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Mugello Jetting query

Posted: Mon Oct 20, 2014 4:40 pm
by TS1-200
186 Mugello, AF Big bore, 25mm dellorto, remote foam filter, jetting as follow
110 Main
50 pilot
50 choke
D22 needle, 2nd clip
AQ264 atomiser
45 slide
starts and runs pretty good, bit boggy lowdown, but plug shows its running weak, I wouldn`t have thought it should be weak, any ideas.

Re: Mugello Jetting query

Posted: Mon Oct 20, 2014 7:36 pm
by Daggs
An 110 main on that frightens me................................

Re: Mugello Jetting query

Posted: Mon Oct 20, 2014 8:35 pm
by TS1-200
Please explain Daggs

Re: Mugello Jetting query

Posted: Mon Oct 20, 2014 8:57 pm
by YAMLAM
theres me thinking main looks too big !!

Re: Mugello Jetting query

Posted: Tue Oct 21, 2014 8:06 am
by Daggs
TS1-200 wrote:Please explain Daggs
I've built and ridden several standard 175 iron barrel conversions using 22mm Jetex carbs/42mm clubman type exhausts. Every one of them has had a main between 120 and 123.
I've never built a Mugello but have built an Imola. That needed a 130 main albeit it was through a 28mm Dellorto.
So i'm thinking your 110 is way low. Particularly as you describe the engine as running lean according to plug colour.
The plug colour is mostly influenced by top gear running rather than tickover or when accelerating through the gears.
The bogginess lowdown could be the pilot jet or possibly the atomiser.

Re: Mugello Jetting query

Posted: Tue Oct 21, 2014 10:20 am
by Muppet
thinkin 110 is bigish for his phbl the 264 is smallish

Re: Mugello Jetting query

Posted: Tue Oct 21, 2014 11:01 am
by Tractorman
I am working on which main jet I need for my set up, which the same as TSI-200's, by doing plug chops. I started at 96 which is recommended by Cambridge and have worked up to 100 which was just on the weak side so I have 102 in and waiting for the wind to drop to test it.

Re: Mugello Jetting query

Posted: Tue Oct 21, 2014 3:32 pm
by TS1-200
I had a 70 pilot jet in the shed, popped that in and it has improved it a lot, possibly a bit rich at the bottom end although the bogginess at the bottom is all but gone, have ordered a 60 pilot and a 115 MJ. I think the 45 slide hasn`t helped.

Re: Mugello Jetting query

Posted: Tue Oct 21, 2014 3:40 pm
by drunkmunkey6969
Muppet wrote:thinkin 110 is bigish for his phbl the 264 is smallish
Correct

Re: Mugello Jetting query

Posted: Tue Oct 21, 2014 5:40 pm
by TS1-200
Ok, I'll try a 266 atomiser and stick with the 110, and see how it goes