67 N15CS Build

Chris Johnson said:

Good catch, I was hoping nobody would notice. It was hanging a bit on closing throttle, a quarter turn in on the pilot screws has cleaned it up for the most part. You definitely need to run these from new long enough to make sure they aren’t spewing fluids then get the rings moving.

I didn’t intend to coordinate but a guy needs to accessorize and it kinda works.

Chris

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Yeah I should get some Red Vans shoes to complete my look in the garage.

Have fun roosting with that engine build on your hot rod desert sled. It does sound healthy.

A few first impressions after two rides over to the next community, about 6 miles each:

Still working on the carbs. The problem was slides open too far and pilot circuit excessively rich. I was suspicious of the #30 pilots that came in the carbs but tried anyway. It’s now tuned better but loads up on overrun… smaller pilots coming and I need to check float height.

The suspension is surprisingly close to correct. I really had my doubts about fork spring rates after seeing standard was so much higher than what I’m running in my BSA & Triumph. Considering I’m bigger than the target rider, I opted for one step higher than standard and it works well. I don’t have any complaints with the lightest oil in the forks and shocks at this point.

This bike makes my little Jack Pine T100 seem like an entry level ride. The Norton is much larger, heavier and far more powerful.

My 5 weeks to tune needs to be amended to 5 weeks to strengthen my legs & arms, and to lose a few pounds.

Chris

I’m finally pretty dialed in on carb tuning. I was surprised to see how much the UNI filters change the tuning compared to open carbs. I had to step down to #20 pilots and dropped the needles one notch from center. The 400 mains seem OK for now.

I got out for about 90 minutes today, riding in the local OHV park. Rear suspension seems right on. Front springs might be a little soft, bottoming out a few times (but feel great). I might give the .85 or .90 springs a shot.

The bike liked to get hot and start pinking, particularly in sand. I completely overlooked the fact that I bumped up compression quite a bit and should have set ignition according to Commando specs. Hopefully that will take the edge off.

I only lost one carb nut and almost melted through my fuel line. Not bad for the first real ride.

Chris

Chris Johnson said:

I’m finally pretty dialed in on carb tuning. I was surprised to see how much the UNI filters change the tuning compared to open carbs. I had to step down to #20 pilots and dropped the needles one notch from center. The 400 mains seem OK for now.

I got out for about 90 minutes today, riding in the local OHV park. Rear suspension seems right on. Front springs might be a little soft, bottoming out a few times (but feel great). I might give the .85 or .90 springs a shot.

The bike liked to get hot and start pinking, particularly in sand. I completely overlooked the fact that I bumped up compression quite a bit and should have set ignition according to Commando specs. Hopefully that will take the edge off.

I only lost one carb nut and almost melted through my fuel line. Not bad for the first real ride.

Chris

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Yeah the old 32 degrees of advance spec is a bunch and can cause some detonation.

You can say "pinging" in the USA.

Did you do any hill climbs?

Pinking is easier to say; the double ing is weird to me.

Getting into it this morning I found the crankshaft oil feed seal blown out so I need to pull a shim from the pressure relief valve.

There was more sludge in the primary than I expected for having maybe 50 miles on it, hopefully just new friction plates seating in.

0.90 kg fork springs ordered today… I’ll do it all again next weekend.

No hill climbs this weekend.

Chris

I got about 90 minutes of riding on Saturday and half an hour of tuning runs in today while taking my daughter riding.

As I’m getting more comfortable on it, I’m able to ride faster and can confirm the fork springs are too soft. The .90kg springs are back ordered but scheduled to be in by Friday. This Norton really is fun to ride and I fit so much better than on my T100.

I made an honest effort to tune out the pinking:
-Timed back to 28 degrees, no good.
-New AAU springs, no good.
-Raised needles one notch, no good.
-One step colder plugs, no good.
I finally relented and mixed up a gallon of special sauce: 91 octane + a few ounces of VP octane improver (raises octane by up to 8 points!!) and I think I can ride this thing safely in the desert, in the sand.

I consider this engine to be similar to a mildly tuned Commando so I’ve been looking there for tips. From what I read, even a stone stock Commando doesn’t like the 91 octane I can get here so I’ll probably leave it at that. The last thing I haven’t tried is strobing it to see at what rpm full advance comes in - I had surprising results doing that to my B44 that used to eat pistons.

Chris