Plig chop results and odd behavoir

[Snails]

So I'm trying & struggling to set my carb up

So I have a strange boggy part performance wise at 3/4 throttle position



but my mid throttle appears very white (I'll drop that back a clip as I have previously experimented with that and found it ok on the 3rd clip)



Full throttle also appears a little white - so that suggests that the main jet should be increased as well



But how can I have a boggy rich bit in between the needle and main that both appear weak?

Lastly after the last plug chop run - the middle throttle that gave the whitest results when I went to start the engine it would not run properly. It was really chocking with the throttle full open. Anything other than full open would not run. Checked plug colour again at that point and its really sooty. I had to take the air filter off to get it going. Normally it starts fine though - and had done before I started doing the runs. Any idea why that might happen?


25phbl on 175 SR kit
43 idle
30 slide
2 turns out for air fuel
d22 needle (2nd clip)
105 main
5 grm float

[YAMLAM]

WHAT ATOMISER YOU USING ?

[Adam_Winstone]

I had this recently with a restrictive exhaust (small tailpipe) that couldn't get rid of the heat fast enough, resulting in the top end running too hot, regardless of how I tried to jet or time around the issue. This was driving me mad as my plug was also white/light grey on rich jetting so I swapped to a freer flowing exhaust and the plug went from white to black, for no other changes!

This change then allowed me to revise the jetting back to what felt right and the plug colour changed to reflect that.

Adam

[Snails]

WHAT ATOMISER YOU USING ?

Aq264

[Snails]

I had this recently with a restrictive exhaust (small tailpipe) that couldn't get rid of the heat fast enough, resulting in the top end running too hot, regardless of how I tried to jet or time around the issue. This was driving me mad as my plug was also white/light grey on rich jetting so I swapped to a freer flowing exhaust and the plug went from white to black, for no other changes!

This change then allowed me to revise the jetting back to what felt right and the plug colour changed to reflect that.

Adam

That would be very annoying but thanks for the advise. What exhaust was it that you had before and after out of interest

[Adam_Winstone]

AF clubman changed for Cam Lam / Tino Ancillotti clubman.

[corrado]

Is that slide correct? Out of the box they come with a 40, which is leaner plus an AQ266 which is richer. Ball park mid range is D22, 50 pilot, AQ266 & 40 slide. Obviously they're all different but a good, [generally accepted,] ball park is where to start.

[Snails]

Thanks Adam - I've got Cam Lam Ancillotti copy fitted (the cheaper version) but that does not mean that its not causing the same issue. However I have read within the Scooter Centre set up guide for carbs the exact same description of the issue I have with a suggestion of changing the needle so I will try that first before going down the path of changing the exhaust.

I have tried another needle previously and just found it to be un rideable (boggy) but maybe that was only with a particular idle / main / clip combination - or maybe another a totally different needle / atomiser combination is required. Great, as I think that means that I have another 28 possible combinations to try. Should be just about ready by the end of the summer