| Author | Message | ||
     Torx |
Hello, I read a similar post and have posted on another board. Just bought a one owner 09 Blast with 710 miles from military person who bought it in 2010 then got deployed. It sat in garage and wouldn't start. I put a new boot and a stock coil and it started. Also flushed tank 3 times w/93°and sea foam. Put fresh 93°and boot,plug, coil, plug wire. Started so took it down my rural road. It suddenly wanted to run wide open so I clutched it, got off road and shut it off it was revving so high. I waited a while, checked around and checked my drawers. Started it, idling fine,1/2 mile from home, give it 1/8 turn and let clutch out slowly and wham, the grass, dirt and gravel flew out from under me, I clutched in, hold on tight and killed it. Pushed it home. I cleaned carb, installed 170/45 jets,a air/fuel thumbscrew and idle thumbscrew. Checked and reseated flange and used another stock boot w/SSteel clamps. Checked idle and throttle cables from block to butterfly. Buttoned it up except airbox, started and idled great, no coughing, set air fuel at 2-1/2. Backed idle screw off. It didn't want to idle, but couple of turns on idle screw and she seemed great. Revving lightly, no smoke, little smoke from PCV fork but very little. It got warmed up, I gave 1/4 turn and it was revving almost immediately to wide open. Kill switch. Cool off, recheck cables for play and obstructions. Check exhaust manifold. New plug looked new. I am afraid to get on it if I am going to be running a whiskey throttle every time I am warmed up. Diapragm was pliable. Throttle valve seemed tight but didn't stick. I am wondering about ignition modules, TPS, auto enricher was about halfway and cleaned. Rubber vacuum plug looks sound. I hate dumping this as my first post, but I've done the diode and kickstand lockout fixes. New battery. The carb cleaning and jet change. Actually running better with no intake backfire. If anyone has any ideas, questions, suggestions, service ideas, I'll try anything at this point. I'm too old to 0-60 on public or private roadways in 3-4 seconds!! Thanks for reading this far. Safe Riding, VP | ||
| Reepicheep |
Based on what you have checked, if sounds like an internal carb issue. I'd pull it apart and clean it (which is kind of an art in itself, but which is very doable if you keep a "first do no harm" approach). | ||
| Gearheaderiko |
Really?? "Give the carb a good cleaning"??•••• Avoid the shotgun approach to repair. You'll just create more problems and questions. Why at 710 miles you'd think it would need anything is beyond me. I'm sure it didn't and now that you've taken everything apart, who knows where the problem is. Ask "what would allow or make the engine run WOT?" Not plugs or coil. Mostly it's going to be fuel related. Did you adjust the timing or mess with the TPS? At this point the first thing I would check is the piston diaphragm and spring, Needle and needle guide. If it only goes WOT after warm up, that tells me something is amiss after the auto enrichener comes off. Is the right slow jet properly installed? You might try unplugging the AE and see what happens. Is this bike stock? No modifications? Sorry, I may seem a bit harsh, but at this point it could be anybody's guess at where the problem is. Again, at 710 miles on the clock, it should need nothing-keep that in mind. | ||
| Reepicheep |
Erik, I'm not sure if you are insulting me, Torx, both of us, or neither of us. But it's not helpful or necessary. A bike that has only accumulated 710 miles of use in 7 years is going to have significant issues related to sitting. Some of them may be really unusual. That includes seals, fluids, and fuel system. It also includes a lot of really off the wall things. Torx, plug replacement was a good idea. A bike that sat that long and ran that little likely had plugs fouled to some level. The coil and plug wires likely had nothing to do with you symptoms, but you likely spent less for them then an hour of shop diagnostics would have cost, so no harm no foul. If you still have the old parts, throw them in a box as spares, they are probably still good. And if your replacements were sketchy quality aftermarkets, go back to the stock ones. Cleaning the carb was a good idea, but I've found that repeated carb cleaning is sometimes necessary for bikes that have sat with modern (awful) fuels, and consider a rebuild kit if you can find a cheap one. Seals were a good call also, as they are likely to suffer when bikes sit. | ||
| Torx |
Reap and Gearhead. Thank you both for your input and information. The coil was bought by the owner, from HD dealer. NGK plug and factory plug wire were also bought from dealer and NGK plug at the HD service manager suggestion. Previous owner bought them. I installed them and after checking original plug wire with ohm meter, I went back to it and stored the probably fine coil for a spare as mentioned. The bike wouldn't start so I bought a service manual and replaced the boot, and ran some sea foam through the carb, emptied it and let it dry. Same with tank and sloshed it out and cleaned the filter. It started running ok until it warmed up and almost took me on a road rash ride. I put 170/45 jets and cleaned the upper and seated the diaphragm and cleaned the whole thing. I added a air/fuel thumbscrew and idle thumbscre. Set air, fuel to 2-1/2 turns and put carb with a 2nd new stock boot and 93 octane and she started up. I checked throttle and idle cable routing, put some liquid graphite based lubricant into the throttle and idle cables as well as I could. Bike started and ran good. Until it got warmed up. Then a slight 1/4 turn and the engine behaved as if it was wide open. I am thinking about watching this happen while wearing eye protection to see what the throttle valve is doing. Maybe heat and throttle valve gets warped? Maybe disconnect the throttle and idle cables at the carburetor and see what happens. I wish I had a good running Blast to put my carb on and ser what happens. I'll certainly try anything and everything suggested. I'm not an ace mechanic but I do rebuild tractors and a couple of fuel injected trucks. I don't want to start any arguments or sound like I am an expert in anything. If I could get support from a qualified professional, instead of being told that parts and service is obsolete, I would definitely go that route. I have learned more from reading here than the service manual could ever touch. I appreciate and value and admire all the knowledge and experience I've found here. And my thanks can't be expressed for your help, knowledge and experience. And also your friendship to help out a guy who is afraid to get his low mileage bike out of nuetral. Sorry for typos, my eyes aren't what they used to be! Peace and safe riding. Torx | ||
| Torx |
I forgot to mention that the bikes is stock down to the tires. The only mods I've done was replacing the 170 jet with factory 170 jet, Pulled the 42 jet and replaced with a new factory 45 jet. I replaced the needle valve with factory, by factory I mean from local HD parts shop. I replaced the needle valve and ordered an emulsion tube. I used aftermarket idle thumbscrew and drilled out the plug the air/fuel plug carefully and replaced with thumbscrew. No other modifications. I cleaned the carb inside out with a can and a half of carb cleaner. Toothbrush and a small pipe cleaner. I turned throttle plate and scrubbed the whole throttle plate sides, front back and sprayed and brushed the attachment points as best as I could. The upper pin and guide looked great and the diaphragm looked and felt good and went into place with no sealant. I replaced the factory screws on the upper and lower covers with hex head screws. I looked at the Auto Enricher and it looked at about halfway. I cleaned it out with a small brush and carb cleaner. I didn't touch the TPS or AE. Unplugged the Duetch connector. I have never turned the throttle more than 1/4 turn when the bike is running. I have turned it when cleaning with engine off, but when riding it, I barely got out of second gear or past 1/4 mile. I have let it warm in neutral and I didn't turn throttle past 1/4 before it ran wide open. I have let it idle to warm with a shop fan blowing into the general area but only to keep some wind flow on engine and help keep exhaust fumes down. Plus its hot as heck here. The problem existed before the carb cleaning. It seemed to start and run smoother after I cleaned it. The upper was fairly dirty, but not terrible. The throat was fairly clean. I have to question the throttle valve as mentioned. I hope I've answered any and all questions. I don't know enough about the AE or TPS in this bike. I've been driven crazy by them in a couple of fuel injected vehicles. The boot is new and tight. I can see how I would carry a spare and replace at every opportunity. I am unsure what to do. I might have to buy a new carburetor. I'd gladly replace the AE and TPS. It's getting a lot of fuel suddenly and the cable linkage could be an issue. The spring is tight and snaps the throttle valve closed quickly. Notice 3 small holes at the bottom of the throttle valve at closed.Honestly I don't know what these tiny holes are for, but I assume it is for fuel spray. I don't know what holds the throttle valve inside the carb body or if they have seals. I assume that if the throttle plate ends up wide open, it would take some serious force, and not sure if the TPS or the AE would have any way of doing this. I'll unhook one, try it, unhook the next, meaning TOS and AE. What order should I eliminate thebAE and TPS and should I try separately, in a specific order or just unjook AE, try out the results then the AE etc? Again, thanks for my lack of proper terms and newness with what I think is a beautiful motorcycle. Thanks for your help with my many questions and I look forward and questions, directions and ideas. A little encouragement or information about a new carb is also a consideration. Thanks and have a safe weekend. Torx | ||
| Blake |
Running rich and has an air leak in the intake tract would be my guess. Running rich at startup is normal, and the Blast has an automatic enrichener, yes? The air leak acts like an opening throttle and it doesn't take much to get the engine revving. | ||
| Torx |
Air leak in upper diaphragm? New boot with sold clamps. I'm not sure where I should look for the air leak. Sounds credible and I am not sure where to look for air leak. It doesn't cough or backfire. I would be grateful if I knew where air could be leaking. I suppose that the rubber stopped could leak. Man, lot of force to hold throttle valve wide open. Like a leaf blower. Trying to be funny. Should I unhook the auto enricher and the TPS at Duetsch cable to rule out those two.? Replace upper carb? I'll replace the whole carb at this point. Too hard to watch my friends riding away into the 80 degree heat. Thanks for any pointers on air intake leak. Airbox off now. Naked carb. | ||
| Blake |
"At warm idle, I've never turned throttle more than 1/4 turn max then get the runaway and have to hit kill switch. First time, I was on side of road, gave her a little throttle, let a little clutch out and the bike opened up and luckily I got on the clutch and kill switch as the rear end came around and bike flew forward. I almost ate gravel and pavement 100' from my driveway. Checked my drawers and pushed bike home and its not left neutral since." Was it more than engine inertia due to the engine revving up that launched the bike out of control? If so, then it sounds like more than an intake air leak. Something more like a sticky throttle. It's easy to cause that via throttle cables mal-adjustment/routing. That's happened to me. It can happen at either end, at/inside the handgrip, or at the carb, or be due to too much counter-tension between open and return cables, or due to a kink at the carburetor or elsewhere. It just takes some careful inspection. You should be able to see if it is sticking by removing the airbox and air filter. With the return cable properly adjusted, even with a binding/kinked cable, you should be able to force the throttle closed by twisting forward on the handgrip. A competent motorcycle mechanic will likely be able to diagnose your problem in short order. | ||
| Ezblast |
Make sure the cables are not switched at the carb. EZ | ||
| Torx |
EZ. I've pulled the cables off at the carb and still get the runaway result. I've since pulled both cables from the bike, checked for kinks and have them labeled air and idle and have them hanging with the lithium based throttle cable liquid lubricant I found at a local bike shop, hopefully working its way through the cables. Once I have a Blast pro I met who is going to put my carb on his Blast to see what he has the runaway problem, I'll look here and everywhere for proper cable installation and adjustments. I appreciate your interest in making sure that the cables are properly installed, adjusted and maintained. I imagine that a good inspection before each ride will be a great idea. Thank you for your help and information. It's a definite point of failure or problems so after the carb is checked out and rebuilt by a Blast professional, I'll be treating the cables to your suggested maintenance and adjustments to be confident that they are safe and sound. I appreciate your interest in my problem and the help you have provided. Regards, Torx | ||
| Torx |
Hello Blake, Thanks for your reply and suggestions. As posted, I've removed the cables and will replace or reinstall them with care and instructions here there and from the manual or by a Buell mechanic if I make headway with the local HD service center. "A competent motorcycle mechanic will likely be able to diagnose your problem in short order" Very good information indeed. I am shipping my carb with new Buell/HD upper components as well as emulsion tube, needle jet etc. to a helpful mechanic who is a trusted member of the Buell community. I am grateful for his help and hope to see if the carburetor causes his Blast to rev out of control. I'm also getting it professionally rebuilt as needed and replacing the vacuum diaphragm and slide with Buell parts. Thanks for the pm and this valuable information to seek help. I fix and build a lot of things but as has been suggested, I'm letting the pro's look into this potentially dangerous and painful issue. Many thanks for all the knowledge gained and hopefully I'll be safely riding my new to me Blast real soon. Peace, Torx Durley | ||
| Reepicheep |
Nothing like a runaway throttle to drive home the real value of professional mechanic work!  | ||
| Torx |
"Nothing like a runaway throttle to drive home the real value of professional mechanic work! : )" Also saves on replacement costs of underwear after a runaway throttle! | ||
| Kenny_gilgore |
Has the above mentioned problem ever been resolved? I have the same general problem with the engine racing. I did notice when the bike is warmed up and I restart the engine the idle is right where it should be, if I twist the throttle suddenly the engine is racing at several 1000 RPMs. I have replaced the Super Boot with a new one from Dan and have checked for exhaust leaks. I cannot locate a professional locally that will take a look at it. Kenny G | ||
| Kenny_gilgore |
What does the Throttle Position Sensor do? Is it prone to failure? | ||
| Missionbolts |
It's likely a CV carb issue. You can only redo that intake boot so many times before killing vacuum leaks there 99.9999%! The TPS & AE are the only things on the carb that make it any different from standard CV designs - ie a hole in the slide diaphragm will tend to result in not being able to give the engine gas, as the slide is raised upwards only via engine vacuum becoming higher than airbox pressure. That forward butterfly simply modifies the intake vacuum/airbox(atmosphere) pressure ratio vs the return spring on that slide. Seeing as it sounds like the slide is jumping wide open, I doubt the diaphragm has any holes or leaks I would check the return spring on the slide. Initially, you can just stick a finger down the throat and pull the slide up. It ought to have a pound or two of resistance, and drop back down quick & smoothly Then I would eyeball the large port at the top of the carb inlet, that port provides atmospheric pressure to the bottom of the slide diaphragm. If that port is blocked off, the carb will act like you describe. Pulling the slide up, then dropping it quickly, you should note some small amount of airflow in & out of that port A jammed main needle or emulsion tube would be another thing to check, but it kinda sounds like the slide is 'raising up more than it should', not simply failing to return. However, this engine does have an aggressive intake pulse that might lift the slide momentarily higher than where you have the your throttle opened up to. That might possibly give a 'stair-stepping' effect in combination with a jammed needle, which could mean after the engine turns over a few times, the main slide will be higher than where you want it. Each intake pulse could potentially be giving a stuck slide an upwards kick that keeps moving it higher. This potentially might not show up with the engine off, if it's the needle slopping around under airflow Oh, and maybe check the needle is clipped securely down into the slide? Not securing the needle can give all sorts of funny results So I would try lifting the slide with the engine idling And try holding one finger lightly against the slide while opening the throttle just enough to re-create the issue. Maybe open the throttle right at the carb while somebody else is ready on the killswitch. If the slide feels like it's opening up in a jerky sort of way, that could be a 'stairstepping jammed condition' You might even go so far as to check the slides bore. If the front of the bore has any notches or burrs that only catch the slide with intake airflow pulling the slide forwards, but not while the engine is off, well that's kinda a long shot but maybe? I think the TPS is a way for the ignition module to estimate intake vacuum based on a lookup chart in combination with measured RPM. Ergo - this RPM with this TPS signal = this vacuum. This would be a software driven vacuum advance. But that's just my guess as to why it's even on there The AE circuit shouldn't be able to influence the slide action, as that's just adding more fuel to the slow speed circuits An intake boot leak will occur downstream from the butterfly, so closing the butterfly will still reduce intake vacuum at the top of the slide's diaphragm. I doubt this is an intake boot issue. Maybe the butterfly blade has come loose? | ||
| Kenny_gilgore |
Mission Bolts, Thank you very much for the technical knowledge that you have shared. Some of the information is above my pay grade, but I have a Harley mechanic friend that will understand it and I think he will help me. Thanks Again! Kenny G | ||
| Kenny_gilgore |
I had my Harley mechanic friend over to help me with the Blast. Before we removed the carburetor we went over the intake with a propane torch with out lighting the flame and went over the exhaust with a candle and could not find any leaks... My Harley mechanic friend disassembled the carb and found the emulsion tube and needle in good shape. The throttle plate is in good shape and functions smoothly. The slide is smooth and without play. The jets are all completely open. There is no tear or holes in the diaphragm. When the engine is racing the slide is in the full down position and the butterfly is completely closed. The only possible source of gasoline is the Automatic Enrichener. Disconnecting the enriichener from the Blast the idle is at normal speed. It doesn't run very good with the enrichener disconnected because the Throttle Position Sensor is part of the same circuit. I can go around the block and the speed is normal...…. Before this problem started I installed a new spark plug and a new coil wire from NAPA. The coil wire is a little longer than the OEM coil wire. Is it possible the electric in the coil wire could interfere with the signal passing through the auto enrichener? Kenny G | ||
| Missionbolts |
This gets more interesting! Everything I have considered so far is based on standard designs, but this auto-enrichener does throw a really big monkey wrench in the works, doesn't it? Personally, I'd be curious to see what happens if you carefully undo the pins in the connector so as to remove at least one of the wires going to the AE circuit. That circuit is powering a very small heating element which in turn heats a capsule of wax. The wax expands as it gets warm, which drives a piston. The other end of the piston has the fuel valve which is what the AE module is controlling. It doesn't have any trickery going on that could be called a 'signal', it just simply gets battery power when you fire up the bike. It's engineered to open just slowly enough that it's approximately correct for how long it might take for the engine to warm up. This AE design is the reason why these bikes get a bit cranky on hot re-starts. If the bike sits long enough for the AE to cool off, it has to go through another warm-up period while the engine is still hot enough that it doesn't need that extra fuel. Anyways, I think it's time to go back to the chalkboard on this one & trace out the AE fuel circuits. I suspect it might be possible that there's a way for the AE circuits to flow enough air & fuel to act like the throttle is open. Yet when unpowered, it still can close off the circuit to act like normal. Is there a chance the AE piston is missing a metering rod? I'm thinking I might have to tear my carb apart & look at it better Meantime, I just saw this youtube: https://www.youtube.com/watch?v=toYTwg2XR-0 I was only looking for something that shows the metering rod, but hey! I didn't know the AE can be adjusted like that. Maybe you could check that it wasn't adjusted wrong? | ||
| Kenny_gilgore |
Mission Bolts, I have seen the video that you are referring to on the other forum. That is one of Lee's Carburetor Videos, he has several of them. I am now getting past the age of figuring out carburetors with the exception of old Amals and 40 year old Mikunis.. I sent the video to my friend and he is not all that familiar with the Auto Enrichener and is thinking it would be better to start out with a new Auto Enrichener. With a new one we can compare the action of it with the my 9 year old one. Several years ago I saw a post somewhere on the internet where the guy converted the Auto Enrichener to Manual operation, but I can no longer find it Your help is certainly appreciated. Kenny G | ||
| Missionbolts |
Sorry, I seem to always put out more info than anybody else ever asked for! I've seen a ready-made manual choke conversion kit on a snowmobile forum. They had this same exact carb & were having issues with the AE not working correctly in freezing cold conditions Can't say I'd want to recommend against putting in a new unit! Your testing with the carb's harness unplugged does sound like it's going to be the AE system | ||
| Kenny_gilgore |
Missionbolts, I decided to order a new AE from St. Paul Harley and with the holiday and weekend it will be sometime next week until the AE arrives, and it will be a few days for my friend to be available. I am cautiously optimistic that the new AE will fix the problem. It is too bad that the other guys that have had this problem and reported it on various forums never posted what they did when they found how to correct said problem... Have a good Thanksgiving My Friend! | ||
| Kenny_gilgore |
The new Auto Enrichener arrived today from St. Paul Harley Davidson. I ordered it Wednesday and arrived the following Monday. Packaged in a sturdy box, that sure beats the way most parts are shipped.... My friend will install the AE this coming Sunday... Kenny G | ||
| Kenny_gilgore |
The initial test indicates that the new Auto Enrichener has corrected the problem. I will have to install the air cleaner and go for a test ride to be certain. Kenny G | ||
| Gearheaderiko |
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| Missionbolts |
All right, ridetime! | ||
| Kenny_gilgore |
I filled the tank with ethanol free unleaded gasoline. Started the bike up today and the Auto Enrichener kicked in right away. I had continuous spitting back through the carburetor for the first couple of minutes. When fast idle backed off I hopped on the bike and went for a ride. The engine was really rough running for the first few miles. I stopped a couple of times to adjust the idle speed. The only noticeable difference in engine performance today from a few months ago is that when coming into a stop it takes a few seconds for the idle speed to return to idle. I am thinking the carburetor needs some fine tuning and I have forgotten how to adjust the idle air screw. | ||
| Missionbolts |
Spitting back happens to my bike all the time, it seems to be running normal like that. I believe it's due to the intake port & manifold being too large = flow reversion at low engine speed. But I've also set my idle speed to a normal amount and not at 1200 like the factory manual calls for The AE controls fast idle speed, so having that kick down like it's doing is a good sign Idle mix adjustment screw is hidden under a plug. I forget which side of the slide it's on, but I'm thinking it was upstream. If so then it's an air-bleed: CW = richer |
