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1970 T100S – It Breathes Again #409472
12/19/11 9:31 pm
12/19/11 9:31 pm
Joined: Apr 2004
Posts: 538
Toronto
Matthew Manton Offline OP
BritBike Forum member
Matthew Manton  Offline OP
BritBike Forum member
Joined: Apr 2004
Posts: 538
Toronto
Hi Guys,

Just recently got my 1970 T100 back on the road after the conrod broke in October 2010. I have a little problem, the bike is hesitating between Ό and ½ throttle and I wanted to pick your brains before I stash it away for the winter, it’s starting to get a little chilly in Toronto now.

A couple of pictures of Armageddon 2010:





Really it should be registered now as a 2012 model after all the new stuff in the bike.
I had to get new cases, new barrel (re-bored +0.040”), pistons, new exhaust camshaft, the old one was little bent.
Started it up a few weeks ago and it was ruining really rough, checked out the battery and it was not up to the job. Bought a new battery and all was looking good. I have a Boyer ignition installed, amazing what a couple of volts can do? So with the new battery I was pleasantly surprised how well it was running after the rebuild.

Check out the video here:


I have done about 150 miles on the bike so far. I have not been babying it but not thrashing the living daylights out of it. Re torqued the head and base nuts twice, changed the oil this afternoon.

Trouble is there is hesitation when accelerating. I put some masking tape on the throttle and marked it up in Ό segments so I could see ½, Ό throttle etc. The bike ticks over great, but there is hesitation between Ό and Ό throttle. Once you go pass1/2 throttle everything is good, whips up the road like a gazelle, no hesitation what so ever.

I have an AMAL Concentric single carb setup, with no choke. I bought the carb new about three years ago and before the blow up everything was running fine.

The specs for my carb are:
Carb Size: 26 MM
Slide #4
Main Jet 180
Neddle Jet .106
I have the clip installed on the top ring of the needle.
This setup worked great before Armageddon.

What I have done so far:
Last week I dismantled the carb again and ensured the pilot jet was clear using #78 drill. Checked the drill after insertion and no grunge on the flutes of the drill. I checked the float, all looked good 0.080” below the surface.
I have a tank full of new gas.
Checked the timing with a strobe, bang on.
Re-Checked and adjusted the valve clearances.

Any ideas on what I should do next?

Cheers
Matthew Manton

Last edited by Matthew Manton; 12/19/11 9:33 pm.

Matthew
1970 T100S
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Re: 1970 T100S – It Breathes Again [Re: Matthew Manton] #409489
12/19/11 10:42 pm
12/19/11 10:42 pm
Joined: Jun 2007
Posts: 5,700
Maui Hawaii
HawaiianTiger Offline

BritBike Forum member
HawaiianTiger  Offline

BritBike Forum member
Joined: Jun 2007
Posts: 5,700
Maui Hawaii
Have you played with the needle position? You're already as lean as you can get with a #4 slide with the clip at the top so there's lots of adjustment left.
Bill


Bikes
1974 Commando
1985 Honda Nighthawk 650
1957 Thunderbird/T110 "Flying Tiger"
Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
Re: 1970 T100S – It Breathes Again [Re: HawaiianTiger] #409496
12/19/11 10:58 pm
12/19/11 10:58 pm
Joined: Apr 2004
Posts: 538
Toronto
Matthew Manton Offline OP
BritBike Forum member
Matthew Manton  Offline OP
BritBike Forum member
Joined: Apr 2004
Posts: 538
Toronto
Hi Tiger,

Did not touch the neddle position as it was running fine before the blow up.

But a good idea to move the clip, I should check it out on the middle ring.

Cheers
Matthew


Matthew
1970 T100S
Re: 1970 T100S – It Breathes Again [Re: Matthew Manton] #409519
12/20/11 3:03 am
12/20/11 3:03 am
Joined: Feb 2008
Posts: 4,252
New Jersey USA
Tridentman Online content

BritBike Forum member
Tridentman  Online Content

BritBike Forum member
Joined: Feb 2008
Posts: 4,252
New Jersey USA
Hi Matt--any theories on what caused the original blow up?

Re: 1970 T100S – It Breathes Again [Re: Tridentman] #409524
12/20/11 3:49 am
12/20/11 3:49 am
Joined: Apr 2004
Posts: 538
Toronto
Matthew Manton Offline OP
BritBike Forum member
Matthew Manton  Offline OP
BritBike Forum member
Joined: Apr 2004
Posts: 538
Toronto
No clue to why the conrod went south.

Matthew


Matthew
1970 T100S
Re: 1970 T100S – It Breathes Again [Re: Matthew Manton] #409543
12/20/11 11:14 am
12/20/11 11:14 am
Joined: Jul 2010
Posts: 116
Bath, UK
S
steverat Offline
BritBike Forum member
steverat  Offline
BritBike Forum member
S
Joined: Jul 2010
Posts: 116
Bath, UK
Spectacular photos, that must have made quite a bang. Were you going at speed when it happened?


1924 SS80
1953 18S
1955 18CS
2013 Striple
Re: 1970 T100S – It Breathes Again [Re: Matthew Manton] #409546
12/20/11 12:09 pm
12/20/11 12:09 pm
Joined: Nov 2005
Posts: 737
Reading UK
twinspin Offline
BritBike Forum member
twinspin  Offline
BritBike Forum member
Joined: Nov 2005
Posts: 737
Reading UK
I would also say that the needle up a notch is worth a try. Failing that screw in the slow running screw in a little on the carb to richen it a little. Ignore the effect this initially has on tickover before you do anything else to see if it gets rid of the hesitation.


1971 T100R
1970 T120
Re: 1970 T100S – It Breathes Again [Re: Matthew Manton] #409550
12/20/11 12:34 pm
12/20/11 12:34 pm
Joined: Apr 2004
Posts: 538
Toronto
Matthew Manton Offline OP
BritBike Forum member
Matthew Manton  Offline OP
BritBike Forum member
Joined: Apr 2004
Posts: 538
Toronto
Steverat,

I was doing about 50 MPH when all hell broke loose. Bloody great bang, back wheel locked up and I very quickly pulled in the clutch.
Luckily for me my wife was behind me on her bike and not a cement truck.

Cheers
Matthew


Matthew
1970 T100S
Re: 1970 T100S – It Breathes Again [Re: Matthew Manton] #409605
12/20/11 9:18 pm
12/20/11 9:18 pm
Joined: Apr 2004
Posts: 538
Toronto
Matthew Manton Offline OP
BritBike Forum member
Matthew Manton  Offline OP
BritBike Forum member
Joined: Apr 2004
Posts: 538
Toronto
Hi Guys,

I moved the needle to the centre notch this afternoon and then went for a ride around the neighbourhood. Much better performance now no hesitation.

A touch on the chilly side here in Toronto at -2 C (27 F), so I think it is time to stash the bike away for the winter and carry on with some fine tuning in the Spring. Man that sounds a long way off.

Thanks for all your suggestions guys.

Cheers
Matthew


Matthew
1970 T100S
Re: 1970 T100S – It Breathes Again [Re: Matthew Manton] #409612
12/20/11 10:12 pm
12/20/11 10:12 pm
Joined: Sep 2007
Posts: 1,593
Shingle Springs, California
Roadwarrior Offline

BritBike Forum member
Roadwarrior  Offline

BritBike Forum member
Joined: Sep 2007
Posts: 1,593
Shingle Springs, California
You might get a little more out if it if you replace the main jet with a .190 as called for in the manual.


Bob


73 Triumph T140 Main Ride
70 Bonnie
67 BSA West Coast Hornet

56 Chevy

Who are the brain police?



Re: 1970 T100S – It Breathes Again [Re: Matthew Manton] #409613
12/20/11 10:13 pm
12/20/11 10:13 pm
Joined: Aug 2001
Posts: 7,295
scotland
triton thrasher Offline
BritBike Forum member
triton thrasher  Offline
BritBike Forum member
Joined: Aug 2001
Posts: 7,295
scotland
Always always always get it too rich then weaken the mixture until correct. Especially important with main jet and needle position.

It's basic procedure.


Amateur Loctite enthusiast.
Re: 1970 T100S – It Breathes Again [Re: Matthew Manton] #409619
12/20/11 10:32 pm
12/20/11 10:32 pm
Joined: Sep 2007
Posts: 1,593
Shingle Springs, California
Roadwarrior Offline

BritBike Forum member
Roadwarrior  Offline

BritBike Forum member
Joined: Sep 2007
Posts: 1,593
Shingle Springs, California
Especially on a new build. I'll run rich on purpose.


Bob


73 Triumph T140 Main Ride
70 Bonnie
67 BSA West Coast Hornet

56 Chevy

Who are the brain police?



Re: 1970 T100S – It Breathes Again [Re: Matthew Manton] #409649
12/21/11 1:28 am
12/21/11 1:28 am
Joined: Sep 2001
Posts: 2,792
Comox BC Canada
G
Gordo in Comox Offline
BritBike Forum member
Gordo in Comox  Offline
BritBike Forum member
G
Joined: Sep 2001
Posts: 2,792
Comox BC Canada
Matthew: Nice to see you are back on the road with the T100. Some folks would have just packed it in with the damage you had. Good work.

Gordo


Without frequent roadside repairs there is no fun in riding!
Re: 1970 T100S – It Breathes Again [Re: Matthew Manton] #409693
12/21/11 12:41 pm
12/21/11 12:41 pm
Joined: Jan 2005
Posts: 1,659
East Bethany New York
Dick Harris Offline
BritBike Forum member
Dick Harris  Offline
BritBike Forum member
Joined: Jan 2005
Posts: 1,659
East Bethany New York
Good to see you didn't give up on the little T-100. I had the same thing happen on a '70 T-120 many years ago.At the time Triumph was having a problem with rod manufacturers but I never heard that was the case with 500 rods. Maybe John will dive in here and give us "the rest of the story" Dick

Re: 1970 T100S – It Breathes Again [Re: Dick Harris] #409872
12/22/11 4:45 pm
12/22/11 4:45 pm
Joined: Apr 2004
Posts: 538
Toronto
Matthew Manton Offline OP
BritBike Forum member
Matthew Manton  Offline OP
BritBike Forum member
Joined: Apr 2004
Posts: 538
Toronto
Ordered the 190 jet from Walridge, thanks for all your help guys.

Will keep you posted.

Cheers
Matthew


Matthew
1970 T100S

Moderated by  John Healy 


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