Bonneville America Forums Forums Technical Forums Performance Mods Popping on Decel

I put new pipes on & jetted my 06 America this weekend. Did it myself with the help of Dinquas site (He is the Triumph god!!!). I used his jetting calculator & determined I needed to go to 130 main jets. The only mod is AI removed. The pipes are D&D. I took it for a run & when I downshift & decellerate, it pops some. Can this damage my engine? I don't want to do this job again. I can live with the annoying pop.

Some popping is normal. Too much means its too lean. Did you back out screws?

as lonzo said, back your pilot screws out to about 3 turns. If you have to go to 4 turns out, then up your pilots and start with the screws in to about 1/2 turn out.
You can also get a bit of pop relief by balancing your carbs too.

Thanks guys.I will need to get a D-Tool. Pat I do have to say I got a bit confused on the site when it said if you have an 04 BA or SM you need to use a d-tool. Is it unusual for an 06 BA to have the d-tool adjustment on the carbs. Can the popping damage anything?

No D tool is 04 on up as I remember. You can put slotted screws or finger type screws in. I got a slotted set from a friend that owns a custom HD shop, he gave me some used ones. I took the D screws out of my bike with small needle nose when I had my carbs off.(Wendys bike got the used screws) Then cut slots in the D screw with my Dremel tool and cutting disc and put them back in, works like a charm.

Hi Steve,

My .02 .....

Here's a couple links talking about how some fabricated their own D-Tool. There are plenty of other ideas out there, ie. certain ball point pen (empty of course) refills work.

D-Tool
D-Tool
D-Tool

As Dog said, once the screws are out you can slot them, but if this is the route you take be very careful. Saw the soft brass too deep and they may break next time you're messing with them while in the carb and become a pain in the tuckus to remove again.

These are a good investment from Brent. They closely resemble our current screws, while the HD screws sold through Bellacorse do not. I've owned both.

The "a$$"umption is your current screws are set to factory spec of about 1.5 turns out. I suggest you first turn them clock-wise until they seat (not tightly!) and count the 1/2 turns to verify this. Then, back them out (counter-clockwise, or "anti-clockwise" as our friends across the pond say) to 2.5 turns. Ride, then continue to adjust .25 to .5 turns further until decel popping is mitigated. IMHO just a little "occasional" popping is a cool thing.

Be careful when removing the screws. Each have a teeny-weeny (sp?) rubber 0-ring, spring, and washer on each. Place a rag under the bowl during removal. Check the screw for the 3 little pieces on removal. If one is missing (usually the washer), tap the entrance point lightly with a hard object expecting the missing piece(s) to fall onto the rag.

Have fun, because it is just that "fun". Much better than watching some lame show like "American Idol" on T.V.

Regards,

Tom

Before I forget .....

I meant the o-ring sometimes get stuck in the carb-body, not the washer.

Also, you may want to consider posting a WTB ad in the classified section for the tool itself. Someone who changed carbs or bought the nurled screws, may want to sell their D-Tool.

Who knows someone may send you the tool for 2-way postage if you ask nicely? (I gave my old one away sometime back)

Regards,

Tom

Sluft, Where are you located in CT? I have a D-tool that you can use depending how far away you are.

upping the mains is upping the fuel when the throttle is cracked wide open. Popping at decel is more in the idle circuit. It is caused by a lean condition at that throttle position. There are a couple things that usually contribute to this.

First, is the easiest and cheapest- did you use high temp sealant when you put the D&D's on? You may have cooler atmospheric elements re-entering the head (or in layman's terms- you got a leak in the exhaust introducing fresh air back into the cylinder- it's the same principle as the AI system that came on the bike).

Second- the pilot jet needs to be upped one size. Try a set of 45's.

Remember, all these jets make up the fuel map, or range. A change in one has a minor affect in all ranges. So upping the pilots to 45's may require you to drop the mains to 125.

Play with the calculator, study the diagrams on what parts do what, and to be friends with the carbs. Jetting gets a little obsessive. If you get a FREAK, the job is much faster and easier. I can rejet in about 20 minutes without removing anything but the bowls on the bike- and it makes more power, too...

Let the tinkering begin!

Thanks fellas, but I ordered a d-tool from Brent after I posted this last night. It seemed Like the easiest thing to do for me. Thanks for all the kind advice. I hope it cures my problem.