Things I didn't think I would be doing with my 961

My 2013 CR at only 2400mls is undergoing engine blue printing at the moment, not really because of any single apparent issue, other than noise, vibration and the feeling that things were not quite right.

Started with the primary side, doing all the prerequisite fundamentals... new split gear spring, peg the clutch ring gear... heavier oil (which I don't recommend BTW), checked valves, adjusted timing chain - no noticeable difference.

Digging deeper - found the balance shaft roller bearing toast.

Digging deeper again - found the crankshaft centre main mounting plate not tight, allowing the crank to deflect, resulting in a 6 thou out of true. This is an factory assembly issue that Norton UK are not keen to talk about.

Norton Canada provided new roller bearing, gaskets and paid for the crank to be trued as a goodwill gesture. Norton UK said in no uncertain terms - you are on your own, we don't support individuals undertaking their own work (even out of warranty). I have written directly to Norton UK, they are aware of these issues and to date have not made any comment, or even acknowledged that these issues are "known". They have never had the courtesy to reply to my emails either.

Moving along - I thought I would look at the balance shaft itself, as I had heard these cast/forged ones can be out of spec... well yes indeed - bob weights were mismatch causing a 4 1/2 deg offset - I had to grind one of the weights quite substantially to get the shaft to align with the vertical axis. - Not a big deal, but wondering if this had a part to play in the balance shaft roller bearing failure.

I am re-posting a number of the photos of the early tear-down and some new ones of the balance shaft work.. you might find this interesting to follow.

A note to other Owners - It is clear there are probably some "factory manufacturing issues" on certain bikes, maybe batches of bikes. Yes the out of spec issues I have found seem alarming, BUT in all honesty, these issues may never manifest during the ownership of the bike - we are all told "live with (expect) engine noise and vibration" I chose to dig deep into what is going on inside the engine and although there were some surprises, it can be put right with minimal cost of parts, and a chunk of time. I doubt if the bikes would ever "blow up" as a result of the these issues, just the running may slowly show signs of change. A dealer has no reason to dig this deep if an owner comes and says bike vibrates and makes noise, I guarantee Norton would not sanction it as it is the tip of a slippery slope for them.

There is so much good information on making these bikes run the way they were meant to. Besides a new roller bearing, trued crank, new main bearings, balanced balance shaft, vented primary, I will be installing all the BOSCH sensor upgrades, new BOSCH coils and the special plug wires. The ECU has been flashed with the latest maps. To me this is work I am undertaking is the best investment in being able to enjoy this bike long into the future. After all it was "Hand-built at Donnington Hall" and now "Hand-built" again in Canada..









You can view the previous images of the engine tear down

View post on imgur.com

Good information.

bushman said:

My 2013 CR at only 2400mls is undergoing engine blue printing at the moment, not really because of any single apparent issue, other than noise, vibration and the feeling that things were not quite right.

Started with the primary side, doing all the prerequisite fundamentals... new split gear spring, peg the clutch ring gear... heavier oil (which I don't recommend BTW), checked valves, adjusted timing chain - no noticeable difference.

Digging deeper - found the balance shaft roller bearing toast.

Digging deeper again - found the crankshaft centre main mounting plate not tight, allowing the crank to deflect, resulting in a 6thou out of true. This is an factory assembly issue that Norton UK are not keen to talk about.

Norton Canada provided new roller bearing, gaskets and paid for the crank to be trued as a goodwill gesture. Norton UK said in no uncertain terms - you are on your own, we don't support individuals undertaking their own work (even out of warranty). I have written directly to Norton UK, they are aware of these issues and to date have not made any comment, or even acknowledged that these issues are "known".

Moving along - I thought I would look at the balance shaft itself, as I had heard these cast/forged ones can be out of spec... well yes indeed - bob weights were mismatch causing a 4 1/2 deg offset - I had to grind one of the weights quite substantially to get the shaft to align with the vertical axis. - Not a big deal, but wondering if this had a part to play in the balance shaft roller bearing failure.

I am re-posting a number of the photos of the early tear-down and some new ones of the balance shaft work.. you might find this interesting to follow.

A note to other Owners - It is clear there are probably some "factory manufacturing issues" on certain bikes, maybe batches of bikes. Yes the out of spec issues I have found seem alarming, BUT in all honesty, these issues may never manifest during the ownership of the bike - we are all told "live with (expect) engine noise and vibration" I chose to dig deep into what is going on inside the engine and although there were some surprises, it can be put right with minimal cost of parts, and a chunk of time. I doubt if the bikes would ever "blow up" as a result of the these issues, just the running may slowly show signs of change. A dealer has no reason to dig this deep if an owner comes and says bike vibrates and makes noise, I guarantee Norton would not sanction it as it is the tip of a slippery slope for them.

There is so much good information on making these bikes run the way they were meant to. Besides a new roller bearing, trued crank, new main bearings, balanced balance shaft, vented primary, I will be installing all the BOSCH sensor upgrades, new BOSCH coils and the special plug wires. The ECU has been flashed with the latest maps. To me this is work I am undertaking is the best investment in being able to enjoy this bike long into the future. After all it was "Hand-built at Donnington Hall" and now again in Canada..

You can view the previous images of the engine tear down

View post on imgur.com

Click to expand...

Apologies if it was previously mentioned..... when was the Production Date of your bike?

11/13

Engine 501-0520 - put together by tech #58

I’m a tool and die maker / machinists.
How are you finding center line of the balance shaft to scribe the lines?

How are you checking runout on the crank shaft?

Voodooo said:

I’m a tool and die maker / machinists.
How are you finding center line of the balance shaft to scribe the lines?

Click to expand...

By using the centreline of the keyway - it is on the 45deg line (1st picture), then I used a triangle to scribe the vertical line. I had a machined centre to the aluminum disk that I also used to set up the scribe lines. The disk was then installed on the balance shaft - very tight hammer fit and aligned with the centre line of the keyway.


[QUOTE="How are you checking runout on the crank shaft?[/QUOTE]

It is correctly measured on the centre bearing, with both ends supported on vee blocks - which is the way the machine shop set it up. In my picture I used a vee block at one end and the bearing mount for the centre bearing and took the measurement at the end, so naturally my reading was about double (11 thou) than the actual reading the machine shop got at 6 thou.

I’m NOT a toolmaker or machinist, which is perhaps why I still don’t follow you fully. My questions are:

1. How do you know that the centreline of the woodruff key is also suposed to be the centreline of the balancing lobes?

2. Assuming that are are correct, how do you know exactly where the centre of the balancing lobe is? It appears that you are doing this by ‘eye’. But these are balancing lobes, and their true centreline is surely dictated dynamically, ie where the centre of the rotating mass lies. The shaft is clearly not precisely machined all over, it must therefore be fair to say that the visible centreline will not necessarily match the dynamic centreline exactly, it therefore seems to me that the 4 degree error you’ve found may not be an error at all? Or at the least, it will be within the margin of error when the dynamic centreline for both lobes are taken into account.

3. Alternatively, I could be going down a rabbit hole here...!?

Simple math, no need to find centre of balancing lobe. Engine is 270 deg crank - 90deg between cylinders. The timing gear woodruff key is on one of the 90deg axis. Scribing the 45 deg vertical gives the exact centre line of the balance shaft. Using the roller bearings on vee blocks, the balance shaft should rest at the exact mid point. It did not. By removing weight on the heaviest bob weight the at rest came back to the centre vertical. This is static balancing which is typically good enough.In the sketch drawing you can see where the bob weights are in relation to the keyway.



If you look at this picture of the vertical line in relation to the gear tooth, it is in the correct position on the leading edge at the bottom of the tooth, so my layout is confirmed. If this was not in alignment, then an offset key would have to be made.



Dynamic balancing may be a better option but you would have to add opposing weights and all that and do it on a special rig - not worth it IMHO.

Gotcha. Now it’s clear, even to me, thanks for that.

It will be interesting to see what you think to the bike on a ‘before and after’ comparison basis. That is assuming you can remain objective, not easy when you’ve put such effort in!

When will test day be?

According to others that have done this - it is smoother. My bike always felt like it was fighting itself - between the crank and this I can see why. Yes, I will have a subjective before and after report for sure - a few months away yet though.

The next issue to sort out is the binding exhaust rocker spindles - they were almost seized solid. This might also account for some the excess noise at higher rpm that really precipitated the tear down. This is also a known Norton issue that no one wants to talk about. More on this later.

More on the rockets issue please.

That’s a new one on me...

Bushman is making huge strides here. Norton should be, are no doubt are, following this with interest, I know that I am.
Please keep it coming and yes more on the rocker spindles when you find time.

Getting enough oil in the exhaust rockers ? Oil ways clear in the pushrods/lifters ? Your motor should be smooth as silk when you're done !

I am starting a new thread on the Rocker Arms issue.

A parallel twin with a balance shaft has the potential to be a smooth running engine. A comparable engine would be the 865 air cooled Triumph. Ive ridden one of those and it was nearly as smooth as my rubber mounted Commando at highway speeds. It was much smoother than the Commando at low rpm where the Commandos ISOs are non functioning.

Triumph likes balance shafts so much that they put two of them in the 1200

On the other hand, Ive read that an out of balance balancer such as yours was, will actually amplify vibration. Good on you for finding and correcting the problem.

I recently pulled my 1500 mile 1360cc Vincent engine apart to solve the vibration issue that engine had, so I can relate to the work you are doing. The Vincent was relatively easy, a dynamic crank balance sorted it. Everything else in there was looking good.

Looks like you are in for a much bigger job, but your approach should yield a good result.

Glen

We’ve rebuilt 3 engines. And have a few in line now. Balanced everything. Not only do they run smoother they actually run better. Imagine that one side controls fuel / air and the other controls spark. So its not perfect. Once balancing is complete and everything is perfect, its a way better experience. As is, the bike wont break down or fall apart. But taking it further is well worth it.

I already can anticipate Jims reply once he gets to ride it because Ive been involved and rode three bikes doing the same as jim. —- amazing will be the word of that day. Or maybe incredible.

But don’t get worried if you don’t rebuild. People have been improving manufactures engines for years. Camaros and mustangs for example. Anything can be improved upon. Lets not let this thread get out of control or bash Norton—- And rather learn from it. And if you cant do it yourself then send it to one07 and we’ll do it for you.