Bonneville America Forums Forums Technical Forums Performance Mods BUB Slip-on pipes

Need a bit of advice. Those who have them-what did you use for jetting and needle settings? My plugs look a touch white-not totally but a touch! Thinking I better do a swap but need a suggestion. Thanks

Dinqua's calculater (clicky) gives 130 mains at sea level with Bubs assuming everything else is bone stock.

I'd go up to the next main jet you can easily get. If you have stock 120s, try 125s. If you running 125s, try 128 or 130. My dealer insists that it is better to be a bit on the small side than too big. Since they got their dyno, they have been dropping main jet sizes and seeing better results.

Thanks, guys. I'm all stock so one more question. What mains and pilots do I ahve from the factory. manual is no help.
King

The bike comes stock with 120 main and 42 pilot jets. By adding the Bubs, which are less restrictive than stock, you need to go up on the mains. I would try 125 first and leave the 42 pilots. That's what I'm running right now and the Specialty Spares are almost the same as the Bubs.

I've got the Bub slash cuts, and I dig 'em.
45 pilots, wrong thumbscrews, 135 mains,
1 shim on stock needles, UNI, no snork. No AI.
See the NH Dyno results, and "Uncle Charlie's Dyno Run"
on youtube.com. 65.34RWHP, 49.83ft/lbs torque.
Any questions?
Uncle Charlie

Ok. Here's how it played out. Bike had 120 mains and 40 pilots from the factory. Went to 128 mains, 42 pilots, and one shim (thanks BelleCorse0 and the bike runs REAL well. Plugs look good so off I go! Hope this will help others.

I have an 07 speedmaster.
bubs, no ai, no top snorkel, oem air box and I have 122 mains and 3 shims.

it runs fantastic but I am actually changing it to 125s and will see if I need to remove one shim.
my only issue is WOT is a bit lean (seat of pants dyno).

130 mains with one shim made things sputter at about 1/4 throttle. was dynoed at that point and still got 53 FPs of tourque.