Carb spray tube - cut away = stepped
- Thread starter Staytite
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Your answer will probably have to come from within the US (or outside Europe at least) as we were stuffed with the Mk*A versions of the 850.
Based on the parts lists and what Stockie2 says, everything points to cutaway tubes on all 850s.
If you're not running the airbox originally supplied with the bike (either paper filter or black bladder) then the factory settings can only be regarded as a starting point and you can approach the carb tuning knowing that various options are available.
Based on the parts lists and what Stockie2 says, everything points to cutaway tubes on all 850s.
If you're not running the airbox originally supplied with the bike (either paper filter or black bladder) then the factory settings can only be regarded as a starting point and you can approach the carb tuning knowing that various options are available.
Hi 79x100
I am building an 850 from mainly new/NOS parts and have fitted the earlier metal oval airbox with paper filter
together with peashooter silencers. So standard for an early 850.
It would seem from th ereplies that all 850s were fitted with the stepped spray tube. My new Amals have the stepped
spray tube. I just wondered if this was the best and not a "bodge" by Norton at the time to get through the emiision/noise
regulations of the time.
As per my reply (sorry it was short - I was in a rush) to Stockie2 I am interested in fitting what is best from a performance
(not high performance) point of view rather than originality.
I have now read the pdf on Amals on the home page of this site. It would seem that the two stoke spray tube is chamfered
rather than stepped (half being cut away to base) of tube as per that fitted to Commandos. Another little point of interest!
THanks to all
Regards
Staytite
I am building an 850 from mainly new/NOS parts and have fitted the earlier metal oval airbox with paper filter
together with peashooter silencers. So standard for an early 850.
It would seem from th ereplies that all 850s were fitted with the stepped spray tube. My new Amals have the stepped
spray tube. I just wondered if this was the best and not a "bodge" by Norton at the time to get through the emiision/noise
regulations of the time.
As per my reply (sorry it was short - I was in a rush) to Stockie2 I am interested in fitting what is best from a performance
(not high performance) point of view rather than originality.
I have now read the pdf on Amals on the home page of this site. It would seem that the two stoke spray tube is chamfered
rather than stepped (half being cut away to base) of tube as per that fitted to Commandos. Another little point of interest!
THanks to all
Regards
Staytite
Staylite, Chamfered spray tubes are in BSA/Triumph triples. My Feb 74 Commando was in my opinion original in the carbs and had stepped. The air box was the type with the tee tube on the front plate. Now this makes removing the air cleaner a real chore, and probably cuts down on induction roar. Now we like induction roar, don't we. So I fitted my air cleaner with the non tee tube type. However, one downside, heavy rain can let water in and present carb problems.
I could not notice any performance difference, with the change, so the stepped cutaways are still there.
Cheers Richard
I could not notice any performance difference, with the change, so the stepped cutaways are still there.
Cheers Richard
My 850 is a Mk3 and therefore definitely came with cutaway tubes and the long needles. I played around when I fitted the 750 type airbox with flat front plate (and reverse cones without balance pipe) and came to the conclusion that the lower mid-range pick up was crisper with the full-circle tubes.
However, I've convinced myself of all sorts of things over the years and then gone back to what I started with so I'm not really a reliable witness... :roll:
However, I've convinced myself of all sorts of things over the years and then gone back to what I started with so I'm not really a reliable witness... :roll:
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