BritBike Forum logo
BritBike Sponsor BritBike Sponsor BritBike Sponsor
BritBike Sponsor

BritBike Sponsor

BritBike Sponsor
BritBike Sponsor BritBike Sponsor BritBike Sponsor
  JWood Auction  
Home | Sponsors, Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons, "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Photo posting tutorial

Member Spotlight
JON BRYANT
JON BRYANT
OLYMPIA WASH.
Posts: 26
Joined: June 2007
Show All Member Profiles 
Shout Box
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Random Gallery photo
Who's Online Now
204 registered members (57nortonmodel77), 1,565 guests, and 558 spiders.
Key: Admin, Global Mod, Mod
Newest Members
Regi, Doug Baril, revans, Gilly, XTINCT
9961 Registered Users
Top Posters(30 Days)
btour 185
koan58 101
Stuart 86
NickL 69
Popular Topics(Views)
440,153 mail-order LSR
Forum Statistics
Forums33
Topics65,305
Posts632,363
Members9,961
Most Online3,995
Feb 13th, 2017
Like BritBike.com on Facebook

Previous Thread
Next Thread
Print Thread
Rate This Thread
#94503 - 06/22/06 1:15 pm Engine cutting out when opening throttle from idle  
Joined: Feb 2006
Posts: 1,095
Matthew in TO Offline
BritBike Forum member
Matthew in TO  Offline
BritBike Forum member

Joined: Feb 2006
Posts: 1,095
Toronto, Ontario, Canada
Recently I've been having a problem with my 1970 T100S (1969 T100S motor). When I come to a stop after running for a few minutes in traffic, and either sit in first or neutral, when I rev the throttle (in neutral or in first to pull away from the stop) a few times the engine will make a single "splut" sound, and then immediately die. Almost always it will restart on a single kick. Once running at a constant speed, there is no issue, but in traffic I'm worried that at every stop she might splut and die. This started about two weeks ago, and has happened about 4-6 times now. It happens only when I open the throttle from idle; otherwise she'll idle without trouble.

I don't know if it's related, but I generally do not rev the bike high when pulling away from stops, and prefer to change gears usually before 4,000 rpm, and run at 35-40 mph still in 4th gear when cruising around town. A fellow brit biker in town said I'm fouling my plugs, since I should be rev'ing to over 5,000 rpm between shifts, and in 35-40 mph traffic should cruise in 3rd gear at high revs. I don't have a tool to remove the plugs yet (need the correct socket set piece). Could fouled plugs cause this intermittent problem of engine cut-out when opening throttle from idle?


1970 Triumph T100S (1969 T100S motor)
Support Your #1 BritBike Forum!
Membership Type! Free
Member
Premium
Member
Premium Life
Member
Vendor
Member
Site
Sponsor
Recognition No Premium Member Premium Life member (5 years) Vendor Member Site Sponsor Membership
Post commercial threads No No No Yes Yes
Custom title No Yes Yes Yes Yes
Upload avatar & photos No Yes Yes Yes Yes
Link avatar & photos Yes Yes Yes Yes Yes
Private Message Storage: 10 100 100 100 100
Length of signatures 255 600 600 600 600
Removes this very advert island between post 1&2 No Yes Yes Yes Yes
Price Free $12.90/year $105.00 No End
$55.00/5 years
$210.00/year
($17.50/month)
Email
Click on button >>
  Premium Member Premium Life member Vendor Member Site Sponsor Membership
#94504 - 06/22/06 1:25 pm Re: Engine cutting out when opening throttle from idle  
Joined: Nov 2005
Posts: 7,224
JubeePrince Online content
Life member
JubeePrince  Online Content

Life member

Joined: Nov 2005
Posts: 7,224
Back on the mainland!
Matthew -

Fouled plugs could certainly be one cause of this problem, however, fouled plugs seem to me to be a symptom of some other problem, perhaps running too rich......my bike had this problem when i was in the process of dialing everything in and for me it was an issue of air-mixture adjustment.

FWIW - get yourself a plug wrench man!! Those plugs can tell you alot about the running condition of your bike....you could pick up one real cheap in any auto parts store up there in the Great White North.... smile

HTH,

Steve Prince


'77 T140J
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
#94505 - 06/22/06 1:25 pm Re: Engine cutting out when opening throttle from idle  
Joined: Dec 2004
Posts: 8,896
kommando Online content
kommando  Online Content


Joined: Dec 2004
Posts: 8,896
Scotland
Sounds like the carb slide is wearing loose and letting too much air past, is your idle speed erratic, if so you will need to get you carb body bored out to to take a re-sleeved slide. The new amals have too may quality issues plus have the old wear quicly setup on the body and slide too, re-sleeved has the longer lasting setup.

#94506 - 06/22/06 2:29 pm Re: Engine cutting out when opening throttle from idle  
Joined: Aug 2005
Posts: 1,145
Vox Teardrop Offline
BritBike Forum member
Vox Teardrop  Offline
BritBike Forum member

Joined: Aug 2005
Posts: 1,145
Indy
I had these people refurb/rebore my carbs.

http://www.tritonmachining.com/


95' Triumph Speed Triple
72' Triumph T120
64' BSA Lightning Rocket
#94507 - 06/22/06 5:04 pm Re: Engine cutting out when opening throttle from idle  
Joined: Feb 2006
Posts: 1,095
Matthew in TO Offline
BritBike Forum member
Matthew in TO  Offline
BritBike Forum member

Joined: Feb 2006
Posts: 1,095
Toronto, Ontario, Canada
Quote:
Originally posted by kommando:
Sounds like the carb slide is wearing loose and letting too much air past, is your idle speed erratic, if so you will need to get you carb body bored out to to take a re-sleeved slide. The new amals have too may quality issues plus have the old wear quicly setup on the body and slide too, re-sleeved has the longer lasting setup.
The bike's idle speed is not erratic, I'd say, with a regular and small 200-500 rpm up/down on the tach at around 1,500 rpm. I've always thought it was just the vibration of the bike. The exhaust certainly sounds regular and in constant time at idle.

Does the daily need to push the carb tiggle button a 6-8 times per cold start-up wear out the parts that would affect this? FYI, my does does not have a choke, as it's been plugged over and cable's removed.

I'll purchase the necessary socket and pull the plugs for inspection tonight.


1970 Triumph T100S (1969 T100S motor)
#94508 - 06/22/06 5:34 pm Re: Engine cutting out when opening throttle from idle  
Joined: Dec 2004
Posts: 8,896
kommando Online content
kommando  Online Content


Joined: Dec 2004
Posts: 8,896
Scotland
That idle looks high and erratic to me, 1100 +/- 50 would be more like it. If you blip the throttle and let it idle does it settle at different revs each time, if it does its new slide time or re-sleeve.

#94509 - 06/22/06 5:36 pm Re: Engine cutting out when opening throttle from idle  
Joined: Aug 2005
Posts: 1,145
Vox Teardrop Offline
BritBike Forum member
Vox Teardrop  Offline
BritBike Forum member

Joined: Aug 2005
Posts: 1,145
Indy
Carb tickler can't wear anything out.


95' Triumph Speed Triple
72' Triumph T120
64' BSA Lightning Rocket
#94510 - 06/22/06 6:14 pm Re: Engine cutting out when opening throttle from idle  
Joined: Apr 2006
Posts: 176
Colin_In_Ottawa Offline
BritBike Forum member
Colin_In_Ottawa  Offline
BritBike Forum member

Joined: Apr 2006
Posts: 176
Ottawa Canada
If this only happens hot rather than cold it would indicate a rich rather than lean-out condition (which would be wose when cold when you NEED a rich mixture)
So that would eliminate things like exhaust and intake leaks. Tried it with the air filter off?

See if slowly raising the revs before taking off is better than quickly twisting the throttle and taking off. Sure sound slike its just getting a bad "choking" condition when taking off. I dont know squat yet about Amals to speculate on it to be the cause but engines only need 4 things to run and it sounds like yours is either getting too much fuel or not enough air when you twist that throttle.


*******************************
70 Bonnie
70 T100s Bobber
07 Bonnie
10 Tbird
#94511 - 06/22/06 7:03 pm Re: Engine cutting out when opening throttle from idle  
Joined: Feb 2006
Posts: 1,095
Matthew in TO Offline
BritBike Forum member
Matthew in TO  Offline
BritBike Forum member

Joined: Feb 2006
Posts: 1,095
Toronto, Ontario, Canada
Speaking of air filter, the bike did cut out once in the driveway, and I noticed a puff of fuel or dust or something "cloudy" from the air filter.


1970 Triumph T100S (1969 T100S motor)
#94512 - 06/22/06 8:57 pm Re: Engine cutting out when opening throttle from idle  
Joined: Feb 2006
Posts: 120
birdoprey Offline
BritBike Forum member
birdoprey  Offline
BritBike Forum member

Joined: Feb 2006
Posts: 120
Hi Matthew,

I can’t remember if the T00S has one or two carbs but I’m pretty sure it has concentrics. These things are notorious for doing exactly what you are describing.

Yes, it may be aggravated by worn slides, yes, other things can wear in there as well. But, the most common cause of this is the pilot jet being obstructed. Some of them can be cleaned with a fine wire (I’ve heard of using the bristle from a wire brush) but sometimes it really takes some doing to clean them out. There is also some difference in the location of the pilot jet with some of those carbs.

Yes, you can soak them in carb cleaner and you can blow them out with an air compressor, but still sometimes it just takes something mechanical to poke the crud from the passage/jet.

If yours is a two carb model, you can do some swapping of parts like the slides to see if it changes things. I can also give you a blow by blow to sync them the best you can with out expensive equipment. Let me know.

I have some AMAL tech sheets that I can send you if that will help.

When it “coughs” like that it’s probably spitting back through the carb and blowing fuel out the air cleaner. Once you solve the “cough” you probably won’t see that “cloudy” stuff coming from the air cleaner

Art.

#94513 - 06/22/06 9:17 pm Re: Engine cutting out when opening throttle from idle  
Joined: Mar 2005
Posts: 9,971
John Healy Online content
John Healy  Online Content



Joined: Mar 2005
Posts: 9,971
Boston, Massachusetts
quote Art:
Some of them can be cleaned with a fine wire (I’ve heard of using the bristle from a wire brush) but sometimes it really takes some doing to clean them out
--------------------------------------------
Just remember that we are cleaning out a jet, not a hole. Not only should the jet be clear, but it needs to be the right size. A small wire might open a hole, but the right size wire will make it a jet again.
2c


#94514 - 06/22/06 11:30 pm Re: Engine cutting out when opening throttle from idle  
Joined: Feb 2006
Posts: 635
Ginge Offline
BritBike Forum member
Ginge  Offline
BritBike Forum member

Joined: Feb 2006
Posts: 635
Qld, Aust and Otago,NZ
Matthew,

I'm thinking it's in the pilot and idle circuits. It might just be a bit off tune when hot. Go for a ride and get it warm, then come back and annoy the neighbours for half an hour and play with the pilot air screw and idle screw. Do this before poking things into the pilot jets. You only need a flat blade screwdriver.

Note the current setting on the pilot air screw, and count the turns to screw it in gently 'til it stops. If you get in trouble later on return to this setting. Now, wind the pilot air screw out 1 and half to 2 turns.

Start the bike and raise the idle a bit so it runs a little bit fast, then screw the pilot air screw in or out to get the idle running even faster. Turn about 1/4 to 1/8 each time. Give the bike 10-15 seconds to catch up with the adjustment. You are aiming to get it to run with an even, steady beat. No Harley lumpy lump noises, this is a Triumph.

Maybe blip the throttle a bit to make sure it comes back down to the same idle position each time. This is a great way to meet the neighbours. When it sounds nice and even, lower the idle a bit and fine tune with pilot air screw (now moving it 1/8 to 1/16 turns each time). You may find you got it pretty close the first time through the process.

When you get where you are happy, with a steady beat , and the idle about right for a hot engine, go for another ride and see how it responds. Stay out of the traffic until you are happy that it is going to behave. Old bikes behaving badly in traffic are not fun.

If this don't cure it you're going to have to look elsewhere, but at least you know what it isn't, and no harm done.

You might find that after this the bike is a bit harder to start when it's cold. Maybe you've richened or leaned it slightly from where it was. You'll have to adjust your starting drill accordingly (more or less tickling). Better to be a bit harder to start in the carpark, than stalling at the lights in front of a line of cars.

And yeah, get a plug spanner. Get a short one or a folding one one that you can put in the pocket of you're bike jacket or tool roll, so you always have it when you ride. Carry a spare plug too. Fundamental Triumph stuff that. Pulling plugs on the side of the road will tell you a lot (whether you have spark, whether you have fuel, whether you can fix it or need to get a ride home etc.).

And don't be frightened to wring the bike's neck. The 500's respond well to that. You may find some power you didn't know you had.


Ginge
#94515 - 06/23/06 2:37 am Re: Engine cutting out when opening throttle from idle  
Joined: Feb 2006
Posts: 120
birdoprey Offline
BritBike Forum member
birdoprey  Offline
BritBike Forum member

Joined: Feb 2006
Posts: 120
<just remember, we are cleaning out a jet, not a hole. Not only should the jet be clear, it needs to be the right size>

Anyone know what the correct size of this jet is?

Art.

#94516 - 06/23/06 6:29 am Re: Engine cutting out when opening throttle from idle  
Joined: Oct 2004
Posts: 4,429
Tiger Offline
BritBike Forum member
Tiger  Offline
BritBike Forum member

Joined: Oct 2004
Posts: 4,429
Melbourne Australia
Quite possibly .016" or the size of a # 72 drill bit ?
There is a thread here somewhere where that was mentioned by one of the knowledgable ones, not sure if that size is common with the smaller concentrics and the 930.
If I recall correctly it was a problem just such as yours [with the 500 twins] that led to AMAL going away from from a jet in the roof of the float chamber in favour of the bush, which is further downstream.
I used to use a strand from a broken cable to clean the pilot bush until I became civilised and bought a # 72 bit and epoxied it to a piece of clean "squirt tube" from an aerosol can [another good idea from here].
The cable strand never seemed to cause any problems.


1969 TR6R
7.62 x 51 is not a maths puzzle.
#94517 - 06/23/06 11:03 am Re: Engine cutting out when opening throttle from idle  
Joined: Nov 2005
Posts: 7,224
JubeePrince Online content
Life member
JubeePrince  Online Content

Life member

Joined: Nov 2005
Posts: 7,224
Back on the mainland!
Quote:
Originally posted by Tiger:
Quite possibly .016" or the size of a # 72 drill bit ?
FWIW - .016" = # 78 drill bit......

Cheers,

Steve Prince


'77 T140J
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
#94518 - 06/23/06 12:21 pm Re: Engine cutting out when opening throttle from idle  
Joined: Feb 2006
Posts: 120
birdoprey Offline
BritBike Forum member
birdoprey  Offline
BritBike Forum member

Joined: Feb 2006
Posts: 120
Thanks Steve and Tiger,

Good information, I'll note that in my manual for next time.

Art.

#94519 - 06/23/06 3:44 pm Re: Engine cutting out when opening throttle from idle  
Joined: Apr 2004
Posts: 538
Matthew Manton Offline
BritBike Forum member
Matthew Manton  Offline
BritBike Forum member

Joined: Apr 2004
Posts: 538
Toronto
Hi Matthew,

I have exactly the same problem with my 1970 T100S, let us know what you did to get it sorted.

Cheers
Matthew in Toronto


Matthew
1970 T100S
#94520 - 06/23/06 6:54 pm Re: Engine cutting out when opening throttle from idle  
Joined: Jun 2006
Posts: 319
KrispyKris Offline
BritBike Forum member
KrispyKris  Offline
BritBike Forum member

Joined: Jun 2006
Posts: 319
Germany
Quote:
Originally posted by Matthew in Fredericton:
Quote:
Originally posted by kommando:
Sounds like the carb slide is wearing loose and letting too much air past, is your idle speed erratic, if so you will need to get you carb body bored out to to take a re-sleeved slide.
The bike's idle speed is not erratic, I'd say, with a regular and small 200-500 rpm up/down on the tach at around 1,500 rpm. I've always thought it was just the vibration of the bike. The exhaust certainly sounds regular and in constant time at idle.
I would say it is most probably the slides. When riding around, it is possible to hear them rattling...it is not valve noise...I would say that a 200 rpm variation is pretty severe. In addition, idle should be around 750. New brass slides are a cheaper alternative. The slides seem to go away faster then the bores. Sleeving is pretty expensive...more later. Have to run..JK


BGL, Deutschland.
'67 Bonnie w/140V, '76 T160, '52 Vincent Rapide.
"Is that 'normal' mechanical noise, or the sound of imminent destruction...?"
#94521 - 06/24/06 7:54 am Re: Engine cutting out when opening throttle from idle  
Joined: Oct 2003
Posts: 3,524
dave jones Offline
BritBike Forum member
dave jones  Offline
BritBike Forum member

Joined: Oct 2003
Posts: 3,524
Emsworth, sunny south of Engla...
I'm with Ginge here. Just try adjusting the idle circuit. Timing could be advanced so you should check this first. If you open the throttle and it spits back through the carb and dies you have either advanced timing or a too weak idle mixture or possibly a too weak slide. Good to clean the idle jet if possible, not with wire but some other stiff object like a thick paint brush bristle.

I read in a book by Steve Wilson that the late 500s were prone to stalling.

My 650 has had all these symptoms and they can be tuned out without changing parts. I also just take the occasional stall as normal as I do a slightly erratic idle. Hot cams in the Triumph twin make therm a bit lumpy. If my Moto Guzzi idled like my Triumph I would be worried!

#94522 - 06/28/06 3:56 am Re: Engine cutting out when opening throttle from idle  
Joined: Feb 2006
Posts: 635
Ginge Offline
BritBike Forum member
Ginge  Offline
BritBike Forum member

Joined: Feb 2006
Posts: 635
Qld, Aust and Otago,NZ
Matthew you've got a high idle, and an erratic idle. Makes me think that it is not idling on the pilot circuit at all, but on the slide cutaway.

This will happen if your throttle cable is not letting the slide drop right down (check the adjuster at the handlebar or look for kinked or crushed cable), or if the idle screw is in too far (screw it out 'til it dies, then start from scratch on the pilot air screw at 1 and 1/2 turns out)

I'm thinking that when you crack the throttle just a little bit, you lift the slide and get a bucket load of air and not a lot of fuel to match it (because the engine isn't spinning fast enough to lift gas up the needle.

Failing that you should ride to see Matthew T100S, meet half way, have a beer and ***** about your bikes. Typical biker stuff.


Ginge

Moderated by  John Healy 


Home | Sponsors | Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons | "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.505s Queries: 14 (0.014s) Memory: 0.9513 MB (Peak: 1.2406 MB) Zlib disabled. Server Time: 2017-11-25 00:00:30 UTC