Norton Exhaust Port Repair

[Dzldanz]

Two more Norton. Exhaust port repairs machined and shipped off to Alberta and British Columbia.

 

[Grandad]

Lovely ...............

 

[CanukNortonNut]

Nice work Dzldanz,,

 

[Dzldanz]

Thank you. It’s a labour of love.

 

[FFFCycles]

So where would I have to ship my head ? What is the cost?

 

[Dan1950]

Thank you. It’s a labour of love.

He did a great job on mine. I was somewhat local and got 1 day turn around.

 

[acotrel]

Basic Commando design flaw ? - Definitely not Japanese.

 

[robs ss]

Basic Commando design flaw ? - Definitely not Japanese.

Want a Japanese design flaw - way bigger?
Hyvo chain on early honda fours!
Primary chain on brit twins is a doddle to change by comparison.
The Honda, with horizontally split crankcases and chain between cylinders 2 & 3 requires complete engine/gearbox disassembly to change the toothed chain. FFS!
S'why there are so many old (K1 to K7) fours still with the "chunka-chunka-chunka" at idle. People avoiding a big job.

Took Kawasaki to come up with the gear-driven clutch

 

[Matchless]

Want a Japanese design flaw - way bigger?
Hyvo chain on early honda fours!
Primary chain on brit twins is a doddle to change by comparison.
The Honda, with horizontally split crankcases and chain between cylinders 2 & 3 requires complete engine/gearbox disassembly to change the toothed chain. FFS!
S'why there are so many old (K1 to K7) fours still with the "chunka-chunka-chunka" at idle. People avoiding a big job.

Took Kawasaki to come up with the gear-driven clutch

The 750 SOHC Honda fours had two simplex roller chains running side by side. It was the later DOHC twin cam 750/900 that had the HyVo inverted tooth chains.

 

[robs ss]

The 750 SOHC Honda fours had two simplex roller chains running side by side. It was the later DOHC twin cam 750/900 that had the HyVo inverted tooth chains.

Yes - my bad - you're correct about the chain type - but the point about the disastrous placement of the primary chain is still relevant!
Cheers

 

[baz]

Yes - my bad - you're correct about the chain type - but the point about the disastrous placement of the primary chain is still relevant!
Cheers

Both early cb750 sohc Honda's I owned had a single simplex cam chain that you can soft link
I changed the primary chain on my fj1200 when it'd racked the miles up simply because I couldn't stand the clatter
That's a complete strip down to replace

 

[robs ss]

Both early cb750 sohc Honda's I owned had a single simplex cam chain that you can soft link
I changed the primary chain on my fj1200 when it'd racked the miles up simply because I couldn't stand the clatter
That's a complete strip down to replace

Didn't mention cam chain

 

[baz]

Didn't mention cam chain

Oops sorry
Just re read
But as said my fj had around 60k miles on it
And the rattle at idle even with the carbs carefully balanced was too much for me
So it was a crank out job to wrap the new primary chain chain around it
Dead quiet after that

 

[Mart UK]

Even with a soft link cam chain, on the SOHC CB750Ks the engine has to come out. Can't even remover the head cover, without removing the engine.

 

[baz]

Even with a soft link cam chain, on the SOHC CB750Ks the engine has to come out. Can't even remover the head cover, without removing the engine.

You can if you cut the two outer frame top tubes
Then weld them back after
Or dogleg the tubes like the drag racer boys used to do

 

[jseng1]

Why doesn't someone just machine new threads and provide a larger diameter exhaust nut?

 

[Tornado]

Why doesn't someone just machine new threads and provide a larger diameter exhaust nut?

Thats what my 850 had done by a DPO....the oversized port and left hand thread meant the nut was basically unobtanium. When it started coming loose, needing frequent torque ups, the nut fins started to get damaged. DzlDan's repair sorted it all out for me.

 

[Tornado]

So where would I have to ship my head ? What is the cost?

Location is outside Ottawa, Ontario.
Cost was very favourable when my head was done some years ago.
Website with a phone number:

precisioncycle.ca

 

[franko]

"Why doesn't someone just machine new threads and provide a larger diameter exhaust nut?"

If you look in the Norton News magazines from the 80s, Stoltz(sp) offered this in stainless steel. He also had the one piece rocker shaft covers in stainless for sale.

 

[B+Bogus]

Why doesn't someone just machine new threads and provide a larger diameter exhaust nut?

My machinist used to do this for the Lancashire Constabulary bikes back in the day.
Nowadays he makes a bronze insert to return to spec.
I think the real villain of the piece is balanced exhaust systems and shorter thread engagement.
I've never seen an earlier 750 head requiring remedial work, and conversely, every 850 head I've had has needed to be repaired