Knocking / rattling inside primary drive case + backfire

Felt seal in situ:

Knocking / rattling inside primary drive case + backfire



Also, I’ve managed to align the stator perfectly. Even gap of 10thou all round. I found that it was all down to very careful shimming of the centre stud. Just one thin shim was the difference between 8 and 10 thou.
 
M-Hawk said:
Felt seal in situ:

View attachment 104052


Also, I’ve managed to align the stator perfectly. Even gap of 10thou all round. I found that it was all down to very careful shimming of the centre stud. Just one thin shim was the difference between 8 and 10 thou.
Click to expand...
Just to be sure
First and foremost the inner chaincase has to be shimmed by bolting tight to the crankcase
Then adding shims to the centre stud until the chaincase is mounted perfectly
The alternator clearance is secondary to this
 
M-Hawk said:
Felt seal in situ:

View attachment 104052


Also, I’ve managed to align the stator perfectly. Even gap of 10thou all round. I found that it was all down to very careful shimming of the centre stud. Just one thin shim was the difference between 8 and 10 thou.
Click to expand...
Keep in mind that there is a reason to install the inner chain case with no shims and ensuring that the inner chain case does not interfere with the swingarm, and then measuring the shims required. Once the outer primary cover is on and tightened if the shims don't stop it, the inner chain case will move towards the cradle and may again make the stator out of line. One way to be sure is to put a spacer and nut on the center stud once the inner chain case is on and tighten to see if the inner chain case/stator move.
 
Nice job! I am enjoying this thread (but not your misery!) as I am building up my chaincase now as well. Interesting that AN spot welds 6x where all I've seen are 4x. Getting the felt in puts you in rare company.

I have a habit of using an indelible marker to note Blue Loctite on bolts, shim totals on backside of case and clutch basket directly on the inner chaincase surface. Posterity? Bread crumbs? Battle scars?
 
Thanks for all of your help everyone. Here's the mother of all updates:



3000 rpm is as high as I dare go before I check more of the bike out. No backfire though! I tightened the right side exhaust port, and also used the correct amount of choke.



I'm not out of the woods yet, but good progress nonetheless.

How does it sound to you all? As it should? The rattle and clonk has certainly gone.

EDIT: The primary chain is a bit on the tight side, I'm going to slacken it slightly.
 
Hello. Apologies for the leave of absence. The bike was really driving me nuts, so I stood it up and covered it over for a time...

Anyway, in the last couple of weeks I decided to have another go at it. Here's what's changed:

New battery (good quality 9ah gel type).
New Amal Premier carbs (I was convinced that the bad running was an air leak in worn carb body, so I took the plunge and invested in these).
New spark plugs (again).

So I filled with fresh premium fuel, fitted the battery, fitted the new carbs, new spark plugs and synchronised the throttle cables perfectly. I also checked and adjusted the valve clearances. With this it seemed to run slightly better. I even managed to get it to idle and started trying to tune the idle circuit. But still, it was difficult to start, would hunt and sometimes pop when running and would randomly cut out and then fail to re-start again at all, no matter how hard I tried.

I then moved on to checking and adjusting timing. The bike has Wassell electronic ignition fitted so I downloaded the instructions from here: https://burtonbikebits.net/bbb/wp-content/uploads/2019/03/WW61495.pdf.

Here's what I did:

* First I double checked the timing scale accuracy using the Andover timing scale checking tool. All good. While I had the primary case off I also re-checked my rotor/stator clearances - also good. Primary case then went back on.
* Next, to find compression TDC I used a borescope to find the max piston height and then looked at the valves (closed). I then noted which of the two timing marks on the rotor were near to the timing scale (it was the one with the degree marks next to it).
* I then rotated the engine to come around to 31degrees on the scale.
* When I looked at the Wassell magnetic rotor in the place where the points would normally be it's groove was pointing straight up. I was expecting this to be horizontal, in line with the Norton logo on the casing.
* So I removed the Wassell rotor and stator plate and re-aligned them with each other in line with the Norton logo. The stator plate has two lines: A for Anti-clockwise and C for Clockwise. I aligned the A line as this is the correct choice for the Commando.
* Finally, I double checked my carb settings. Pilot screw 1.5 turns out. Throttle stop screws flush with the body. I had already adjusted the throttle cables to achieve good synchronisation.

Next step was to start the bike and fine-tune the timing with the strobe gun. With high hopes, I tried starting the bike only to find it's now worse than ever. All I managed to get was a couple of loud bangs out of the exhaust. This is maybe after 30-50 kicks.

I've tried a few different starting procedures. The one I found works best is no choke (it's warm here at the moment), tickle the carbs until the first sign of fuel. Ignition on, kick.

So after a few days of enjoying working on the bike, I still don't have something that I can ride. Any ideas? Did I miss something?

As always, your input and support is much appreciated.

PS
When I pulled the (new) spark plugs to make it easier to set the timing I found they were pretty sooty.
 
Last edited:
You've been quite thorough and detailed in your observations. Have you confirmed fuel flow and levels within the float bowls? The premiers, the rec is to use actual fluid level rather than a measurement of float height. I used clear hose plugged into an old plastic bowl drain plug, held hose against carb to watch where fuel level came to. Should be very close to bowl/body sealing flange (check amal website for exact rec of level) adjust float accordingly.

Have you got good compression?
Are you operating choke correct direction?
Did you test new carbs for blockages in idle circuit? Swarf can be present out the box. Gotta see a good spray out the two tiny holes in carb throat when applying aerosol wd40 etc to fuel pickup port underside of carb, other passages blocked. Also remove, blow through the nw pilot jets to get good spray out the little holes in the jet.

After failed starts, are plugs wet/smelling of fuel or dry? Might identify flooded or starved condition.
Try some starter fluid into intakes to see if helps get pops.

Also, my wassel ei manual states to set timing 28/31 btdc. Assuming that the euro convention, it means 28 to 31 degrees. When I push mine to 31 ish, got a few kick backs and more difficult starts, so now I'm at 29 or 30. Starting never kicks back and 9 out of 10 starts are one kick, even cold, tickled, no chokes installed. Seems to like throttle held open upto 1/8 turn on grip, hot or cold.
 
Last edited:
M-Hawk said:
Hello. Apologies for the leave of absence. The bike was really driving me nuts, so I stood it up and covered it over for a time...

Anyway, in the last couple of weeks I decided to have another go at it. Here's what's changed:

New battery (good quality 9ah gel type).
New Amal Premier carbs (I was convinced that the bad running was an air leak in worn carb body, so I took the plunge and invested in these).
New spark plugs (again).

So I filled with fresh premium fuel, fitted the battery, fitted the new carbs, new spark plugs and synchronised the throttle cables perfectly. I also checked and adjusted the valve clearances. With this it seemed to run slightly better. I even managed to get it to idle and started trying to tune the idle circuit. But still, it was difficult to start, would hunt and sometimes pop when running and would randomly cut out and then fail to re-start again at all, no matter how hard I tried.

I then moved on to checking and adjusting timing. The bike has Wassell electronic ignition fitted so I downloaded the instructions from here: https://burtonbikebits.net/bbb/wp-content/uploads/2019/03/WW61495.pdf.

Here's what I did:

* First I double checked the timing scale accuracy using the Andover timing scale checking tool. All good. While I had the primary case off I also re-checked my rotor/stator clearances - also good. Primary case then went back on.
* Next, to find compression TDC I used a borescope to find the max piston height and then looked at the valves (closed). I then noted which of the two timing marks on the rotor were near to the timing scale (it was the one with the degree marks next to it).
* I then rotated the engine to come around to 31degrees on the scale.
* When I looked at the Wassell magnetic rotor in the place where the points would normally be it's groove was pointing straight up. I was expecting this to be horizontal, in line with the Norton logo on the casing.
* So I removed the Wassell rotor and stator plate and re-aligned them with each other in line with the Norton logo. The stator plate has two lines: A for Anti-clockwise and C for Clockwise. I aligned the A line as this is the correct choice for the Commando.
* Finally, I double checked my carb settings. Pilot screw 1.5 turns out. Throttle stop screws flush with the body. I had already adjusted the throttle cables to achieve good synchronisation.

Next step was to start the bike and fine-tune the timing with the strobe gun. With high hopes, I tried starting the bike only to find it's now worse than ever. All I managed to get was a couple of loud bangs out of the exhaust. This is maybe after 30-50 kicks.

I've tried a few different starting procedures. The one I found works best is no choke (it's warm here at the moment), tickle the carbs until the first sign of fuel. Ignition on, kick.

So after a few days of enjoying working on the bike, I still don't have something that I can ride. Any ideas? Did I miss something?

As always, your input and support is much appreciated.

PS
When I pulled the (new) spark plugs to make it easier to set the timing I found they were pretty sooty.
Click to expand...
Not sure with Wassell, but with other electronic ignitions I would say that your static timing is way off. Are you sure you're using the correct rotor mark when doing the static timing (VERY easy mistake to make). It sounds like you had it right and made it wrong this time.
 
Thanks both. There are a few things for me to check there. I’ll remove the carbs and check for blockages.

Not 100% sure I’m using the correct rotor mark for the static timing. I’ll double check it.

Thanks again. I’ll report back in a day or two.
 
M-Hawk said:
...I then noted which of the two timing marks on the rotor were near to the timing scale (it was the one with the degree marks next to it).
Click to expand...

To clarify, are you saying at TDC the apparently correct rotor timing mark was the one off to the left of the timing scale as you seem to be saying the same thing twice?


M-Hawk said:
Next, to find compression TDC I used a borescope to find the max piston height and then looked at the valves (closed).
Click to expand...

That only needs to be approximate as nothing is set at TDC and one cylinder's valves will be closed. It doesn't matter which cylinder as the system is wasted spark.

M-Hawk said:
When I looked at the Wassell magnetic rotor in the place where the points would normally be it's groove was pointing straight up. I was expecting this to be horizontal, in line with the Norton logo on the casing.
.
Next step was to start the bike and fine-tune the timing with the strobe gun...

...All I managed to get was a couple of loud bangs out of the exhaust.
Click to expand...

M-Hawk said:
Not 100% sure I’m using the correct rotor mark for the static timing. I’ll double check it.
Click to expand...


So, to clarify, you rotated the crankshaft backwards (clockwise from TDC in the opposite direction to the normal crank rotation when viewed from the primary side) until the nearest alternator rotor mark (should be to the left) of the timing scale at TDC aligned with 28/31 degrees (BTDC) at which point the Wassell rotor mark should have aligned with 'A' on the Wassell stator but was getting on for 90 camshaft degrees (thus 180 crankshaft degrees) off, however, it apparently ran like that so it must have been set closer to correct before you repositioned the Wassell rotor as it certainly won't start if the timing is now many degrees out.
 

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