ATD backplate

Grash

Forum User
Non-VOC Member
One ear has dropped off my backplate (Comet) and the other ear has a fine crack leading to the pivot pin. It is now all in pieces. Does anyone know where I can get just the backplate? Contacted "Roy" from MPH ads., but he says he has a huge backlog of work (doesnt sound very well) and cannot help. Any suggestions please...
 

Grash

Forum User
Non-VOC Member
Many thanks. By the way I am a new member but message shows me as nonmember. How do I change my status?
 

Grash

Forum User
Non-VOC Member
A quick post script in case anyone has had a similar problem. Took the offending ATD backplate to my local welders (Specialist Welding, Hanney Road, Steventon, Oxon 01235 820821) and a chap called Frank thought he could repair it. Sure enough, one week later, I returned to find he had made a new "ear", welded it into place and welded the crack in the opposite ear. This for the very reasonable sum of £20. All I had to do was dress back the welds to ensure full movement of the toggles and to cut away a little of the tufnel gear to accomodate the thickness of the weld (I thought it better than reducing the weld thickness). All now looks very good. Nice to find a company willing to accept a challenge.

Grash
Comet
 
Last edited:

ossie

Well Known and Active Forum User
VOC Member
any chance of a photo to see if your weld up was better than my attempt.
OSSIE
 

Grash

Forum User
Non-VOC Member
Here be before and after. The replacement ear is the lower left one. DSCF0026.jpgDSCF0023.jpg
 

ossie

Well Known and Active Forum User
VOC Member
yep looks just like mine did.
i put a bit more weld on the inside of the ear and then cleaned it up,
also on the outside radius as it dont matter out there .
where the weld was a bit full on the inside i rounded off the bob weights to give the ears as much strength as i could.
i think the cracks occured because the metal was not of a quality that liked being bent at such an abrupt angle.
as i worked in a press shop this use to happen when the company changed the steel suppliers.
to save money it never worked as the jobs came back rejected inferior material.
like series d fiberglass etc.
shame when someone else,s shortcuts let you down.
ive not put it on the bike yet as the one i have on seems to be working ok,but it does keep reving a bit after i close the throttle after a run,
wich can be caused by the springs on the atd not pulling it back to its stops.
time will tell. or when i get the cover off to have a look.
i hate taking it down when its going with all its hicupps,
 

Grash

Forum User
Non-VOC Member
I know what you mean, if it aint broke (too much!) don't fix it. It's interesting that the ear that fell off and the ear with the crack were both adjacent to the pivot pins. The crack ran from the radius, at the point where the angle limiting lug strikes the ear, to the pivot hole. This is the fully retarded stop. I wonder if the repeated striking of the sharp corner onto the radius helps to initiate the crack. If so then radiusing the moving lug may prevent the problem in the first place.
It will take a while before I check it as I am still struggling to remove the outer shell of the timing side roller bearing. I have tried to dress back the "staking" marks but even when heated to 200C it doesnt want to come out (very difficult to give any impetous from the oilpump side.) Is staking really needed if the interference fit is good. Is Locktite enough?
 

ossie

Well Known and Active Forum User
VOC Member
if your replacing the bearing grind the bearing with a dremmel or something like it in a few places from the inside to nearly out to the ally casting and this will sometimes weaken the ring and you can carefully break it out.
good luck what ever way you try.
 
Top