67 N15CS Build

So the little badge bulges are filled like mine, I assume. I couldn't complain, my 2 tanks were worth 5x the price of the basket case. Only one person has ever noticed. Will you put a transfer on like this? Cool 60's colors you got going on there!

Oh - I had no battery side cover and waited a while to get one from Walridge, a repop from India. Not bad. The tanks were signed by Tim Bartee of Lake Elsinore - he has been there forever and has a ton of 'On Any Sunday' era photos and memorabilia in his garage. He painted my side cover to match, 30 years after he did the originals in '94. It pays to sign your work, so people from the past can haunt you.

When I first stripped my tank, I was really confused… there was a ton of bondo basically eliminating the bulges. Prior to that I didn’t even realize they were supposed to be there. Ultimately I chose to keep the screw holes filled and go with a Norton script, bulges now exposed.

My tank was in exceptionally good condition until I decided to pressure test it. 10psi is bad. So now I don’t feel bad if I bang it up in the dirt.

Chris

Chris Johnson said:

My carb choice was determined by finding a NOS 1-3/16” 689. Then I held out as long as I could to find a NOS 389, to no avail, and had to buy a new one. The only negative is the two carbs don’t match.

My original monoblocs were pretty well damaged and I didn’t want to do all this work and compromise on carbs.

Also, taper boring the inlets for the larger carbs found a respectable increase in inlet flow without hogging out the narrow part around the valve guide.

Being new/not filled with soot, now was the time to finish the exhaust. For the style I had in mind, either chrome or black would be appropriate. I chromed a Triumph exhaust and it took something like 6 months so I went with ceramic for this (I had them do my B50 exhaust previously). Also I didn’t metal finish the pipes for chrome - all the welds are present and visible. Ceramic isn’t much of a savings over chrome, for comparison. Oh, I want a finish that would last longer than paint.

Chris

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Tapered port match bore in the head intake ports is definitely the way to go for a street head. Makes a difference for those that can tell what a difference feels like. A dyno is not required to tell if a good taper bore works. Tuner experience will tell the tale.

Thermal ceramic is probably good, since the Silver does work on V8 headers. I don't know about black though. I think it might still go grey close to the head at the first bend on a Norton. I never took my P11 headers to a ceramic coater. Month(s) wait times are no fun. I used rattle can ceramic but it never worked for long. What ended up doing was stripping and sanding the headers and coating them with cooking spray. It mostly burns off but leaves behind a thin shellac like protective coat. My steel headers don't rust, but I do have to rub some cooking oil on them a few times a year. Not recommending it, just saying what I did and it works "for me".

I'm looking forward to seeing your bike finished.

Chris Johnson said:

Being new/not filled with soot, now was the time to finish the exhaust. For the style I had in mind, either chrome or black would be appropriate. I chromed a Triumph exhaust and it took something like 6 months so I went with ceramic for this (I had them do my B50 exhaust previously). Also I didn’t metal finish the pipes for chrome - all the welds are present and visible. Ceramic isn’t much of a savings over chrome, for comparison. Oh, I want a finish that would last longer than paint.

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Ohh, so the coating is at the exterior? I was under the impression you wanted to coat the interior, which promises som thermal / thermodynamic advantages to the engine as a whole.

- Knut

Jet-hot is doing the coating. Their marketing suggests internal and external coated, good to 1300 degrees. My main concern is durability beyond spray paint.

Chris

I’m actually winding this project down. Jet-hot said their ETA is Feb 12; I should have the rest of the bike finished and only waiting on exhaust for first start & break-in.

I finished paint today. The Norton script is too small, seems like it’s floating in a sea of purple. Oil tank is painted to match with Atlas crossed flag decal for style.

Yesterday saw the magneto finished, installed & timed. I replaced the original electrolytic condenser with a solid state unit from Brightspark. One bearing was in bad shape, probably from arcing across the race so I replaced both. I replaced a few other wear items and it’s good for another 60 years.

Chris

Chris Johnson said:

I’m actually winding this project down. Jet-hot said their ETA is Feb 12; I should have the rest of the bike finished and only waiting on exhaust for first start & break-in.

I finished paint today. The Norton script is too small, seems like it’s floating in a sea of purple. Oil tank is painted to match with Atlas crossed flag decal for style.

Yesterday saw the magneto finished, installed & timed. I replaced the original electrolytic condenser with a solid state unit from Brightspark. One bearing was in bad shape, probably from arcing across the race so I replaced both. I replaced a few other wear items and it’s good for another 60 years.

Chris

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Thanks for sharing your airflow data in post #11. IMHO, your airflow numbers are impressive, considering that you’re running the full induction system (minus the air cleaner), yet achieving essentially the same airflow as a stock 850 CDO RH10 head fit with only a radius entry at the port - the gold standard in stock 850 CDO performance. I don’t know the exact size of the N15 ports, but given that it’s a smaller engine, I’d expect them to be no larger than the 30mm RH10 ports?

I think the script looks fine, but perhaps I'm biased. I've seen some with larger script, and it doesn't look right, sort of loud. Great work!

WZ507 said:

Thanks for sharing your airflow data in post #11.

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I had to go back to see what I actually posted…

Keep in mind that I’m only looking at change from beginning to end. Flow rate is pretty meaningless since the flow bench isn’t calibrated to anything, but it’s great for quantifying change.

What I did see was that 15% improvement at low lift. The curve goes really flat by about mid-lift, showing how restrictive the ports are. From memory I only saw a marginal increase at the upper half of valve lift. The low lift change was mostly a result of taper boring from 1-1/8 to 1-3/16. By then I already had the new guides in and didnt want to try hogging out around them, plus I wanted to preserve port velocity. I’ll stop there because I’m now beyond the limits of my knowledge.

Curiously, this head flowed very poorly compared to a T150 head I built recently. Apples to oranges I know but still interesting.

Oh yea… test pressure would change things. I was right at the threshold of valve size for choosing 15” or 10” water column for testing (I used 15”).

Chris

Chris Johnson said:

I’m actually winding this project down. Jet-hot said their ETA is Feb 12; I should have the rest of the bike finished and only waiting on exhaust for first start & break-in.

I finished paint today. The Norton script is too small, seems like it’s floating in a sea of purple. Oil tank is painted to match with Atlas crossed flag decal for style.

Yesterday saw the magneto finished, installed & timed. I replaced the original electrolytic condenser with a solid state unit from Brightspark. One bearing was in bad shape, probably from arcing across the race so I replaced both. I replaced a few other wear items and it’s good for another 60 years.

Chris

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When you get time, pictures of both side views would be most appreciated.

A ride report after it's all together and tuned to your liking would be nice as well. End of February ish??

Paint and lettering size looks fine to me. I'm about as far from a Norton restorer as one can get though.