Removing peashooter inserts?

My Mk2 came with these inserts..



If I removed them, I presume the carb settings need to be adjusted?

Bonzo said:

If I removed them, I presume the carb settings need to be adjusted?

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Which main jets are in there now?
Needles may need to be raised a notch.

L.A.B. said:

Which main jets are in there now?
Needles may need to be raised a notch.

Click to expand...

260.

Without looking, I can't remember which notch the clips are on.

Bonzo said:

260.

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260 is the normal 850 peashooter size.
There's no data available for the 850 exhaust with 'mutes' as far as I know, only what's stated in the manual for the 750 which is one size smaller main jet (210 instead of 220) and the needle clip in the top needle groove (weakest) position.

Thanks Les.

To be honest, I don't think they need to sound any louder, but was curious. I guess I'll just try them and see

..and I take it by 'normal 850 peashooter', you mean pipes without the mute?

Bonzo said:

..and I take it by 'normal 850 peashooter', you mean pipes without the mute?

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Yes. The manual and Amal data for 850 Mk1 and Mk2 (not Mk2A) is 260.

According to the 850 Mk2/2A parts supplement, the Mk2 had the 064609 reduced outlet (1 1/8"?) peashooters but with no apparent change to the main jet size as mentioned (Mk2 932/35 and 932/36 spec. carbs) and could be why the mutes have been fitted.

The actual 064609 type peashooters are no longer available (from AN at least).

Main jets are usually too rich, so they grant a temperature reprieve. at full throttle The most important are the needles and needle jets - they are in use as you accelerate and change up through the gears., If the exhaust is too restrictive, the cam might not work properly, so you are down on power, but comply with noise rules - your choice. For normal suburban use, the main jet sizes are pretty much irrelevant, but on a freeway where the throttle is held wide open for long periods, the main jets are still better if on the rich side.
If you have reduuced the restriction of the exhaust, the jetting will usually lean-off slightly. If you ever get the cough when you are changing up theough the gears while accelerating - that is the sighn the jetting is too lean. Do not continue to ride the bike, but richen the jetting by raising the needles.