Main Jet sizing

[Aztec Warrior]

Is there a benchmark main jet size for an 1105cc engine?
Open pipe, pod filters, standard ignition/coils. 122.5 mains currently fitted.
Seems to be too rich.
Nice to know to get it right first time, else I'll end up buying a pile of jets that wont get used.

Cheers

[Pigford]

What carbs

[chrisu]

also what pilot jets ?

[Aztec Warrior]

What carbs

Standard VM28ss.
Idle is the most pronounced for richness, which may be acceptable. Rest of rev range is silky smooth. I will try a 'plug chop' test. Air screws at 1 1/8 turns out. No voltage drop at the coils. Standard pick-up ignition, but it's not a fat blue spark like my Bullet. Will start first kick most times, hot/cold, but can flood swiftly, especially hot. Feels like more compression too. This is a beefed up lump for sure..

Not noted the pilot jet size. Sure its only had the mains upped.

[Pigford]

Dyna S, coils & leads are a worthwhile upgrade

[Aztec Warrior]

Dyna S, coils & leads are a worthwhile upgrade

Especially in the wet I take? I mentioned this elsewhere. Only £163 to find out. But you may be right, a slightly weak spark may be causing the wet weather woe's.

[Al]

If it floods easily as you say that could lead to the richness you describe.
With pod filters / aftermarket exhaust/ possible over bore i would suggest a raise in jet size not lower.
Maybe something is masking the true situation.
What groove is the needle clip in?
What is the most likely cause of flooding; float needles and seats???
Fuel height set incorrectly?
I have a bunch of new mains you could have but i think they are all larger than you are currently using!

AL

[Aztec Warrior]

If it floods easily as you say that could lead to the richness you describe.
With pod filters / aftermarket exhaust/ possible over bore i would suggest a raise in jet size not lower.
Maybe something is masking the true situation.
What groove is the needle clip in?
What is the most likely cause of flooding; float needles and seats???
Fuel height set incorrectly?
I have a bunch of new mains you could have but i think they are all larger than you are currently using!

AL

Shall 'press on'......Nothing is ever straightforward when multiplied by 4 (compared to a Bullet)....

[Pigford]

Weak spark will also give signs similar to a rich mixture - sooty plugs

[hanskloss]

Hi, not exactly your setup but might help:
1075 wisecos, dyna S + dyna coils, one off open 4in 4 exhaust, VM28 carbs, airbox with K&N filter, 120 mains, 20 pilots - mixture is spon on.
After fitting the wisecos tried 115 mains and 17,5 pilots and while bike run OK plugs were whitish throughout the revs range, it also took a while to warm up before I could close the choke lever.

[Aztec Warrior]

Weak spark will also give signs similar to a rich mixture - sooty plugs

Will be checking this again too. They are sooty, so must do a fast run/stop/plug chop test first. Too much idling/warming up will also mean false readings.
I also have to compare the spark, with/without the ballast resistor. It was by-passed before me, but I hooked it back up recently, and appears to work ok.

[Aztec Warrior]

Hi, not exactly your setup but might help:
1075 wisecos, dyna S + dyna coils, one off open 4in 4 exhaust, VM28 carbs, airbox with K&N filter, 120 mains, 20 pilots - mixture is spon on.
After fitting the wisecos tried 115 mains and 17,5 pilots and while bike run OK plugs were whitish throughout the revs range, it also took a while to warm up before I could close the choke lever.

Nicely set up by the sounds. I'll be looking closely at all these pointers here for sure.

A member from Poland. Are you the only one here I wonder! I'm impressed with your country, your people and your history, with three visits in 2013. Will be in touch.

[Aztec Warrior]

Checked the float bowls last week, all clean.
Set the floats at 25mm, as per Clymer's start point. All needed it.
All jets are clean and clear.
Needle jets/needles all ok.
Pilots are 15
Mains 122.5

Used the ST for commuting this week, and it has started, on the button, every day. Full choke needed but can close it after a minute or two.
All speeds this week seemed ok. 0-60, 60-80/90, steady as a rock (and the cars were still passing me on the M2 this week?).
No glitches at those speeds, but still way too rich. Tickover is fine but the smell is all wrong.
Finally, it started 'faltering' coming home yesterday, like bogging down. Made it home, still running at tickover, but that exhaust smell is too strong. Plugs were giving up I think. Thick black.
A few hours later, with the air filters removed, a static test made no improvement. Finito.
Some 120 jets are on order.
If still no joy, I'll need 117.5 x 4. If you have spares/swaps, it would save another £12.
Cheers

[Pigford]

Did you remove all the jets? Make sure they're in properly.

[Aztec Warrior]

Did you remove all the jets? Make sure they're in properly.

Affirmative.
Will need some gaskets really. The odd 'ooze' on a fingertip here and there. All inlets rubbers/clips/vacuum bungs/breather pipes/overflow pipes sound.
Petrol is clean and crystal clear, which is surprising given the state of the tank with it's 'failed' sealing job! Bowls all clean.
As mentioned, at speed, ok, but, it finally gave out yesterday. Plugs cant take it I suppose, about 50 miles covered. That exhaust smell is the 'killer'.
Must down jet, Afterall, I'm no where near weak running.

The float chambers have never appeared to overflow at any time, that smell would be obvious, so I assume the float needle jets are doing there job.

I assume too that the Pingel tap is not to blame, as it does flow, like a kitchen tap?

Also, if this is, as suspected, an 1105cc piston kit, how low, mains wise should, I be going?