67 N15CS Build
- Thread starter Chris Johnson
- Start date
Chris Johnson
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- Joined
- Mar 2024
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- 47
Just one more conclusion to all this:
Short story is the mid range mixture was too fat.
I sent the magneto off to be magnetized by a well known west coast magneto specialist with explicit instructions to do no more than to remagnetize, for which I was quoted 2-3 days. After checking in a few times, by week 4 I was told it had a stuck armature and had been sent to a third party to disassemble. They never really told me what they were up to but it’s back and they honored a verbal quote for magnetizing. I’m pretty peeved with them.
Prior to that when I removed the magneto to ship off, I found that I didn’t properly install the magneto seal & drive end bearing which allowed the magneto to act as a supplementary crankcase breather, puking oil out of the pick-ups all over the back of the engine (at least now I know why it was messy back there). Surprisingly it ran well above idle with the magneto full of oil.
A clean, rebuilt, remagnetized magneto still didnt correct the low rpm, high load misfire.
Back to jetting - I started working in the other direction to lean it out. Now I’m at #4 slides & lowered the needles to the #2 position. This was a huge improvement and good enough for now. I could probably drop the needle to the last position but it sucks making changes since the seat & tank come off every time.
I also tried to wean the bike off the fancy gas & mixed up a tank of 94.5 octane. Every trail from my house is long & uphill, that gives a steady faint rattle from the top end unless I kept rpms in the upper range. Back to the 95.75 octane.
It’s been a good long weekend. This Norton is so much fun to ride and I finally took the time to set the timing correct in my Goldie making a huge improvement in trail riding that one (now on to suspension… does it ever end?)
Chris
Short story is the mid range mixture was too fat.
I sent the magneto off to be magnetized by a well known west coast magneto specialist with explicit instructions to do no more than to remagnetize, for which I was quoted 2-3 days. After checking in a few times, by week 4 I was told it had a stuck armature and had been sent to a third party to disassemble. They never really told me what they were up to but it’s back and they honored a verbal quote for magnetizing. I’m pretty peeved with them.
Prior to that when I removed the magneto to ship off, I found that I didn’t properly install the magneto seal & drive end bearing which allowed the magneto to act as a supplementary crankcase breather, puking oil out of the pick-ups all over the back of the engine (at least now I know why it was messy back there). Surprisingly it ran well above idle with the magneto full of oil.
A clean, rebuilt, remagnetized magneto still didnt correct the low rpm, high load misfire.
Back to jetting - I started working in the other direction to lean it out. Now I’m at #4 slides & lowered the needles to the #2 position. This was a huge improvement and good enough for now. I could probably drop the needle to the last position but it sucks making changes since the seat & tank come off every time.
I also tried to wean the bike off the fancy gas & mixed up a tank of 94.5 octane. Every trail from my house is long & uphill, that gives a steady faint rattle from the top end unless I kept rpms in the upper range. Back to the 95.75 octane.
It’s been a good long weekend. This Norton is so much fun to ride and I finally took the time to set the timing correct in my Goldie making a huge improvement in trail riding that one (now on to suspension… does it ever end?)
Chris
