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Shifter Cam Plate #288164
12/10/09 12:45 am
12/10/09 12:45 am
Joined: Jun 2009
Posts: 33
Ontario Canada
B
BritinAlma Offline OP
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BritinAlma  Offline OP
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Joined: Jun 2009
Posts: 33
Ontario Canada
Hi Guys
I have been rebuilding the gearbox on my 69 Bonnie when I inspected the shifter cam plate I found it worn and decided to change it , I managed to find one on e-bay but when it arrived it was bigger and had less detents in it , I looked in my manual and it seems to picture my origional cam plate and uses one of the detents to hold the plate in place when putting the gearbox bad together , my question is will the new bigger plate work and why is it different ?
Thanks Max


Why ? because thats what I like
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Re: Shifter Cam Plate [Re: BritinAlma] #288166
12/10/09 12:49 am
12/10/09 12:49 am
Joined: Jan 2004
Posts: 3,646
ca, us
D
DMadigan Offline
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DMadigan  Offline
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Joined: Jan 2004
Posts: 3,646
ca, us
At some point they changed the shift forks from brass with rollers in the camplate to steel with no rollers. Could that be the difference?

Re: Shifter Cam Plate [Re: DMadigan] #288171
12/10/09 1:16 am
12/10/09 1:16 am
Joined: Jan 2006
Posts: 1,901
Asheville, NC
Mike Baker Offline
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Mike Baker  Offline
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Joined: Jan 2006
Posts: 1,901
Asheville, NC
Do you have a 4 speed? I think they are all the same. Well, at least the ones I've seen. I've interchanged bronze with steel forks without having any problems with the cam.
What was worn on the cam?
Mike

Last edited by mblab; 12/10/09 1:23 am.
Re: Shifter Cam Plate [Re: Mike Baker] #288173
12/10/09 1:37 am
12/10/09 1:37 am
Joined: Jun 2009
Posts: 33
Ontario Canada
B
BritinAlma Offline OP
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BritinAlma  Offline OP
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Joined: Jun 2009
Posts: 33
Ontario Canada
Yes it is a 4 speed and my shifter fork are steel with rollers , the shifter fork groove is worn as well as the outside edge where the sprung plunger rides , it would probably be Ok but I figured that as I had it in my hand now would be the time to change it instead of second guessing myself the middle of next summer
Max


Why ? because thats what I like
Re: Shifter Cam Plate [Re: BritinAlma] #288184
12/10/09 3:06 am
12/10/09 3:06 am
Joined: Nov 2008
Posts: 148
Oregon
M-Runner Offline
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M-Runner  Offline
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Joined: Nov 2008
Posts: 148
Oregon
The early {Pre 69} forks were steel with free rollers, replaced with alloy forks and fixed rollers. The cam plate and detent plunger were also changed at this point. The cam plate has fewer notches.

I run these later componants in all of my mid/late 60's bikes. I get very few false neutrals or missed shifts:

Shift Cam Plate 57-4055
Detent Plunger 57-3660
Fork (L/S) 57-4307
Fork (M/S) 57-4308

Polish the edge of the shift cam where the plunger rides, to a high finish.

Re: Shifter Cam Plate [Re: BritinAlma] #288185
12/10/09 3:17 am
12/10/09 3:17 am
Joined: Jan 2004
Posts: 3,646
ca, us
D
DMadigan Offline
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DMadigan  Offline
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D
Joined: Jan 2004
Posts: 3,646
ca, us
The groove from the indexing plunger probably makes it shift smoother than originally. I do not know why in Tartarus they did not put a roller on the end. It could be oriented by extending the cylinder over the sides of the camplate. The fork groove is a problem. It might let the gears disengage. Triumphs do not have undercut dogs to help keep them from pushing apart under load.

Re: Shifter Cam Plate [Re: DMadigan] #288187
12/10/09 3:37 am
12/10/09 3:37 am
Joined: Mar 2005
Posts: 10,084
Boston, Massachusetts
J
John Healy Offline

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John Healy  Offline

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J
Joined: Mar 2005
Posts: 10,084
Boston, Massachusetts
David is right, Triumph four speed gears are not back cut, but this was corrected with the five speed box. The Triumph five speed gears are back cut.

The 57-4055 is a forging and in IMHO a quality piece. It should be used with the 57-3660 detent as suggested by Mr-runner above. It is my favorite 4 speed camplate!


Re: Shifter Cam Plate [Re: John Healy] #288280
12/10/09 6:54 pm
12/10/09 6:54 pm
Joined: Oct 2003
Posts: 11,167
North Georgia, USA
RF Whatley Offline
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RF Whatley  Offline
BritBike Forum member
Joined: Oct 2003
Posts: 11,167
North Georgia, USA
Additionally, the lack of the extra neutral position between 2nd and 3rd will not keep you from setting the camplate in that position for assembly. Obviously the camplate can still be set in that position, the notch simply makes it stupid-proof. laughing

The truth is that the gear teeth on the quadrant that interface with the gear on the rear of the camplate are so course that the camplate being off 1 degree really doesn't slow you down on assembly. The large teeth allow for a great deal of inaccuracy during the quadrant timing process, and the job goes just as fast.

So there is nothing to loose in the newer design camplate and certainly smoother shifting to gain.

bigt


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA

"Shop Boy" at Rodi British Bikes
Re: Shifter Cam Plate [Re: RF Whatley] #288307
12/10/09 10:12 pm
12/10/09 10:12 pm
Joined: Jun 2009
Posts: 33
Ontario Canada
B
BritinAlma Offline OP
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BritinAlma  Offline OP
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Joined: Jun 2009
Posts: 33
Ontario Canada
Thanks
this is the kind of answer I was hoping for
Max


Why ? because thats what I like
Re: Shifter Cam Plate [Re: John Healy] #318336
06/14/10 9:34 am
06/14/10 9:34 am
Joined: Oct 2001
Posts: 24
Scotland
DC Offline
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DC  Offline
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Joined: Oct 2001
Posts: 24
Scotland
Originally Posted By: John Healy

The 57-4055 is a forging and in IMHO a quality piece. It should be used with the 57-3660 detent as suggested by Mr-runner above. It is my favorite 4 speed camplate!

I need to replace the original camplate in my '68 T120.Although I can get the correct camplate for that year, I would prefer to take the opportunity to improve the shifting.
From reading the above, it would appear that the 57-5055 cam and 57-3660 plunger are compatible with all of the older components?
Is that correct? (I'd rather not have to replace the selector forks and plunger housing if not necessary)
Thanks

Re: Shifter Cam Plate [Re: DC] #318462
06/14/10 11:00 pm
06/14/10 11:00 pm
Joined: Oct 2003
Posts: 11,167
North Georgia, USA
RF Whatley Offline
BritBike Forum member
RF Whatley  Offline
BritBike Forum member
Joined: Oct 2003
Posts: 11,167
North Georgia, USA
Without taking the time to look up the parts you mentioned, IME almost all the 4-speed parts since the mid-1950's are interchangeable... provided they are of the same ratio set and tooth counts.

There are minor annoying differences like the layshaft resident speedo drive, and the longer journals of the pre-unit layshafts. But generally speaking shifter camplates and plungers would be a direct swap.


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA

"Shop Boy" at Rodi British Bikes

Moderated by  John Healy 


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