09 Buell Blast running issue

A leaky bowl gasket and torn paper gasket will not cause your issues; been there, done that.

Did you make sure the needle jet was installed correctly?

Have you followed the FSM to check the TPS?

How old is your gas? Old gas or water contamination will cause this.

The LED on the cam sensor (ignition module) doesn't light every single time. Ideally it should, but the on/off signal is so fast, it doesn't always light. You could try using a real timing light; connect it up (battery + & -, and plug wire) and just point it at something. If that light is flashing steady, you know the plug is firing.

If you have a measuring caliper, measure the diameter of the hole in the bottom of the slide. Not the needle hole, the one behind it, the Vacuum Port. If it has been drilled out to 1/8" or larger, you're flooding the motor and need a new slide. It's a common modification on V-Twins, but gives too much fuel for the Blast single.

FSM can be found here:
https://buellmods.com

Carb parts can be found here:
https://cv-performance.com/

Needle Jet orientation:


Vacuum port - A, should be smaller than 1/8":

My M2 had the needle jet in upside down when I bought it. I bought it from a indy Harley shop, and he couldn't figure it out either.

Thanks, Jetlee, for shedding some thoughts here. I really appreciate the link to the cv-performance, I see they have the gaskets I need, awesome. The other link (buellmods) did not work for me, maybe it's on my end. Also, what I forgot to mention, when they dropped off the bike from HD, was that it fired right up and I drove it about 50 ft or so to my parking space, without issue. It rained like crazy that night, and the next day, after it cleared up, I went to take it for a test run. This is when the issues came right back (backfiring through carb and choking when throttle was applied, couldn't drive it a foot without it dying), so maybe you are onto something with the water contamination. The fuel itself is a few months old, pending Harley did not add any themselves during their diagnostic service. I have not checked the throttle position sensor as of now. First, I'm thinking, I have to recharge the battery, then dump the fuel and replace with clean gas...eliminate the obvious....I will feel like such a dumb ass if this is the underlying issue. If it is, then I will proceed with replacing the gaskets and hopefully she will be running like new. Truth be told, I miss riding my motorcycle more than I thought I would. I've exclusively been using it as a daily rider for maybe 6 mos straight or so, and would only use my car due to inclement weather. Now that I am back behind the wheel daily, I truly miss the bike even more; car feels a bit cagey. Thanks so much to everyone for sharing their insight and experience in this regard. I am almost a complete novice when it comes to motorcycle work, except for understanding the principles of combustion, so for me, your help is invaluable and greatly appreciated; I feel like I am learning more and more, and it is quite interesting.

I had Dynamic IP's blocked on BuellMods, I meant to disable that part of the firewall. Try it now.

You may want to pull the cover off and inspect the ignition pickup for water intrusion. It could be that the pickup has been compromised and moisture is causing it to act up. Bring a sharpie with you to mark the position of the module plate BEFORE you pull it. Bring some 91% alcohol to help displace the water and aid in drying out the component.

On a side note, the float bowl should hold enough gas to drive the bike on its own for at least 50ft.

Also, make sure the air bleed ports and the float bowl vent aren't blocked on the carb.... and make sure the accelerator pump is squirting gas when you twist the throttle.

https://www.youtube.com/watch?v=5p8qluBZqhI

Here is a link to how the CV carb processes gas and air. The fun parts starts at about the 4 minute mark.

https://www.youtube.com/watch?v=-B-fLDOBqzo

I made a small aux fuel container for when I had my SV650. On that bike the carbs were under the fuel tank, and you couldnt access them without the tank flipped up or disconnected.

Anyhow, it was an empty plastic (peanut butter) jar. I drilled a hole in the bottom and fit a brass barbed hose fitting, and ran a clear plastic hose from the fitting to the carb. Then screwed a small hook on the end to hold it up while I worked. This way I could tune the carbs and verify that the bike was getting fresh fuel.

David Thomas you have had a ton of help here from very smart people to solve your simple issue. Lots of easy things for you to check and fix. Let us know when you're up and running.

34nineteen said:

and make sure the accelerator pump is squirting gas when you twist the throttle.

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Just pointing out the Blast does not come with an accelerator pump.

jetlee said:

Just pointing out the Blast does not come with an accelerator pump.

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I did not know that. I figured since Harley phased those in after the 1st year the carb was put on the Sportsters, it on all of them.

Thanks for the heads up !!! :up:

Cooter said:

David Thomas you have had a ton of help here from very smart AND HANDSOME people to solve your simple issue.

Click to expand...

fixed it for you

34nineteen said:

I did not know that. I figured since Harley phased those in after the 1st year the carb was put on the Sportsters, it on all of them.

Thanks for the heads up !!! :up:

Click to expand...

No worries, just didn't want him trying to run down that troubleshooting tree. lol

Hey guys, hope everyone had a bountiful Thanksgiving. I just wanted to give an update... Charged up the battery, put in fresh fuel, checked the control ignition module was firing correctly, and still nothing. Starts up, and just chokes out. Jets were clean, and everything was reassembled correctly. Fuel is getting in without issue, there's a spark but she just chokes out over and over. I'm perplexed, and perhaps there's a bigger issue here than the carb.

david thomas said:

Hey guys, hope everyone had a bountiful Thanksgiving. I just wanted to give an update... Charged up the battery, put in fresh fuel, checked the control ignition module was firing correctly, and still nothing. Starts up, and just chokes out. Jets were clean, and everything was reassembled correctly. Fuel is getting in without issue, there's a spark but she just chokes out over and over. I'm perplexed, and perhaps there's a bigger issue here than the carb.

Click to expand...

Get a can of starting fluid and remove the air filter. Start it up, and when it "chokes out" spray some starting fluid into the intake.

If its fuel starvation, the motor should continue to run as you spray the starting fluid. If it dies, pull the spark plug and check to see if it is wet. If so, too much fuel.

*if you try this with carb cleaner, the non-flammable kind will not produce the same result.

Is the intake boot ripped? Have you replaced the intake seal at the flange/head? Is the auto enricher stuck on?

Have you checked the fuel strainer in the tank? or if the petcock is plugged? If its mostly plugged, it could be dribbling gas slowly to the bowl, but engine may be emptying the bowl quicker than the tank can feed it.

How much fuel is in the tank? If it is too low, the "on" circuit may not be able to pull gas. Add more gas, and/or try flipping to reserve.