Norton Exhaust Port Repair
- Thread starter Dzldanz
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Nice work Dzldanz,,
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He did a great job on mine. I was somewhat local and got 1 day turn around.
robs ss
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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
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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
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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
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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
baz
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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
baz
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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
Tornado
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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.
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Tornado
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Location is outside Ottawa, Ontario.
Cost was very favourable when my head was done some years ago.
Website with a phone number:
"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.
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.
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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
