BritBike Forum logo
BritBike Sponsor BritBike Sponsor BritBike Sponsor
BritBike Sponsor

BritBike Sponsor

BritBike Sponsor
BritBike Sponsor BritBike Sponsor BritBike Sponsor
The Bonneville Shop JRC Engineering dealers
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
Member Spotlight
Slasher
Slasher
Essex, UK
Posts: 35
Joined: August 2006
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
20 registered members (Alan_nc), 173 guests, and 431 spiders.
Key: Admin, Global Mod, Mod
Newest Members
Justintimeclark, Tim Pedder, blayde54, Davenz13, Sean65
10479 Registered Users
Top Posters(30 Days)
NickL 97
franko 81
Triless 72
Popular Topics(Views)
750,824 mail-order LSR
Forum Statistics
Forums34
Topics68,866
Posts670,826
Members10,479
Most Online3,995
Feb 13th, 2017
Like BritBike.com on Facebook

Previous Thread
Next Thread
Print Thread
Rate Thread
Poor idle on '73 750 Tiger #494689
06/19/13 6:40 pm
06/19/13 6:40 pm
Joined: Jul 2011
Posts: 134
TN/VA/FL USA
F
fried okra Offline OP
BritBike Forum member
fried okra  Offline OP
BritBike Forum member
F

Joined: Jul 2011
Posts: 134
TN/VA/FL USA
I picked up a nice original single carb 750cc '73 Tiger today. The bike starts easily and runs great at all throttle openings but won't idle well. The bike runs ragged and uneven at idle. Idle speed is roughly 1000 rpm.

The 930 AMAL was replaced about 10 years ago and maybe has a couple thousand miles on it. It idles best with the mix screw turned out about one quarter (1/4) turn from seated.

Any thoughts on where to start looking??

thanks,
fried okra

Support Your #1 BritBike Forum!

Check out British motorcycles for sale:
British Motorcycles on e-Bay UK, British motorcycles on e-Bay North America
Check out British motorcycles for sale:
British Motorcycles on e-Bay UK, British motorcycles on e-Bay North America
Re: Poor idle on '73 750 Tiger [Re: fried okra] #494691
06/19/13 6:47 pm
06/19/13 6:47 pm
Joined: Dec 2004
Posts: 9,671
Scotland
kommando Online content
BritBike Forum member
kommando  Online Content
BritBike Forum member

Joined: Dec 2004
Posts: 9,671
Scotland
#78 drill through the pilot jet followed by a good spray of carb cleaner through the passageways making sure they are clear. Modern fuels do not like small jets and try to block them.

Re: Poor idle on '73 750 Tiger [Re: kommando] #494693
06/19/13 6:53 pm
06/19/13 6:53 pm
Joined: Jul 2011
Posts: 134
TN/VA/FL USA
F
fried okra Offline OP
BritBike Forum member
fried okra  Offline OP
BritBike Forum member
F

Joined: Jul 2011
Posts: 134
TN/VA/FL USA
Thanks....I've got some #78 drill bits ordered, can hardly wait for them to get here in about a week!!!!!

fried okra

Re: Poor idle on '73 750 Tiger [Re: fried okra] #494732
06/20/13 12:33 am
06/20/13 12:33 am
Joined: Sep 2011
Posts: 1,016
New Zealand
Excalibur Offline
BritBike Forum member
Excalibur  Offline
BritBike Forum member

Joined: Sep 2011
Posts: 1,016
New Zealand
With needing to be 1/4turn from seated for best idle, it sounds like blockage to me too. Turning the mixture screw inward cuts the air supply off to the idle circuit, so either the fuel is restricted or there's an air leak elsewhere (manifold, etc).

I hear the US gasoline has an alcohol content. That won't be good news for carburetors, especially zinc based ones. I speculate that even the small amount of alcohol in the fuel will be attracting moisture. I run alky in the dragbike so I see the damage it can do. The carbs get drained EVERY time on that bike.
So I just wonder how the Amals are they holding up to the US fuel?

Re: Poor idle on '73 750 Tiger [Re: Excalibur] #494740
06/20/13 1:21 am
06/20/13 1:21 am
Joined: Nov 2008
Posts: 2,866
Bishop, Calif.
D
desco Offline
BritBike Forum member
desco  Offline
BritBike Forum member
D

Joined: Nov 2008
Posts: 2,866
Bishop, Calif.
@ Excalibur
They are holding up just fine. Bored and sleeved to correct wear problems, an annual PROPER cleaning and a bit of spring time general maintenance works miracles. I have access to aviation gas and I quit using it as it plugged up the idle jet all the time. I don't know how planes run on it.
PS Bless you for keeping Triumph in the records book.


1968 T120R
1972 T120RV
Any advice given is without a warranty expressed or implied.

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
Powered by UBB.threads™ PHP Forum Software 7.6.2