Bonneville America Forums Forums Technical Forums Performance Mods Changing Jets without removing the carb

My wife's 2001 Custom Bonneville with D&D pipes has a stumble at 1/8th throttle. This doesn't happen all the time and gets better when warmed up. Is it possible to simply remove the float bowl and clean or change out the pilot jet without removing the carbs? She only has 4,000 miles so I suspect varnish on the jets or it was too small when originally installed.

Thanks in advance,

Huw

Yes, patience is required as the rearmost screws on the left side also hold the idle adjuster. A good fitting right angle screwdriver can be a real blessing; however, don't even attempt this without a screwdriver that fits the jet perfectly...one slip and you're screwed. It would be a great time to replace the phillips heads with allens as well. Not hard to do, just an exercise in patience and using the proper tools.

Have you uncapped and adjusted the pilot screws? That would be first. Probably have to pull the carbs to do that. The newer ones aren't capped. Is this a standard Bonneville? I know on my America I've dropped the bowls a number of times and never pulled the carbs. May want to try some Seafoam or a similar product in the tank.

Thanks so much for the info thus far. I will be changing the phillips with allen heads. The pilot screws are around 5 turns out. I have used Seafoam. Maybe, I need to dump carb bowl and fill it with Seafoam? How much Seafoam in the tank is too much? It would be nice if it is varnish and could be cleaned up. Being a custom 2001, I don't remember the pilot jet size and will not know until I remove it. This may be the best way to clean it. At least it is good to know that it can be done without removing the carbs by being careful and having the right tools.

I'll let the real carb guru's chime in, but if you are running D&D pipes and stock jetting, that probably isn't good. If the screws have never been removed, you will probably have a hard time removing them the first time. Pull the carb away from the intake manifolds, but still attached is pretty easy, I recommend that. Pat (Dinqua) has a great "how to" on his website. Ater you get the allen head screws in place, it can be done with the carbs in place (still tricky). DON'T use blue or other thread lock on the carb screws....

It sounds like you're trying to do all the increased fuel flow to match your increased airflow with the pilot jets. 5 turns out is WAY OUT. You may need to go up on both the main and pilot jets. Try upping the mains a little first (128 or 130). If the pilot screws then have to be more than 3 turns out, up the pilot jets from 42 to 45 which should reduce the screws about 1/2.

SeaFoam is normally about 1 oz. per gallon of gas. Estimate what's in your tank, add and shake, then run the tank out. It will probably start improving on the next regular tankful.

Hi Huw, once you get the screws replaced and after a few times of getting the knack, it becomes easier and faster each time, that's if the needs arise that is.. I've never had to take the carbs off but I've done all the jets and needles several times. Like everything, just practice.

staffo

That was easy. It took all of 10 to 15 minutes to roll the Bonnie out, drain one carb, remove the bowl and main jet. I found the main jet to be 110. This was all I needed to understand why my wife complained about her bike with D&D pipes and AI removed not performing up to snuff. I have ordered a set of 130 mains, a set of 42 pilots, and a set of 45 pilots. I am sure she will run a lot better off idle from these changes starting with 42 pilots and recheck after that.

Nukeranger

Well done

It turns out my wife's Bonnie had 110 Main and 45 Pilot Jets. I swapped out the old 45 Pilots with new ones and installed the 130 Main Jets. I put the Pilot screws back to 2.5 turns out. Ramsound may be right about the Mains needing to be 128 or 130. It will be raining tomorrow, so I will find out the affects within the next couple of days. I will keep you posted for information.