Schwany
VIP MEMBER
- Joined
- Apr 22, 2020
- Messages
- 3,776
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.
67 N15CS Build
- Thread starter Chris Johnson
- Start date
Have fun roosting with that engine build on your hot rod desert sled. It does sound healthy.
- Joined
- Mar 3, 2024
- Messages
- 43
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
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
- Joined
- Mar 3, 2024
- Messages
- 43
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
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
Schwany
VIP MEMBER
- Joined
- Apr 22, 2020
- Messages
- 3,776
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?
- Joined
- Mar 3, 2024
- Messages
- 43
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
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
- Joined
- Mar 3, 2024
- Messages
- 43
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
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
Attachments
- Joined
- Mar 3, 2024
- Messages
- 43
More thoughts after another weekend of tuning:
I’ve stepped up to an effective fork spring rate of 0.9kg with the option of 1.0kg if necessary. Right now I’m in line with Racetech’s suggested spring rate. With that, I was still bottoming hard on small jumps & square edge bumps. Last night I plugged & relocated the oil ports in the damper tubes, which gave a good 1/2”-3/4” of rapid compression damping at the end of fork travel. Today I only bottomed hard once off a fast, small jump. I’m calling the suspension done at this point. I can certainly ride faster than what’s safe for me.
Pinking is still a concern, mostly under load at low revs after the engine gets good & hot. I just now noticed it wants more fuel at idle; AI says octane booster may require richer settings. I may also raise the needles another notch to see if that cools things down a bit. Spark plugs show reasonably clean, no real clues there. I’ll probably spice up the fuel mix for next weekend and see how it responds.
The gearbox likes to overshoot to false neutral on the downshifts if I’m not careful.
The carbs like to boil if I shut the bike off hot. I’m learning to work with that…
First low speed get-off today in the sand. I finally got that out of the way.
Chris
I’ve stepped up to an effective fork spring rate of 0.9kg with the option of 1.0kg if necessary. Right now I’m in line with Racetech’s suggested spring rate. With that, I was still bottoming hard on small jumps & square edge bumps. Last night I plugged & relocated the oil ports in the damper tubes, which gave a good 1/2”-3/4” of rapid compression damping at the end of fork travel. Today I only bottomed hard once off a fast, small jump. I’m calling the suspension done at this point. I can certainly ride faster than what’s safe for me.
Pinking is still a concern, mostly under load at low revs after the engine gets good & hot. I just now noticed it wants more fuel at idle; AI says octane booster may require richer settings. I may also raise the needles another notch to see if that cools things down a bit. Spark plugs show reasonably clean, no real clues there. I’ll probably spice up the fuel mix for next weekend and see how it responds.
The gearbox likes to overshoot to false neutral on the downshifts if I’m not careful.
The carbs like to boil if I shut the bike off hot. I’m learning to work with that…
First low speed get-off today in the sand. I finally got that out of the way.
Chris
Schwany
VIP MEMBER
- Joined
- Apr 22, 2020
- Messages
- 3,776
AI is relying on information it scrubs out of multiple possibly accurate information sources. There is still plenty of misinformation out there.
If anything it is probably your JS cam and that exhaust that requires more fuel from those old Amals.
A false neutral on a downshift would be no fun climbing a hill.
Getting off in the sand means the honeymoon is over and it is time to start beating on it. Enjoy the roost.
If anything it is probably your JS cam and that exhaust that requires more fuel from those old Amals.
A false neutral on a downshift would be no fun climbing a hill.
Getting off in the sand means the honeymoon is over and it is time to start beating on it. Enjoy the roost.
Chris,
A few questions, please.
* Which recipe did you use when you modified your damper tubes?
* Coil binding may be a problem when altering internal fork springs. Did you check non-binding for the desired travel when using springs with a 0.9 kp/mm spring rate?
(If they don't bind, did Racetech increase OD of these springs vs. the stock springs?)
* What kind of heat shielding did you install for your carbs?
- Knut
Last edited:
- Joined
- Mar 3, 2024
- Messages
- 43
I plugged the 4 holes with 5/16 UNF x 1/4” set screws, locktited & staked then drilled (2) 1/4” holes just above the taper on the damper.
For all their 2341 series of springs (23.5 OD x 410 long), racetech gives a minimum travel of 170mm, about 2” more than I measured with springs removed. What I did notice is the coil count is the same between their 0.80kg and 1.00kg springs; wire diameter increased by about 0.010” (from memory, don’t quote me), ID reduced to accommodate. I’ve not seen stock springs in real life - my bike had 64-65 teledraulics on when I started all this.
Standard thin spacers on the carbs. What I’m reading is the octane boosters containing MMT do like slightly more fuel. Also I’m suspicious that the air filters have lost some of the oil, giving a bit lower vacuum signal, resulting in a weak mixture. Strange that both cylinders needed about one turn in on the pilots after riding this weekend. My last trick will be a few pulls to check the various carb circuits, waiting on a #3 slide for the 389 & a pair of 420 jets to be prepared.
Chris
For all their 2341 series of springs (23.5 OD x 410 long), racetech gives a minimum travel of 170mm, about 2” more than I measured with springs removed. What I did notice is the coil count is the same between their 0.80kg and 1.00kg springs; wire diameter increased by about 0.010” (from memory, don’t quote me), ID reduced to accommodate. I’ve not seen stock springs in real life - my bike had 64-65 teledraulics on when I started all this.
Standard thin spacers on the carbs. What I’m reading is the octane boosters containing MMT do like slightly more fuel. Also I’m suspicious that the air filters have lost some of the oil, giving a bit lower vacuum signal, resulting in a weak mixture. Strange that both cylinders needed about one turn in on the pilots after riding this weekend. My last trick will be a few pulls to check the various carb circuits, waiting on a #3 slide for the 389 & a pair of 420 jets to be prepared.
Chris
- Joined
- Mar 3, 2024
- Messages
- 43
Schwany
VIP MEMBER
- Joined
- Apr 22, 2020
- Messages
- 3,776
Good luck in the off road event coming up in April and with the carburetor tuning before you get out there. I remember doing rushed final tuning in the parking area the evening before starting 250 mile High Sierra District 36 dual sport rides. Good times were had by all.
- Joined
- Mar 3, 2024
- Messages
- 43
My final, rambling stream of consciousness as I finish this project at the last minute:
In my head this is a really long story so I’ll trim it to the basics. After remembering that I installed used pilot jets, then swapping to new ones, the pilot circuit tuned in nicely. The only other change I made was to raise the needles one notch (richer slide & main jets were both bad moves).
The more I think about it, I believe the detonation is caused by other things and I might try to wean it off the good gas after this weekend. I did make the leap to running VP110 diluted down to 95+.
During tuning this weekend, I found both carbs loose, probably happened while riding the weekend prior. This isn’t new to me as I tend to be cautious about warping the carbs so I end up under tightening them; now properly torqued and loctited.
Toward the end of tuning I found a new oil leak under the magneto - lower mag screw came loose. On repairing this I found the mag chain tension sloppy & all fasteners loose, which I think could advance the timing a few degrees. In this case I used a very soft gasket under the mag that tends to extrude & relax over time, relieving tension on the fasteners. Again, torqued & loctited & timing reset to 28 degrees.
Then as a last FU, the threads at the rocker oil feed connection gave up and I had to repair that with a helicoil.
Do or die, I’m out of time
Instagram link
Chris
In my head this is a really long story so I’ll trim it to the basics. After remembering that I installed used pilot jets, then swapping to new ones, the pilot circuit tuned in nicely. The only other change I made was to raise the needles one notch (richer slide & main jets were both bad moves).
The more I think about it, I believe the detonation is caused by other things and I might try to wean it off the good gas after this weekend. I did make the leap to running VP110 diluted down to 95+.
During tuning this weekend, I found both carbs loose, probably happened while riding the weekend prior. This isn’t new to me as I tend to be cautious about warping the carbs so I end up under tightening them; now properly torqued and loctited.
Toward the end of tuning I found a new oil leak under the magneto - lower mag screw came loose. On repairing this I found the mag chain tension sloppy & all fasteners loose, which I think could advance the timing a few degrees. In this case I used a very soft gasket under the mag that tends to extrude & relax over time, relieving tension on the fasteners. Again, torqued & loctited & timing reset to 28 degrees.
Then as a last FU, the threads at the rocker oil feed connection gave up and I had to repair that with a helicoil.
Do or die, I’m out of time
Instagram link
Chris
