to do is sync the carbs between each other so slides or butterflys open/close at same time. Most people don't want the blue pipes, so they wind up rejetting rich, while I don't mind blue pipes, I have a bike that runs good without wasting fuel and no hesitation(no needle shims). You should be fine with a 42 jet on idle/mid range. You may need a shim washer on the carb needles however, but do the air mixture screw thing first. I would drop the main jet down to no more than 130 though. Ride and give thoughts, readjust, ride again, readjust, keep doing this until you achieve your goals about how you want your bike to run. It can be a long process. I hope I answered your question(s).
Del

 

[Social D 13]

The carbs are "NOT BALANCED". By this I mean that the carbs are cast into their shape then machined to a tolerance spec and they could be 50 CFM off between the two. This way you(the customer) gets a reliable bike, but it needs some fine tuning to retrieve all the true power out of it. Some people just hop on and ride and to them everything is GREAT for the life of the machine, while others like to tweak and fine tune to make a good bike into a great bike. This is what all the changing out of jets,air mixture screw adjusting,new shocks/rebuilt frontends,handle bars,adding tachs,etc.
The adjusting of carbs is simple(I didn't ask if you had a Tachometer), but this would help in fine tuning. If no tach then you need to do it by ear OR try to find a hand held tach that they use for Radio Control hobbies, but they're not necessary.
What you do is start up bike and let warm up(choke off) and have fan(s) blowing onto engine and oil cooler to help with cooling(very important) as you DON'T want to run an air/oiled motor too long without any air circulating around it or it will destroy itself. OK, engine is now settled into a nice idle of around 1000RPM. Take the idle control knob and turn up to 1500RPM and use this as tuning basis. Slowly turn (out and in) one carburator(doesn't make difference which you start with) until you reach the HIGEST RPM for that carburator. If this has taken more than 5 minutes--STOP motor and let cool down a bit while fan is still blowing on it(about 15 minutes is ok) restart bike, then make sure you have RPM back up to 1500RPM and do the other carburator the same way as first carb. When you have attained your goal, just turn the idle knob back down to 900 to 1100 RPM's and you've tuned both carbs with proper air mixtures. Don't worry that one carb has 2.75 turns and other carb only has 2.25 turns. Your goal is to balance carbs with air mixture. It isn't the same as syncing carbs which is with the little bolt between the carbs that the throttle cables attach to and have both slides open/close at same time. As I said before these carbs aren't balanced to each other from factory(exact to within 1% of each other for CFM's, Jets, Diaphram springs, Tolerances. This requires hand selection and many tests on a CFM machine and you've taken a $200 carb and made it a $1000 carburator, so this is not cost effective. As to Honda and Yamaha and how to tune their carbs, a real mechanic would do the same as what I described above---However some newer style carbs don't have air mixture screws available to be adjusted. They're sealed at the factory, or they have fuel injection and only thing to do is sync the carbs between each other so slides or butterflys open/close at same time. Most people don't want the blue pipes, so they wind up rejetting rich, while I don't mind blue pipes, I have a bike that runs good without wasting fuel and no hesitation(no needle shims). You should be fine with a 42 jet on idle/mid range. You may need a shim washer on the carb needles however, but do the air mixture screw thing first. I would drop the main jet down to no more than 130 though. Ride and give thoughts, readjust, ride again, readjust, keep doing this until you achieve your goals about how you want your bike to run. It can be a long process. I hope I answered your question(s).
Del

thanks Del
So another words- RPM @ 1500, and i turn the Mixture screws on the carb ( one at a time) until the rpms max out right? I assuming that at a certain point, turning the screws wont increase the RPMs correct? Does it matter what the other carb ( thats not being adjusted yet) should be (mixture screwwise) at or does that not matter?
Thats interesting and ive never encountered that method before...
In your experience, when you do one carb mixture screw at a time @ 1500 RPMs, how high does your RPMs jump up as you're trying to find that maximum level?

 

[BlueJ]

Start on the left. Turn it in a bit - did rpms go up? If so, turn in some more. Repeat until rpms don't go up any more. If they went down at first, then turn the other way. If they go down in both directions, you're done on the left side. Go to the right side and repeat. Confirm that when you go back to the left turning in either direction causes a drop in rpm. You MIGHT need to do two iterations but it's unlikely.

Depending on how badly out of whack your current setup is, you might be looking at 1-200 rpm is all.

Then turn idle back down and balance with vacuum setup and the center screw.

 

[Social D 13]

hey guys,
just an update.
purchased a multimeter and checked the primary resistance on my HT coils.
Readings were showing 1.3-1.8....
hayenes says it should be 6 ohms...
this bad????

what do bad HT coils cause?? maybe my issues off the line?? maybe causing 1 cylynder to cut out??? what are the symptoms??

secondary test w/ the spark plug caps didnt show anything....i didnt have a reading for some reason-- haynes says it should be @ 15k OMS and my resistance readings never move from 1....it was odd...maybe im using a multimeter wrong....

spark plug wires- end to end, resistance was good @ 5 and 5.2 ohms...so
a) my multimeter works
b) its not the wires from the plugs to the coils...

any thoughts and #1 and #2 above????

 

[Carnation]

Have the caps been changed ever? Could be the original ones have resistors incorporated for interference suppression and the ones on your bike do not.

 

[Social D 13]

Have the caps been changed ever? Could be the original ones have resistors incorporated for interference suppression and the ones on your bike do not.

No they have not, but when I pulled them from the spark plugs and the coil, They measured the appropriate resistance @ 5000 ohms....its odd, the service manual doesn't have the HT coil Ohm range for the primary test.....only the haynes does...should I trust the Haynes?? And does my lower reading mean that my ht coils are bad?
Seems triumphs recommendation is to get some that work, install and see if the prob goes away.
I don't want to drop $80 if I don't have to.....

 

[Social D 13]

Hey guys
Thanks for all of your support.
After tearin into the thrux-
A) imma better mechanic
B) I still love my thruxton
C) I realized, after a swap, that the prob was from my HT coil.
Put a slightly used one and steady as she goes!
Former mixture settings were 3.5 and 3.75, but based on your feedback, got em down to 1.75 and 2, w 1 shim on both needles. I had it down to 1.5, but I started hearing popping on deceleration, so I bumped them up a tad.
Thanks to you all, especially Delbert who helped out and provided encouragment. Gonna order a Nology ht coil this week and we should be golden!