09 Buell Blast running issue

[david thomas]

Hello fellow Buell enthusiasts. I was wondering if anyone could shed some light on my blast issues. Recently I had the Harley dealership pick up my bike and do a full diagnostic on it, as the bike was having issues starting and running. They claimed the battery was the issue, a fact that I had contested. Nevertheless, they put in a new battery and brought the bike back. The bike started right up, but as soon as I gave it some throttle, it would begin to choke and stall. I could technically leave it in idle without issue, but as soon as I apply more throttle to start moving, it chokes out and dies. Furthermore, right before it chokes and dies, it sounds like its backfiring through the carb. The stealership isn't too happy to be servicing the bike again and so I am pretty much on my own. One thing I did do, was take the carb apart and saw the fuel bowl gasket needed to be replaced, as it had warped and was not sitting properly in place. While this is an issue, it still doesn't explain what is happening. Any ideas would be quite welcome, thank you for reading this.

David

 

[34nineteen]

Sounds like a clogged main jet. Watch this and you will see how to inspect that and various other parts. Also check for intake leaks. If this is a bit over your head, I’d recommend just taking it to regular independent motorcycle mechanic (not necessarily a Harley shop). It’s a carbed single... not too much to go wrong with it.

https://youtu.be/_YbDLFoXtLI

 

[Cooter]

I totally agree with 34:19.
If it's popping through the carb when you give it gas off idle, it's going lean.

When you give it gas off idle it is transferring from the idle circuit (that's fine because it idles) to the main circuit (jet and needle) and going lean because gas can't get through it... the jet is clogged and a common problem.

IIRC a 170 is stock but you can go up to a 175 if you added a muffler or did intake mods. The jet size is the decimal equivalent of the drill size, so If you have a 170 drill you can clean it or open it up to 173-175 yourself. It's $6 new from HD and the same as an old Sportster.

Take off the float bowl again and the big brass thing in-between the floats, in the middle, is the main jet. A 5/16" driver and the whole assembly will pull out. The jet itself is a flat head on the end of that assembly. Clean all the little holes. Re-assemble. Boom.

 

[34nineteen]

Also, check to make sure the slide is opening when you open the throttle.

If it’s not, do this check...

https://youtu.be/lfQz4cxezAk


And be sure to put the jet holder back in the correct way if you get that deep into the carb.

 

[david thomas]

34nineteen and Cooter, thank you guys so much for the advice. I will be taking the carb apart again today and checking the idle and main jet for blockage along with ordering the carb bowl gasket since it needs replacing. If I may ask a question, when people mention an issue with "das boot," are they referring to the rubber fittings that connect the carb to the block? I feel like if it isn't an issue with the clogged jets, then it's an air intake issue or perhaps a control ignition module that is going bad. I know the module was an issue on the 2001 model, but I could have sworn the control ignition module is not lighting up the way it should, perhaps it is failing. Anyway, I will battle one thing at a time, starting with cleaning the jets. Also, I appreciate the two videos, I watched them both, and have learned an interesting little trick to check if the slide is functioning properly (properly pressurized) thank you!

 

[jetlee]

Make sure your needle jet is in the correct orientation. One end is concave, the other is flat. Flat end down, concave end should extend into the air stream. If it's upside down, it won't pull fuel up no matter what size jet you have in it.

Also, check the rubber diaphragm on top of the slide. If it has a tear or bad seal anywhere, it will not lift, which can cause your symptom.

 

[user_deleted]

I totally agree with 34:19.
If it's popping through the carb when you give it gas off idle, it's going lean.

When you give it gas off idle it is transferring from the idle circuit (that's fine because it idles) to the main circuit (jet and needle) and going lean because gas can't get through it... the jet is clogged and a common problem.

IIRC a 170 is stock but you can go up to a 175 if you added a muffler or did intake mods. The jet size is the decimal equivalent of the drill size, so If you have a 170 drill you can clean it or open it up to 173-175 yourself. It's $6 new from HD and the same as an old Sportster.

Take off the float bowl again and the big brass thing in-between the floats, in the middle, is the main jet. A 5/16" driver and the whole assembly will pull out. The jet itself is a flat head on the end of that assembly. Clean all the little holes. Re-assemble. Boom.

When you give it gas off idle it is transferring from the idle circuit (that's fine because it idles) to the main circuit (jet and needle) and going lean because gas can't get through it

i know you mean well but that is incorrect. whether it's a CV style or VM style carb....the progression of fuel metering steps is from idle circuitry----to intermediate circuitry----to main jet/needle circuitry. the intermediate circuitry is controlled by the pilot jet. simply do what Lee mentioned and plan on, at the very least, purchasing a replacement pilot jet. i stock them if and when you obtain the correct size/number needed. a few bucks each.

 

[Endopotential]

I learned a lot about tinkering on carb'd bikes with my old Suzuki GS500.

Not sure how much of this applies to the Blast, but figure some basic principles should still work.
https://joshkarnes.blogspot.com/2017/09/fixing-common-gs500-carburetor-issues.html

One good take away - resist the temptation to spray carb cleaner on rubber parts like gaskets, washers and the diaphragm - the solvent can eat away at them.

 

[Cooter]

i know you mean well but that is incorrect.

Read his symptoms before you post snarky pointless babble. Are you mad you can't sell him a Blast fuel pump? LOL.
If the pilot in the transition circuit was clogged it would stumble but still rev up once the diaphragm lifted the needle out of the main jet. Since it stumbles and dies, The main jet is probably clogged. Heck these carbs don't even have an accelerator pump.

OP: To get running: Clean the main jet. The big one. The one in the middle of the floats. Yes, you should remove the other jet while you're in there, in fact, you should re-build the whole carb and replace all the jets (if you're up for that).

Jetlee is correct about the needle jet, but you'd know if the carb was totally apart right before it wouldn't run correctly... and would have hopefully mentioned that. JL is also correct about the diaphragm (that controls the needle, that goes in the main jet you need to clean). If the slide doesn't move when you gas it, replace the diaphragm. It comes in the re-build kit I mentioned above.

"Das-boot" is indeed referring to the rubber boot between the carb and the cylinder head. Usually not a problem with a stock air cleaner assembly, is yours stock? Easy to check by spraying carb cleaner at it while idling (high vacuum) and listening for an idle change.

Good luck and report back what you find!

 

[34nineteen]

I learned a lot about tinkering on carb'd bikes with my old Suzuki GS500.

Not sure how much of this applies to the Blast, but figure some basic principles should still work.
https://joshkarnes.blogspot.com/2017/09/fixing-common-gs500-carburetor-issues.html

One good take away - resist the temptation to spray carb cleaner on rubber parts like gaskets, washers and the diaphragm - the solvent can eat away at them.

Informative article!

 

[jetlee]

Jetlee is correct about the needle jet, but you'd know if the carb was totally apart right before it wouldn't run correctly... and would have hopefully mentioned that.

You would be surprised how many people think the flat side should be up, so they don't mention it.

 

[jetlee]

I learned a lot about tinkering on carb'd bikes with my old Suzuki GS500.

I had an '84 GS500E, I hated that bike with a passion. The carbs are very similar. I ended up trading it straight across for a Remington 870 Express Tactical and have never once felt bad about it.

 

[Cooter]

You would be surprised how many people think the flat side should be up, so they don't mention it.

That^^^

and never checking the float height:upset:

 

[Endopotential]

I had an '84 GS500E, I hated that bike with a passion. The carbs are very similar. I ended up trading it straight across for a Remington 870 Express Tactical and have never once felt bad about it.

-Sorry for the thread digression-

Hey, I love my GS! Not like there's any place to shoot a gun in the Bay Area these days anyways.

Nowhere as much power or torque as the Buell, but so much lighter and easy to flick around. Granted, I modded it a bit..

 

[jetlee]

-Sorry for the thread digression-

Hey, I love my GS! Not like there's any place to shoot a gun in the Bay Area these days anyways.

Nowhere as much power or torque as the Buell, but so much lighter and easy to flick around. Granted, I modded it a bit.

I was excited when I got it, I had plans for it and really wanted it to pan out. Turned out it had a lot of issues and I was getting tired of fixing one thing to find another.

I didn't live in the Gay Area at that time, I had lots of county land and nearby ranges.

Yours looks really nice!

 

[david thomas]

Hey guys, thank you for all your help. Just a quick update. I took the carburetor apart, as previously mentioned, the carb bowl gasket needs to be replaced, as well as the paper gasket that bolts to the plastic cover. The jets were surprising clean, and the diaphragm was pressurizing the slide properly. I am still scratching my head as the same symptoms persist, except now in addition, my new battery that the HD dealership sold me, has discharged after several failed attempts by me to get the bike to not choke out when I applied the throttle (exactly like previous symptoms). I am still thinking it may be the ignition control module as I believe I have witnessed numerous times where the timing light was not lighting at all. I cannot imagine these symptoms would be caused by the gasket issues alone. Nevertheless, I need to replace these parts and finding them is more difficult than I thought. If anyone has any recommendations where I could order these parts from, I would greatly appreciate it. (The carb bowl gasket and the paper plastic gasket)

 

[david thomas]

I had an old 87 GSL850, first bike I ever learned on. The thing was a tank, I am telling you, rain or shine it fired right up. I am wondering if Suzuki still makes a good bike.

 

[Cooter]

If you aren't getting a light from your timing light, it isn't hooked up right. The bike would not run at all without spark. If you think you are having a timing issue, you'll need to get the timing light to light up first.


Its a CV 40mm Carb. Same as a Sportster. Pick your favorite brand of re-build. For $10 to $23 it's well worth the re-build. The parts alone won't fix it, you need to GET EVERYTHING CLEAN. Poke a wire into every orifice you can find:eagerness:

https://www.amazon.com/s?k=Harley+CV+40+rebuild&ref=nb_sb_noss

https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=Harley+CV+40+rebuild&_sacat=0

 

[Endopotential]

I took the carburetor apart, as previously mentioned, the carb bowl gasket needs to be replaced, as well as the paper gasket that bolts to the plastic cover. The jets were surprising clean, and the diaphragm was pressurizing the slide properly. I am still scratching my head as the same symptoms persist, except now in addition...

Sorry, you have me confused - you found all those deficient parts on the carbs, but then put the carb back together nonetheless, and then wonder why you're having problems? Seems like you need to get all the proper gaskets first (and replace all the perishable rubber bits as well), reassemble a properly restored cab, and then reassess. Not sure how you check out float bowl issues on a Blast, but a leaking needle valve there will also flood your bike.

Ditto on Cooter's comments. Can you get the spark plug to light up when you ground it out to the frame? Sure you have a functional timing light (check it on a running car or something)?

Just run it down one system at a time. And question all your assumptions. It's a good logic puzzle in many ways.

 

[david thomas]

Cooter, technically speaking, there were just 2 issues I've found with the carb as mentioned, one paper gasket that holds the plastic piece to the bolts, and the other was the carb bowl gasket itself. The paper gasket had a minor tear in one of the bolt holes and the carb bowl gasket was slightly warped, in my opinion, neither would cause these sort of symptoms alone. Furthermore, after not being able to figure out what the issue was, I put the carb back together and had Harley pick the bike up to do a full diagnostic. Since they were doing a full diagnostic on my bike, I put it back together the way it was, assuming they would find the issues regardless. Instead, they told me the only issue was the fact the battery was dead. Supposedly they did a full diagnostic but did not even find the carb issues that are quite apparent on sight. After receiving my bike back from HD with a new battery, the same symptoms persisted. So, upon advice from the good people here, I took the carb apart again to test the jets and the diaphragm. That took me less than a half our to do, so I put it back together after cleaning the jets to see if it would run. As I have reported, nothing improved, so now I am looking for those two gaskets to replace on the carb, really it's quick work. My gut is telling me it's the control ignition module going bad. There were times I had spark against the frame with the control ignition module lighting up, and other days, no spark and no light. I am aware this is more of an issue on the 2001 blast, and this is a 2009, but I am stumped as to what else it could be.