Bonneville America Forums Forums Technical Forums Performance Mods rookie questions

When using the jetting calc. 42 piolet jets are stock? Both snorkels are referring to the two in the factory airbox?

also looked in the tech vault but can't find a "how to" on jetting/shimming. Any help?

120 mains and 42 pilots are stock in our bikes.

Snorkels-I don't know about that one-I never figured that out-so good question.

This website shows how to jet and shim our carbs (amongst other things). Also has the jet calculator. It's stickied in the perfomance mod section also.

http://www.dinqua.com/

The snorkel is the rubber part coming out of the air box lid where the filter is. You can just grab it and pull it out. The other snorkels are inside the air box but only on the oldr bikes around 02 and 03.

Thanks for answering those but now I have more questions. To shim or not to shim, how do I know if its needed. what is the benefit of non factory carb needles. Do I need the "D" tool for 03 Speedmaster?

Some like TBS needles, some like Thruxton needles, and some like stock. I seem to have had best results with the stock needles and I did try the YBS needles but went back to stock.

Shim if you have a mid range flat spot, seems in most cases not needed.

Not sure what they used in 03 but my guess is the screw has the D head on it, my 04 did.

What is the reasoning/benefit behind the different needles?

The taper and lengths are different effecting fuel delivery.

05 speedmaster. bought the tool. drilled out the hole, and found out it was a regular flat head. d tool for sale.

New questions. I did some mods and rejetted using the calculator to find the correct size. The mods went without a hitch and was amazingly less involved than I imagined. I took a four day trip through the finger lakes in NY and was amazed at the drop in MPG. I went from a 120 main jet to 125 and the distance on one tank (reserve not included) went from about 180 to 130 miles. I was going to get the freak and would need to rejet again but will I be killing the mileage again.

I run a 155 main and 48 pilot and get between 120 and 150 miles before reserve depending how I am driving and the load on the bike. Oh and I have the pods on my bike too with open exhaust.

Will the freak in any way help the mileage?

That's a big drop in mileage for a small change in jet size, were there other contributing factors (i.e. windshield, luggage..)?

I had some luggage but I pack light. An additional say 15 lbs in luggage is generous. all in a backpack and camelback. not saddlebags

Oh, and I did add 1 shim to the needles when working on the carbs.

In nearly 50,000 miles i have never gotten better than 160 miles to reserve, and that was only once. 130 miles is closer to my average.

When I was running stock I got about 45 mpg. Then when I did all my mods and took the windshield off I get 35 mpg now. You should expect some change in mileage because you're pushing more fuel in.

And here's a thread about mpg after rejetting from before.

http://www.bonnevilleamerica.com/forums/...true#Post384833

I've always averaged 52 mpg's. Don't know why, I've changed a lot, but the reserve switch is like clockwork. We're talkin bone stock (sewing machine) to freak kit 2 baffles removed rejetted, same mileage. I've always drove it like I stole it too.

Dang, Aaron!! Green Bean sure is good to you on the mpg's then.

It does amaze me how much different mileage everyone gets. My bike runs great and tricked out with a number of dyno runs. Most of the time I ride around town and consistently get 36-40 mpg. 40 would be mostly highway.

I run 89 octane, and I've used a 17t, 18t, and now a 19t which I think the 19 might drop the MPG's a little.

Just wanted to mention that my 07 TBA had 120 mains, but 40 pilots. I gutted the pipes and rejetted to 132 mains and 45 pilots, which took care of any popping.

It really should be reiterated that if you gut pipes or have less restrictive pipes (reduced back pressure) it is normal to have some decel popping. Eliminating all popping means you've probably overcompensated by adding excess fuel and are running richer than you should be.