1977 850mk3 Pattern Blackcap Silencer Main Jet Size

acotrel · Dec 31, 2022

worntorn said:
Road bikes that require slow application of the throttle to avoid bogging are a real downer to ride, although some guys will put up with that.
That's the fun of a properly tuned Commando, open the throttle and wham, it hits.

Glen

With my bike the slower use of the throttle is barely perceptible. I just don't whack it open real quick. I any case, you don't usually do that when you are racing. You are too busy being smooth. I don't think I have ever opened the throttle quick enough for the lack of vacuum to cause a gasp. With the small ports, it is pretty impossible, even though I use 6D Mikuni needles, which are the slowest taper. Throttle response is usually pretty poor because of the heavy crank anyway. The slower taper needles improve it.

acotrel · Dec 31, 2022

L.A.B. said:
Two?

Or, use the standard needles and needle jets which should be perfectly adequate.
Could you please try not to think of everything in terms of track racing/riding, for the sake of (nearly) everyone's sanity here?

When you are talking about modifying silencers to get better performance on a road bike - what do you think you are doing ? I suggest that if you achieved the absolute best performance out of your road bike, you would not know you had achieved it.

L.A.B. · Dec 31, 2022

acotrel said:
When you are talking about modifying silencers to get better performance on a road bike - what do you think you are doing ?

The thread title is: "1977 850mk3 Pattern Blackcap Silencer Main Jet Size".

The original question was regarding the correct size main jets for the currently produced Blackcaps from Andover Norton. Not about modifying silencers for better performance.

acotrel said:
With my bike the slower use of the throttle is barely perceptible. I just don't whack it open real quick. I any case, you don't usually do that when you are racing. You are too busy being smooth. I don't think I have ever opened the throttle quick enough for the lack of vacuum to cause a gasp. With the small ports, it is pretty impossible, even though I use 6D Mikuni needles, which are the slowest taper. Throttle response is usually pretty poor because of the heavy crank anyway. The slower taper needles improve it.

There you go again.

L.A.B. · Jan 1, 2023

worntorn said:
Les, did you happen to weigh them?

Glen

Ok, so approximately 3kg/6.6 lbs. each and the peashooters they replaced weigh approximately 2 kg.
Edit.
Correction
Previously, I said the front two-thirds of the silencer had no baffling but it's the tapered section plus a short section of parallel tube that has no baffling, it then has a perforated tube extending back through the parallel section.

baz · Jan 1, 2023

L.A.B. said:
Ok, so approximately 3kg/6.6 lbs. each and the peashooters they replaced weigh approximately 2 kg.

Blimey
And that's for less baffled black caps !!
I wonder what the original black caps weighed ?

EstuaryBoy · Jan 1, 2023

Never mind the width.... feel the quality ;-)

1977 850mk3 Pattern Blackcap Silencer Main Jet Size

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