Britbike forum

Classic British SparesKlempf British PartsBaxter CycleBritBike Sponsor SteadfastCyclesSRM EngineeringLucas Classic MotorcycleIndustrial tec supplyHepolite PistonsThe Bonneville Shop

Upgrade your membership to: Premium Membership | Gold Membership | Life Membership | Vendor Membership | Site Sponsor Membership
Member Spotlight
Kenny
Kenny
Oklahoma
Posts: 33
Joined: July 2003
ShoutChat
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Top Posters(30 Days)
Allan G 68
quinten 62
DavidP 55
Top Likes Received (30 Days)
Cyborg 24
Allan G 18
Newest Members
neilhart, Dguzzi, Peter McCarthy, Seb Clare, Trevi
11,779 Registered Users
Who's Online Now
5 members (Chip H, Russ, Alex Lynch, L.A.B., scott garland), 42 guests, and 83 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Page 1 of 2 1 2
#851951 06/20/21 12:21 am
Joined: Oct 2012
Posts: 5,832
Likes: 139
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 5,832
Likes: 139
My 79 T140D, on a shift from first to second at a moderate speed the shifter hangs up in neutral.This happens about 50% of the time. Sometimes a second try finds second, sometimes not...If the bike accelerates briskly to a higher rpm it seems ok All other gears shift ok up or down. the clutch does not drag, neutral is not difficult to find stopped or moving ,chains are newer and in adjustment...No unusual noises, GL 4 90 gear oil...
What do you think?


79 T140D, 96 900M Ducati ,61 A10 .On a bike you can out run the demons.."I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
Support Your #1 BritBike Forum!

Check out British motorcycles for sale: British Motorcycles on e-Bay UK, British motorcycles on e-Bay North America
Joined: Jan 2004
Posts: 5,077
Likes: 91
D
Britbike forum member
Offline
Britbike forum member
D
Joined: Jan 2004
Posts: 5,077
Likes: 91
Does this year have the neutral light switch? The plunger could be hanging up.

Joined: Jan 2017
Posts: 1,655
Likes: 71
T
Britbike forum member
Offline
Britbike forum member
T
Joined: Jan 2017
Posts: 1,655
Likes: 71
Hi Hillbilly, Rusted, weak, broken shifter centering springs can cause this. I can't explain why not in all gears. I find that puzzling.

Rust out, rust weakness of springs is very common on these bikes. Your bike would have come with the thicker curved springs. 57-7051
Don


1973 Tiger 750
1 member likes this: Lorenzo
Joined: Aug 2016
Posts: 258
Likes: 27
T
Britbike forum member
Offline
Britbike forum member
T
Joined: Aug 2016
Posts: 258
Likes: 27
Is this something that has just started happening? If you have the wrong "pointed" index plunger, you might get this happening. The round nosed 57-7020 is the correct one for the low inertia camplate you will have (better still to use the T160 parts, 57-4226 plunger, 57-4459 spring and 57-4227 housing). Having said that DMadigan may well be right, '79 was the first year of the neutral switch.

Joined: Oct 2012
Posts: 5,832
Likes: 139
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 5,832
Likes: 139
Yes the bike has a functioning neutral light. The centering springs looked ok three years ago..The bike isn't ridden more than about 1000 miles a year but gets a good workout when ridden. When not ridden the bike is parked in my heated shop...The bike has rear set controls but nothing is sloppy or binding...
Moving the lever by hand it appears to have a firm centering action
It's a problem that seems to be worse this year. Why does the problem seem to disappear when ridden more aggressively?...
I suppose it's best just to have a look inside..


79 T140D, 96 900M Ducati ,61 A10 .On a bike you can out run the demons.."I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
1 member likes this: TinkererToo
Joined: Jan 2004
Posts: 5,077
Likes: 91
D
Britbike forum member
Offline
Britbike forum member
D
Joined: Jan 2004
Posts: 5,077
Likes: 91
The neutral switch that I have has a brass body and pin. The plunger hole could have worn or the pin could have developed a ridge that makes it hang up on the edge of the hole. Either way, the pin could be sticking making the shift hard when lightly moved but more aggressive shifting masks the problem.
I would remove the switch and replace with a plug to test before opening up the box.

1 member likes this: TinkererToo
Joined: Oct 2012
Posts: 5,832
Likes: 139
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 5,832
Likes: 139
Originally Posted by DMadigan
The neutral switch that I have has a brass body and pin. The plunger hole could have worn or the pin could have developed a ridge that makes it hang up on the edge of the hole. Either way, the pin could be sticking making the shift hard when lightly moved but more aggressive shifting masks the problem.
I would remove the switch and replace with a plug to test before opening up the box.
Your reasoning sounds good..... I had the gearbox apart when rebuilding the engine a few years ago..l don't think it's possible to remove the switch unless the inner cover is removed?


79 T140D, 96 900M Ducati ,61 A10 .On a bike you can out run the demons.."I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
Joined: Oct 2012
Posts: 5,832
Likes: 139
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 5,832
Likes: 139
DMadigan wins the kewpie doll for the closest answer to the problem..Not exactly what he said but it appears to be contact between the neutral light switch body and the camplate..Strange that it was ok for a few years and just recently acted up...

3E6EFFC9-A1CA-4379-8CBE-88B73ECDE7A5.jpeg

79 T140D, 96 900M Ducati ,61 A10 .On a bike you can out run the demons.."I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
Joined: Mar 2006
Posts: 4,952
Likes: 48
L
Britbike forum member
Online Content
Britbike forum member
L
Joined: Mar 2006
Posts: 4,952
Likes: 48
Originally Posted by Hillbilly bike...
it appears to be contact between the neutral light switch body and the camplate...


The neutral switch is operated by a pin on the quadrant and is what would have made that light score mark on the switch body, not the camplate (which is the other side of the quadrant).

[Linked Image from cdn.shopify.com]

[Linked Image from i.postimg.cc]

Joined: Oct 2012
Posts: 5,832
Likes: 139
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 5,832
Likes: 139
Whatever, you knew what I meant...and it's quite a score, it left a noticeable mark on #28 in the diagram.. The switch plunger moves smoothly so it'll get reused...inner cover needs to be pulled to get at the switch...


79 T140D, 96 900M Ducati ,61 A10 .On a bike you can out run the demons.."I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
Joined: Jan 2004
Posts: 5,077
Likes: 91
D
Britbike forum member
Offline
Britbike forum member
D
Joined: Jan 2004
Posts: 5,077
Likes: 91
If the switch is operated by the pin on the quadrant, would you know why the stop at 1st on the "low inertia" camplate is so long? It hits the plunger body and keeps the plate from being rotated fully. Not a problem when building the gearbox but the camplate can be made from a smaller piece otherwise. Makes it larger in diameter than the round plate.

Joined: Mar 2006
Posts: 4,952
Likes: 48
L
Britbike forum member
Online Content
Britbike forum member
L
Joined: Mar 2006
Posts: 4,952
Likes: 48
Originally Posted by DMadigan
If the switch is operated by the pin on the quadrant, would you know why the stop at 1st on the "low inertia" camplate is so long? It hits the plunger body and keeps the plate from being rotated fully. Not a problem when building the gearbox but the camplate can be made from a smaller piece otherwise. Makes it larger in diameter than the round plate.

The 'low inertia' (57-4889, parts book '77-on) camplate appears to be the 'T160' pattern camplate where the ear would operate the T160 neutral switch.

http://vintagebikemagazine.com/tech...-of-a-4-speed-to-a-5-speed-transmission/


"Tech Note: There have been two iterations of the 5-Speed camplate. The one on the left is the will see most often while the one on the right is from a T160. The standard camplate can only be removed or installed after the mainshaft high gear is removed. The T160 camplate can be removed and replaced with the high gear in place. Because the T160 camplate is expensive, many technicians modify the early camplate to the T160 condition by grinding away a part of the camplate. When using the “full” round camplate you want to use the pointed plunger (57-7020 plunger, 57-4459 spring and 57-4400 housing). When using the lightened camplate you should use the rounded nose plunger (57-4226 plunger, 57-4459 spring and 57-4227 housing) from the T160. The T160 camplate has an ear that operates the neutral switch and might require attention to clearance when fitting."

(57-7020, 57-4459 and 57-4400, however, continued to be listed in the parts books for T140 including Harris)

Joined: Jan 2004
Posts: 5,077
Likes: 91
D
Britbike forum member
Offline
Britbike forum member
D
Joined: Jan 2004
Posts: 5,077
Likes: 91
So it seems that I have to keep the long stop on the reverse pattern camplate for the T160s.

Joined: Oct 2012
Posts: 5,832
Likes: 139
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 5,832
Likes: 139
My bike's plate looks just like this one

[img]https://www.classicbritishspares.co...sembly-57-4889-1973-82-t140-tr7-t160-750[/img]


79 T140D, 96 900M Ducati ,61 A10 .On a bike you can out run the demons.."I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
Joined: Mar 2006
Posts: 4,952
Likes: 48
L
Britbike forum member
Online Content
Britbike forum member
L
Joined: Mar 2006
Posts: 4,952
Likes: 48
Originally Posted by DMadigan
So it seems that I have to keep the long stop on the reverse pattern camplate for the T160s.

A reverse camplate would mean the neutral switch operated between 4th and 5th though, wouldn't it?

Joined: Jan 2004
Posts: 5,077
Likes: 91
D
Britbike forum member
Offline
Britbike forum member
D
Joined: Jan 2004
Posts: 5,077
Likes: 91
Looking at the T160 parts book from CBS, the 1st gear stop points half a gear shift toward the inner gearbox cover when in neutral. Since the reverse camplate turns the other way it will be pointing half a gear shift toward the primary cover. So the elongated stop is not needed since it cannot work with the reverse camplate. I do not see many T160 owners wanting a reverse camplate anyway.

Joined: Aug 2016
Posts: 258
Likes: 27
T
Britbike forum member
Offline
Britbike forum member
T
Joined: Aug 2016
Posts: 258
Likes: 27
The 57-7020 is NOT the pointed plunger, it is 57-3660, and its this that should be used with the round camplate. The 57-7020 is also longer, I have had a pre-unit converted gearbox where the long plunger bound on the edge of the round camplate.

Joined: Jan 2004
Posts: 5,077
Likes: 91
D
Britbike forum member
Offline
Britbike forum member
D
Joined: Jan 2004
Posts: 5,077
Likes: 91
The maximum diameter of the round plate and T160 plate is the same between gear stops.
The 57-7020 and 57-3660 plungers use the same spring, housing and washer so I do not see why one would work and not the other. Perhaps the plunger housing sits closer to the camplate in the converted gearbox.

Joined: Aug 2016
Posts: 258
Likes: 27
T
Britbike forum member
Offline
Britbike forum member
T
Joined: Aug 2016
Posts: 258
Likes: 27
Hello Dave,
It did, but the 57-7020 plunger is longer, the spring became coilbound (as I remember). Changing the plunger cured the problem. Anyone want some spare, new, 57-7020 plungers?
Cheers,
Mick.

Joined: Oct 2008
Posts: 7,242
Likes: 148
Britbike forum member
Offline
Britbike forum member
Joined: Oct 2008
Posts: 7,242
Likes: 148
I guess I'll keep finding neutral the old fashioned way, by poking the lever up and down until the light changes just as I find it. laughing


Knowledge speaks. Wisdom listens.

72 T120V cafe project "Mr. Jim"
72 T150V "Wotan"
92 BMW K100rs "Gustav"
Joined: Mar 2011
Posts: 415
Likes: 22
L
Britbike forum member
Offline
Britbike forum member
L
Joined: Mar 2011
Posts: 415
Likes: 22
I'm real interested in what you do to fix this, because my 79 T140D does this too. It hangs up shifting out of first, mostly when it is hot, and it may then take a couple tries to get into second.

I haven't even looked at this yet so I ask an obvious question--Is the switch adjustable for depth of install? if so, maybe lessen the installed depth a bit? or should the whole thing be replaced? or should the interfering part (apparently the quadrant or its pin) be "clearanced"?

My parts book lists and shows a picture of the switch as 60-7180, but then there are 3 other parts listed and noted as not pictured:

57-7041 the operating pin--is this the pin mounted in the quadrant shown above by the green arrow?

57-7046 the distance tube neutral switch, and

70-1335, a washer.

Are these parts relevant to the problem?

Last edited by linker48x; 07/24/21 1:29 am.
Joined: Oct 2012
Posts: 5,832
Likes: 139
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 5,832
Likes: 139
The switch depth is adjustable...my previous posts show the switch scored by improper clearance....There's a pointed pin pressed into the quadrant that contacts the switch in the neutral position. copper sealing washer, distance piece?


79 T140D, 96 900M Ducati ,61 A10 .On a bike you can out run the demons.."I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
Joined: Mar 2006
Posts: 4,952
Likes: 48
L
Britbike forum member
Online Content
Britbike forum member
L
Joined: Mar 2006
Posts: 4,952
Likes: 48
Originally Posted by linker48x
My parts book lists and shows a picture of the switch as 60-7180, but then there are 3 other parts listed and noted as not pictured:

57-7041 the operating pin--is this the pin mounted in the quadrant shown above by the green arrow?

Yes.


Originally Posted by linker48x
57-7046 the distance tube neutral switch,

57-7046 is a distance tube (spacer) but it isn't listed or illustrated in later parts books.

Originally Posted by linker48x
and 70-1335, a washer.


"30...70-1335...Washer-For Switch''.

[Linked Image from i.postimg.cc]

Joined: Mar 2011
Posts: 415
Likes: 22
L
Britbike forum member
Offline
Britbike forum member
L
Joined: Mar 2011
Posts: 415
Likes: 22
And anyone have advice on proper clearance, and how to get it? I can’t locate this in my shop manuals. Sorry in advance for the thread hijack. Bike is up on the stand for the next few days, thought this would be a good time to address this.

Joined: Sep 2008
Posts: 143
Likes: 3
L
Britbike forum member
Offline
Britbike forum member
L
Joined: Sep 2008
Posts: 143
Likes: 3
I don't think there is a proper clearance as such.......the way I did mine was to set the camplate in neutral and thread in the switch just enough to close the switch contacts (and no more) - check it out with a multimeter - .tighten the locknut against the copper sealing washer -.and re-check.

Although distance piece 57-7046 is listed for the switch, I understand it was used (together with a 3/8" screw) only.when substituting a switch not required..


1978 T140E
1979 TR7V
1960 Royal Enfield Bullet 350
1973-81 (6x) Bultacos
Waste not, want not.........Thrift is a virtue.
Page 1 of 2 1 2

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