Britbike forum

Classic British Spares Klempf British PartsBaxter Cycle BritBike Sponsor SteadfastCyclesSRM Engineering Lucas Classic Motorcycle Industrial tec supply Hepolite Pistons The Bonneville ShopLowbrow Customs

Upgrade your membership to: Premium Membership | Gold Membership | Life Membership | Vendor Membership | Site Sponsor Membership
Member Spotlight
royaloilfield
royaloilfield
Trenton, New Jersey
Posts: 1,217
Joined: February 2007
ShoutChat
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Top Posters(30 Days)
quinten 91
Rohan 65
Top Likes Received (30 Days)
quinten 13
Newest Members
vanGinneke, Gearhard, yornocT120R, robert wilby, Jonah A
11,839 Registered Users
Who's Online Now
5 members (Dave Comeau, bill50cal, quinten, TR7RVMan, bsalloyd), 25 guests, and 71 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
#836887 01/16/21 12:58 am
Joined: Jun 2020
Posts: 6
Britbike forum member
OP Offline
Britbike forum member
Joined: Jun 2020
Posts: 6
Hey guys, I have brought a 1965 triumph T1 20 C back to life. It is a 6 V system still. I have done a Mikuni carb swap. The bike starts on the first kick. The problem is between 1000 I and 3500 RPMs the bike is sluggish. 3500 and up the bike runs fantastic. I have tuned the carbs to the best of my ability and nothing I do will remedy the situation. I really don’t experience much of a difference no matter if I change jets or needle position. I’m starting to look towards the electronics. Is there a way I can test the coils while it’s running? The reason I think it’s ignition is because it is always at 3500 RPMs when it comes to life. I am still running points and have set the timing and adjusted the valves.

Thank you for any and all useful information.

Bud


Bud ✌️
Triumphs on eBay
Joined: Nov 2012
Posts: 2,200
Likes: 79
K
Britbike forum member
Offline
Britbike forum member
K
Joined: Nov 2012
Posts: 2,200
Likes: 79
Why did you swap to the Miks? Do you still have the original carbs?

Joined: Jun 2020
Posts: 6
Britbike forum member
OP Offline
Britbike forum member
Joined: Jun 2020
Posts: 6
I switched to Mikuni because I’m familiar with them. Yes I still have the og


Bud ✌️
Joined: Dec 2013
Posts: 5,745
Likes: 116
DOPE
Offline
DOPE
Joined: Dec 2013
Posts: 5,745
Likes: 116
bud, did the performance decrease accompny the carb swap?

if the problem is rpm related i suspect issuez with the auto advance unit. does it advance abd retard normalli y? is it corroded ?


i'm old enough to remember when patriotism meant not trying to overthrow the government.
1 member likes this: Allan G
Joined: Jun 2020
Posts: 6
Britbike forum member
OP Offline
Britbike forum member
Joined: Jun 2020
Posts: 6
Kevin. I have no idea how the bike ran prior to the switch. It had not run since 1988. This was truly a barn/shed find. It is not corroded. I don’t know how to check the auto advance unit.

Bud ✌️


Bud ✌️
Joined: Sep 2013
Posts: 3,338
Likes: 142
Q
Britbike forum member
Online Happy
Britbike forum member
Q
Joined: Sep 2013
Posts: 3,338
Likes: 142
1965 triumph T120 C .
cant remember , was this a 6 volt battery ignition
or a 6 volt ET ignition ...

in either case I would look to the AAU as the problem .
these AAUs were not built to stand the test of time .

Joined: Jun 2020
Posts: 6
Britbike forum member
OP Offline
Britbike forum member
Joined: Jun 2020
Posts: 6
Quinten, sorry bout that. Yes it is a 6V system still.


Bud ✌️
quinten #836900 01/16/21 3:49 am
Joined: Jun 2020
Posts: 6
Britbike forum member
OP Offline
Britbike forum member
Joined: Jun 2020
Posts: 6


Bud ✌️
Joined: Oct 2008
Posts: 7,307
Likes: 164
Britbike forum member
Offline
Britbike forum member
Joined: Oct 2008
Posts: 7,307
Likes: 164
Wrong slides? You don't describe the problem by throttle position, but just off idle is where the slide cutaways control things. I had Mikunis on my A65. 2.5 slides allowed me to leave the driveway sooner, but 3 accelerated better once warmed up.
But, definitely check out your advance unit. Rotate the cam by hand to see if it moves easily. Lubricate and check/replace the springs.


Knowledge speaks. Wisdom listens.

72 T120V cafe project "Mr. Jim"
72 T150V "Wotan"
92 BMW K100rs "Gustav"
Joined: May 2013
Posts: 8,194
Likes: 182
A
Britbike forum member
Offline
Britbike forum member
A
Joined: May 2013
Posts: 8,194
Likes: 182
Check the AAU. Strip it and ensure that the surfaces are clean, corrosion free and free to rotate against each other without having any wobble (too much free play)

Get yourself some Auto advance springs from Eurotrash jambalaya website (they are based in the US) they do a lot of cool stuff for vintage Brit bikes. Their AAU springs reach full advance at around 3000 revs, with a tweak you can get them full advance at 3500 which I found better for my A65. Stock springs reached full advance at 2000 and it is too soon with modern pump gas.

Apply a light grease to the shaft before fitting the cam. Then refit the AAU and points. You may need to strobe time on both cylinders (did triumphs get the 4CA points and cam?) check your points gap is 0.015” when fully open.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (now rebuilt)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Joined: Jun 2020
Posts: 6
Britbike forum member
OP Offline
Britbike forum member
Joined: Jun 2020
Posts: 6
Thank you David and Allan for your replies. David, I thought it may be the slide or the needle jet. Will be taking the carbs apart to see which components I need to buy. As far as the throttle position it doesn’t really matter it is always sluggish until 3500 rpm. Then BOOM it roars to life. Alan, I will checking out the ignition systems for the issues you point out (pun intended). Let’s say I have 14 degrees of timing at idle. What would stop it from advancing until 3500?


Bud ✌️

Moderated by  John Healy 

Link Copied to Clipboard
Job CycleBritish Cycle SupplyMorries PlaceKlempf British PartsPodtronicVintage MagazineBSA Unit SinglesBritBike SponsorBritish Tools & FastenersBritBike SponsorBritBike Sponsor






© 1996-2021 britbike.com
Powered by UBB.threads™ PHP Forum Software 7.7.5