Broken bottom Yoke / Triple tree

If I am not mistaken , All of the broken fork yokes were 2015's !!! Maybe the same person over torqueing them ??? How about that one folks ? But why that l/h side always ? Same side same person ? Just wondering that's all , but so far all 2015 year.

I'm thinking they should be able to run the VIN and see who assembled the bike and marked bolts with yellow paint.
 
Well, I said in a previous post on this topic that the root cause looked like over torquing to me. Those 3 bolts can apply immense torque to that thin alloy.

The photos I’ve seen of the cracked yolks show quite a gap in the crack where the bolts are clearly pulling the material away.

Having said that though, I looked at pics of the anniversary CR and the yokes do look different. Are they Dominator yokes? Or has the factory changed the design across the range? It might be worth enquiring as it would seem a good idea to replace with the latest version if a weakness has been designed out.
 
Hello Together,

the torque for the bottom yoke is round about 12 Nm, if you torque more the sleeve inside will be compressed and fork can not work properly.
The torque for the upper yoke is roundabout 16 Nm not more.
I have on my racing bikes the same designed yokes ( with triple clamps) and Öhlins.
The engineer from Öhlins tell´s me that´s is enough.

panetone
 
Good point panetone, that’s probably why there’s 3 bolts and a big deep yoke, cos that way 12nm is enough.

But the flip side is that if you don’t know that, massive over tightening is really easy to do!

12nm isn’t a great amount, I would definitely have tightened them more than that previously !
 
Ok sounds good , Service Manual states 20 Nm . Maybe no problem on RWU forks ? In fact , I think all broken yokes are USD forks !
 
Investigation into this is ongoing, when we know more you will be the first to know.

In the meantime if anyone has an issue of course parts will be supplied FOC, regardless of the age of the bike.

Simon
 
Investigation into this is ongoing, when we know more you will be the first to know.

In the meantime if anyone has an issue of course parts will be supplied FOC, regardless of the age of the bike.

Simon
Stepping up to the plate. That's fantastic.
 
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If I am not mistaken , All of the broken fork yokes were 2015's !!! Maybe the same person over torqueing them ??? How about that one folks ? But why that l/h side always ? Same side same person ? Just wondering that's all , but so far all 2015 year.

Well, mine is a 2013 CR and the Left side lower yoke (triple tree) is cracked exactly as mentioned above. 4000mile bike - no rough riding, never touched these bolts either.
Sent Norton a request, will be interesting to see the response since so much has changed at the factory.

Anyone know of where else to buy a new lower yoke, if Norton fdon't come through?
 
Hi Bushman , I hope Norton will come through for you . Do you think that over-torqueing is the cause for this ? There are members with 20,000 miles on their bikes and yokes ok still. I have over 17,000 miles on my bike (November 2014 build) .
Well, mine is a 2013 CR and the Left side lower yoke (triple tree) is cracked exactly as mentioned above. 4000mile bike - no rough riding, never touched these bolts either.
Sent Norton a request, will be interesting to see the response since so much has changed at the factory.

Anyone know of where else to buy a new lower yoke, if Norton fdon't come through?
 
Since this issue could be deadly, it would be worthwhile investigating to see if there are other triple trees that could be retro-fitted. Simply putting a new part on that is made to the same design as the old broken one seems a recipe for trouble. Big question, has anyone at Norton redesigned this part to avoid the failure?
If it's just a not yet broken but identical to original part, I wouldn't trust my life with it.

Perhaps with a bit of modification there is a Suzuki , Yamaha Honda or Kawasaki part that will fit and work.
Those ones don't come apart unless you run into the back of a truck.
Or one could install an entire front end such as the Showa Big Piston unit and get the anti-dive feature, which is very nice.
These are fitted to late model GSXRs, Thruxton Rs and a few other bikes.
I installed a set on an original Commando frame, wasn't a bad job at all, bit of machining.
End result, it's a very light, high performance front end. And the triple trees won't break.
Another thought-
Perhaps it would be good to ask Ohlins about this. The front end is supposed to be Ohlins and they make quality items. Typically the triple trees come with the forks, so the triple trees ought to be Ohlins as well?

Glen
 
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I bought my 961 with 1000 miles and the bottom yoke broken on both sides. I had a new reinforced yoke built in Italy by a specialized manufacturer.
He still has the design and can still produce it
 
Broken bottom Yoke / Triple tree
Broken bottom Yoke / Triple tree
Broken bottom Yoke / Triple tree
Broken bottom Yoke / Triple tree
Broken bottom Yoke / Triple tree
Broken bottom Yoke / Triple tree
 
Egads, a double whammy!
Did this happen before Norton went belly-up last year?
Were you able to contact Norton about the failed unit?
The new triple tree looks well made.
 
This happened to Gary, the guy I mentioned who’s touring on a Cafe Racer (2015?) . I think his failed both sides - he’s not on the forum. Top/bottom yokes are solid billet ally, along with many of the engine assemblies - much more expensive way to manufacture but you would have thought much stronger. Not strong enough it seems. Catastrophic failure if these let go on the road!
Broken bottom Yoke / Triple tree
 
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Has anyone contacted Ohlins to see if they did supply the forks to Norton and, if so, did they supply yokes with the package?

Glen
 
The anniversary billet trees (same as Dominator) are a different design to those above and look to be in-house made, recall seeing instagram photo's a few years back showing cnc work in progress.
 
Has anyone contacted Ohlins to see if they did supply the forks to Norton and, if so, did they supply yokes with the package?

Glen
When I had my CR converted to handle bars the factory offered to either supply a new top yoke or machine my existing one for handle bars fitment, no mention of ordering in from Ohlins etc, I’d suggest they were made in house, or at least locally.
 
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