Jetting

[Micky67keane]

I've not long since changed my exhaust from a BGM v2 to an Avanti ST.
Ive got a RT195 with 60 x 110 rod running a 28mm PHBH.
Scoot seems to be running and pulling ok but when I checked my plug it was very wet/oily.
My jetting is:-
30 SLIDE
55 pilot
AV 266
X 7 1.5 clip from top
118 main
Would I be right in saying a change to AV 266 with X13 needle would lean it up?
Any suggestions gratefully taken...
Cheers

[Rich Oswald]

Did you really mean to write 30 slide? That is a massively rich slide. 55 pilot is a bit over the top too imo.

[Micky67keane]

Yes,the slide was a 40 which was modified by the guy who built my engine.Was unsure if it was leaner or not,looks like I need to order a 40 slide..
Thanks for the info

[Rich Oswald]

Yes,the slide was a 40 which was modified by the guy who built my engine.Was unsure if it was leaner or not,looks like I need to order a 40 slide..
Thanks for the info

Tbh, i'd even consider a 45 slide.

[Storkfoot]

Was it running well with the bgm Clubman fitted? If so and if it was jetted correctly then, it is likely that you would need to richer your jetting for an Avanti.

If I was you, I’d mark up my throttle grip 1/8, 1/4 etc and then try and identify where on the throttle progression it is running overly rich, if it all.

Your Slide. By the sounds of it it is stamped 40 but the previous owner has increased the radius on the curve. Is that correct?

If so, the slide you have will be leaner than a 40.

[Micky67keane]

Was it running well with the bgm Clubman fitted? If so and if it was jetted correctly then, it is likely that you would need to richer your jetting for an Avanti.

If I was you, I’d mark up my throttle grip 1/8, 1/4 etc and then try and identify where on the throttle progression it is running overly rich, if it all.

Your Slide. By the sounds of it it is stamped 40 but the previous owner has increased the radius on the curve. Is that correct?

If so, the slide you have will be leaner than a 40.

Everything you say above is correct,it was ok on the BGM,the slide radius has been ground away which I thought would lean up the mixture but my plug is very oily.Have ordered a 40 slide then gona have a look what thats like.Thanks for the reply

[hullygully]

my mates running a RT195, super tourer, 28mm Delly open mouthed, needle - X13p2, fuel jet - 300,
pilot - 57, m/jet - 122, slide - 40, atomiser - AS266, choke - 70,
he holed his piston with a 50

[Storkfoot]

Was it running well with the bgm Clubman fitted? If so and if it was jetted correctly then, it is likely that you would need to richer your jetting for an Avanti.

If I was you, I’d mark up my throttle grip 1/8, 1/4 etc and then try and identify where on the throttle progression it is running overly rich, if it all.

Your Slide. By the sounds of it it is stamped 40 but the previous owner has increased the radius on the curve. Is that correct?

If so, the slide you have will be leaner than a 40.

Everything you say above is correct,it was ok on the BGM,the slide radius has been ground away which I thought would lean up the mixture but my plug is very oily.Have ordered a 40 slide then gona have a look what thats like.Thanks for the reply

Good luck. Be open minded about the exhaust. You may well conclude that the bgm is better suited to your kit in terms of general tractability, if not top end speed.

[Adam_Winstone]

Not sure if the responses above did pick up on it, which I may have missed, but swapping to an X13 will richen it, rather than 'lean it up' compared to the X7 (if using the same AV266 atomiser).

If you have a look at an X needle chart (available online) you will see that they are both the same body diameter (2.5mm) and tip diameter (1.8mm), with the only difference being taper length. The X13 has a 22mm taper, whereas the X7 is 20mm, meaning that the longer taper of the X13 lifts out of the atomiser 2mm earlier, making it richer faster.

Whilst on the body and tip, both should be exactly the same. It's only the taper length that differs and influences the rate of richer faster.