Hesitation, stuttering, misfire - help please (2020)

Not sure you’re quite there yet, I don’t think you were wrong with the 2 ring needles, as MicaelB said above, the needle type is basically determined by the spray tube type:

“The needle needs to be matched to the spray jet. Top of needle has rings, notched spray jet works with 4 rings, straight spray jet works with 2”.
 
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Oh sh*t! but it works! :mad: I didn’t do anything relevant other than that. I really thought I’d cracked it.

OK , if I can work up the enthusiasm then tomorrow I’ll undo what I’ve done and revert to 2 ring needles in the square spray tube and see if it goes back to how it was.
 
OK, I’ll get out on it tomorrow, but what to do if it runs well?........... :rolleyes:
 
Interesting, I've never run a 4 ring in straight tube, so I don't know how it performs.
I did acquire an 850 that had the 2 ring in the notched tube and it ran poorly. 4 ring corrected it.
And yes, they are significantly different.
 
well I have just put the Blackbird back together, but I think I really should tax the Busa and remind myself what I've been missing for the past 7/8 months.

otherwise if the Norton continues to run fine with the incorrect needle and spray jet, I may just leave it as is.
 
I know this is completely off the subject of the thread. You have a bird and a busa. which do you prefer and why?
 
The sculpted spray tubes richen the needle and main jet they are usually used on two strokes. I believe Norton fitted them to Mk11 and Mk111 850 's to reduce the main jet size. My 73 Mk1 had the standard spray tubes fitted from new.
 
OK cliffa, I like the Bird because it was a more accomplished Superbike when it came out, better than the ZZR1100 it set out to beat. Overall it’s not a bad bike.
The Busa set a whole new standard, only surpassed by the ZZR1400 gen2 (I’ve had 2 of them).
On the Blackbird, behind a line of cars, it would be down a couple of gears and see how far past you could get before pulling in.
on the Busa, the same line of cars, it was simply twist open the throttle and power past all of the cars.
For many years it was everything to me, sports tourer, sportsbike, race bike and go to for a thrilling ride.
The Honda goes well, is bland, doesn’t stop, doesn’t handle, but is a nice reminder of how well they used to make a bike.
The Suzuki is now of its time, very powerful, good on fuel, brakes well, handles well. Exactly what the world needed. Until the ZZR came along.

I've had 2 Blackbirds and 5 Hayabusas and had at least one Busa for almost every one of the past 21 years.
 
They changed the spray tubes to a split one to get rid of a flat spot the 73 850 seemed to have.That was what my norton dealer told me back in the day.The needle is longer and has to match. The cutaway is as michael said 3 1/2.That is what I do them to after I sleeve them.Even then with the closer tolerances from sleeving the carbs they run rich for awhile.That is probably why you will be fouling plugs.
 
I just did a set for a customer in ohio.The set I did for him 15 years ago are still ok and he is doing another 74 850 so he will keep in touch .They both had 3 1/2 cutaways and split spray tubes.I am sure the #3 slide is at least part of your problem,at least the carburation side. The electrical I am not sure of.I have points ignition and my problem was partly because I was running resister caps.Very weak spark.Good luck.
 
Not much, I replaced my main bodies with the generic bodies with flat spray tubes but fitted with the 4 ring needles and could not notice a difference. Have subsequently fitted the notched spray tubes and again no difference.
 
I woke up this morning with a humongous headache and no incentive to do anything at all apart from lie down in a darkened room. Next time I get the chance I will get out on the bike and I will carry a spare set of leads so I can choose resisted or not.
 
Landspeedracer said:
OK cliffa, I like the Bird because it was a more accomplished Superbike when it came out, better than the ZZR1100 it set out to beat. Overall it’s not a bad bike.
The Busa set a whole new standard, only surpassed by the ZZR1400 gen2 (I’ve had 2 of them).
On the Blackbird, behind a line of cars, it would be down a couple of gears and see how far past you could get before pulling in.
on the Busa, the same line of cars, it was simply twist open the throttle and power past all of the cars.
For many years it was everything to me, sports tourer, sportsbike, race bike and go to for a thrilling ride.
The Honda goes well, is bland, doesn’t stop, doesn’t handle, but is a nice reminder of how well they used to make a bike.
The Suzuki is now of its time, very powerful, good on fuel, brakes well, handles well. Exactly what the world needed. Until the ZZR came along.

I've had 2 Blackbirds and 5 Hayabusas and had at least one Busa for almost every one of the past 21 years.
Click to expand...
Thanks for sharing Landspeedracer, it's great to hear this sort of real world feedback.
And apologies to others for the diversity of the thread.

Cheers,
cliffa.
 
So I think the length of the needle is due to the type of spray tube you have, however I stand to be corrected. The reason being is not to have the needle hang up at WOT. I spent some time playing around with the carbs on my 750 Combat, I installed the chamfered 2 stroke spray tubes, long needles which had to be dropped 1 notch, got great results. I mean this is not scientific, just the pleasure of fettling and thinking I had made things better. I keep bees, as they say, ask two bee keepers the same question you will get 3 answers.........
 
It is my understanding that the stepped spray tube was introduced by Norton on the late 850s due to the use of the plastic air box and the annular silencers causing a flat spot in acceleration.

If you look, (to quote LAB) you will see that all three parts lists for '73 850, 850 Mk1A and '74 850 Mk2 & 2A only mentions the "928/104" (4 ID ring) needle ("Use with Spray Tube 928/107") and "928/107 Spray Tube".

The only apparent difference is that the Mk1A parts supplement refers to the 1A carbs having 230 main jets and .106 needle jets.

Most, including myself, run the stepped tube and 4 ring needles fine with standard exhausts.
 
Steves said:
So I think the length of the needle is due to the type of spray tube you have, however I stand to be corrected. The reason being is not to have the needle hang up at WOT. I spent some time playing around with the carbs on my 750 Combat, I installed the chamfered 2 stroke spray tubes, long needles which had to be dropped 1 notch, got great results. I mean this is not scientific, just the pleasure of fettling and thinking I had made things better. I keep bees, as they say, ask two bee keepers the same question you will get 3 answers.........
Click to expand...
Got any honey?
 
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