| Author | Message | ||
     Samato |
QUICK SUMMARY: After carb rebuild bike won't run consistently. Sometimes idles, at times it has accelerated. Sometimes won't start. Slide won't go up on it's own when given throttle. Fuel spraying out from intake/slide (out of carb, toward airbox). DETAILS: My father and I are working on a 2000 Buell Blast. The bike had been sitting for a while but would start and run, it was just very weak on acceleration. We have ridden other Buell Blasts and know they have more than what we were getting so it was time to take the carb off and clean it. Did that, put the carb back on the bike then it would not start. We've since had it on and off so many times I can't even count. We replaced the infamous manifold coupler (rubber boot) with a new one, as the old one was in bad shape but this did not really change anything. Replaced the spark plug. We've tested and adjusted the throttle position sensor as per the service manual and it is within spec. Jets and float seem to be fine but may require a more detailed investigation. We did find a rip in the diaphram and have replaced that. The brand new boot got ripped somehow (probably overtightened) so now we are on a 2nd new one. I think the plan for tomorrow is to drain the gas and start with fresh fuel. Then remove the float to check the needle and seat and adjust the float level again as well as another check of the jets. I'd like to blame this problem on the boot as it seems we have a vacuum problem but we've put checked and seated the boot the best we can and now have a lot of experience as to how not to do it. Does anyone have any idea what's going on here? Any advice on what to check/how to check? I'd be happy to post more information if needed. We're pretty close to giving up and taking it to someone but I really hate the idea, plus can't afford it. It's gotta be something simple we're missing right? | ||
| Gearheaderiko |
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| Kenster32 |
go back in time and drain the old fuel put in fresh fuel and some LUCAS injector cleaner and go ride it hard for 30min you can barrow my Flux Capacitor ken | ||
| Samato |
The above comments/animations are kind of funny and probably true but not helpful. I was told on another forum that this was the place to post this kind of question. Have I broken some rules here or something? Or is this just a difficult one to figure out? Thanks in advance to anyone who might be able to help. | ||
| Gearheaderiko |
Here's the deal-no offense: Description of carb problems are almost always preceded by "we took the carb apart to give it a good cleaning". Sorry, but its true "and a good carb cleaning" is rarely necessary (I preach that regularly). This thread really belongs in the "Diagnosing Problems" thread.You'll get help anywhere, but thats where all the info is. Follow the listing trail on the e-mail you receive (I know it can be difficult to find stuff here for the new person). http://www.badweatherbikers.com/buell/messages/201 64/150578.html?1247973212 PS welcome! | ||
| Swampy |
You have to be real careful getting the carb diaphragm in place. I put the cap on real loose and poke around the edges with a thin metal 6" pocket ruler. If you have the diaphragm pinched or torn it will not accelerate, it will idle and pop when you open the throttle but it won't rev up. | ||
| Samato |
Thanks and no offense taken. I realize there is a strong possibility we have done something wrong on the carb rebuilt (in fact, that much is obvious). Yes, it has been difficult to figure out where to post so I'll try where you said. | ||
| Gearheaderiko |
If it seems you have a vacuum problem, make sure the vacuum port on the carb is plugged. California (you dont have a CA bike, right?) bikes use the port for the EPA canister, all other states may have the port plugged, permanently capped or even not drilled for it. If you tightened the boot so much it split, then (obviously) you're tightening it too much. When the boot starts too mushroom, its too tight. The slow jet usually gets clogged from sitting. Have you done any modifications like new jet sizes or added shims to the needle? The needle jet (visible in the carb throat) can fall out when you pull the carb apart. Lots of carb info here: http://www.badweatherbikers.com/buell/messages/201 64/6812.html?1246766880 Do you have spark and compression? My guess is it wasnt a carb problem to begin with. Did you check compression with a compression tester? Low compression will mean a very hard start. 2000 model Blasts had the most oil pump drive gear failures. The bike could still start, but would run poorly. Do you have another carb available like from another Buell or Harley. They are basically the same carb, so if you have a good working carb you can swap it on and see how it runs. | ||
| Samato |
"You have to be real careful getting the carb diaphragm in place. I put the cap on real loose and poke around the edges with a thin metal 6" pocket ruler. If you have the diaphragm pinched or torn it will not accelerate, it will idle and pop when you open the throttle but it won't rev up." --------------------- Hmm, that sounds like what's happening. I think we've been really careful about seating and not pinching the diaphram but who knows?}} | ||
| Samato |
Gearheaderiko, Anyway you can direct me to a picture of the "vacuum port on the carb"? I'm not sure what that is but if it's what I think it is it's not plugged. I did overtighten the first replacement boot but I've since figured that one out I think. No modifications on this bike that I'm aware of. Definitely no shims. There is plenty of spark and there is compression, though I don't know if the compression is low. No compression test done. The only other carbs I have around are the 4 on my Nighthawk 750 and one on a 200cc Chinese enduro. I'm thinking of going to a local salvage yard to see what I can find. | ||
| Ezblast |
Make sure your vacuum line from carb body is fully plugged, plug wire is good, plug is good, check your exhaust header for leaks around the head, check that the vacuum line coming from the gas tank vent is neither kinked or closed or clogged. Swampy could be right, but also check that the front vacuum hole is not blocked either - area where the 3 front screws go around the carb's mouth. Last thing, the battery is not old right? EZ (Message edited by ezblast on July 21, 2009) | ||
| Gearheaderiko |
A metal fitting that has a small flare (or barb) that looks just like, but much smaller than, the fuel line fitting. It should be on the top of the carb, in the back (where the boot connects). There is only one and (as EZ stated) it should be fully plugged. Carbs come up on e-bay regularly for the HD/Buell twins (CV 40) . It should be noted that although the twin carbs are basically the same as the Blast carb, they are not a direct replacement. For the purpose of diagnostics, you can throw one on, but only a Blast carb will have the TPS and auto enrichener. | ||
| Ezblast |
Also check that the air screw is present and adjusted correctly - 2 to 2.5 turns out from light bottom would be a good range. EZ | ||
| Samato |
Well, I've checked everything mentioned here except I forgot to check for an exhaust leak - I'll do that the next time I'm in front of the bike. I've gotten nowhere. Same problem. Compression test results - 175psi (3 times in a row at WOT) Vacuum port on back of carb is plugged, front vacuum hole not blocked, vacuum line from tank vent is fine, diaphram is in good shape, boot is fine, plug and plug wire ok, air screw set to 2.5 turns. Not sure how old battery is but it charged and reads fine. We also tried with the battery from a bike that I ride everyday. We also checked the float needle and seat - fine. Float level is okay I think but I'm having a hard time figuring out how to do it exactly the way the manual calls for, still I think it's there. Besides, the float just needs to shut off when it reaches level right? It's doing that. Anyway, I don't think that would cause our problems would it? It still points to a vacuum leak I think because the slide does not go up when throttle is applied. We do have an overly rich mixture though because the plug was very black when we took it out. I think I'll have to research this oil pump drive gear issue as I know nothing about it. (Message edited by samato on July 21, 2009) | ||
| Ezblast |
Replace your jets. EZ | ||
| Gearheaderiko |
The battery and oil pump drive gear are unlikely causes. The battery can lead to poor running (rarely) and intermittent or no spark. The oil pump drive gear can lead to poor running (and lots of noise) but your bike would start if everything else was fine. 175 psi is good/perfect for compression. Does it start with starting fluid? Does the LED on the ignition module flash (or does it spark) every time it turns over? Or does it flash every third compression stroke? Does it flash once and then a few small flashes. I have to go on the assumption that it possibly wasnt a carb issue before the carb was taken apart. How many miles on this Blast? | ||
| Samato |
Only 9,000 miles on this bike. So you are thinking it was an ignition thing prior to carb clean/rebuild? We have not tried starting with starting fluid but my father used a spray bottle with gasoline in it and if I recall correctly it did not change anything. I'll have to verify that tomorrow I guess. I'll also have to check on the other questions regarding ignition module flashing. | ||
| Gearheaderiko |
Yeah, ignition is what I'm thinking. Electrical problems often seem like carb problems. I dont discount replacing your jets, since the carb has now been apart many times anyway. 45 slow jet. 170 main jet. If its not starting with starting fluid, then I doubt its the carb (though you might now have problems with the carb, but...). And you have replaced the plug with new. 10,000 miles is all you get out of a Blast plug usually. It may sound like we want you to replace everything. No, but we know the usual problems and since its not running at all, we have to go over everything. | ||
| Samato |
I'm considering replacing the jets tomorrow. The parts guy at the dealership told me the stock ones for a 2000 Blast are 42 slow, 165 main. Are you recommending 45/170 because that's proven to be better or was the guy I talked to mistaken? I'm pretty confident the carb is put together properly, though the heads of the jets are slightly damaged from using the wrong size screwdriver. Could that cause something this devastating? We did put a new plug in a couple of days ago. Right now I'm thinking if starting fluid doesn't do it tomorrow I'll forget about replacing the jets, forget about the carb completely, and turn my attention toward the ignition/electrical system - something I know even less about than carbs. Does this sound right or do you guys think I should replace the jets anyway? | ||
| Ezblast |
45/170 gives better results, and is a better safety buffer in case of a sudden lean condition. EZ | ||
| Gearheaderiko |
Concur! The guy was right, but after 2000 they used a 170 main and if you're going to replace them, you might as well do it with what is proven to work better. If you have fuel and compression and it still isnt starting, then spark is next. I'm suspicious of the slow jet, but if starting fluid doesnt produce any results I would spend a little time making sure of the spark. If it does start, then its back to the carb. Unless you know different, I always assume it ran fine from the factory and its still set up the same way. Then you're looking for a problem that occurred. That usually doesnt entail taking the carb apart (we covered that) or adjusting the ignition. What I'm saying is that things dont usually go out of adjustment for no reason. There's usually a failed or broken part that is the cause. If you do decide to adjust the ignition module, mark your starting point. (there was a case of early Blasts being mis-timed. However, this one apparently ran fine for 9000 miles). We should ask, just to be sure, that you havent done anything else to the bike. Didnt adjust the primary chain or have a wiring problem or the bike wasnt completely disassembled or ?? Even if it is seemingly unrelated to a running problem. itt should also be noted that we arent the ones pulling our hair out over the problem. We're just trying to come up with and eliminate ideas, in a logical fashion. We cant see the bike, so its all up to you. | ||
| Samato |
Well the bike starts and idles but chokes out when given throttle so I guess I'm still on the carb. I don't know what else to check because I think I've gone through everything but the auto enricher. Could that be responsible for what's going on. The guy at the Harley dealership told me the 2 most common issues they see are the manifold coupler and the auto enricher. I might just have to let them diagnose it because it looks like you need a special harness to test it and a new auto enricher is too expensive ($56) to buy unless I'm sure that's what it is. If they can diagnose it in 1/2 hour and it turns out to be the auto enricher it would cost me $42 (1/2 hour bench time) plus $56 (auto enricher), assuming I can put it on myself. (Message edited by samato on July 22, 2009) | ||
| Gearheaderiko |
The auto enrichener is an idle circuit. If it was stuck on it would choke at idle and run just fine when you gave it gas. Dont waste your time or money. If it wont accelerate, you have a different problem (not too say it couldnt be bad, but its not causing this problem) I would look at what would choke it out (and you do mean black smoke, not huff and stall). Incorrect jetting. Slide needle not installed properly. Needle jet missing (it may have fallen out when you took the carb apart). Vacuum piston spring not installed or binding. or? | ||
| Gearheaderiko |
Also, what did you gap the plug at? Are you sure you didnt bend it closed on install? (Happens a lot on engines where you're working blind and cant see the spark plug hole-unless you took the tank off). | ||
| Samato |
I have an open between pin 1 on connector 88a to pin 3 on connector 10b. This is the violet/orange wire that goes from the ignition module to the auto enricher. Also, the ignition module's red LED flashes every time (rapidly) the bike turns over. I can't find in the manual what this means - does it just verify that I have an open? (Message edited by samato on July 22, 2009) | ||
| Gearheaderiko |
Honestly, I dont know what that means with the 88a and 10b (and I'm not going to check). The bike will run with the auto enrichener unplugged (as well as the TPS unplugged). Its either stuck on, which mean it will start and load up on idle. Or its stuck off, which means it will hard start, but once its running and warmed up it will be fine. If its stuck somewhere between the two, it will have a combination of those problems. It wont cause it to choke out on acceleration. You might try holding the carb slide up with you finger and see what the bike does. If the idle goes up, it just went lean. If the idle goes up, it probably isnt a module problem. You might also hold the slide up and slowly open the throttle and see what happens.CAUTION this is a good way to get a burn if it backfires through the carb. Using gloves might be wise and do not stand or face directly in front of the carb opening. If the LED flashes regularly, its fine (its fine). You'd have to watch what its doing when its running and starts "choking out" to see if thats causing the problem, which will be tough to do. A weak spark (as implied by my 'check the gap'), could cause this problem, but the cause is usually the plug or wire or battery. A bad module could cause this, but I'm not convinced that this is the case (a bad module can cause a very wide variety of symptoms). | ||
| Samato |
First let me address the last questions: Not really any black smoke, sometimes white smoke/vapor from carb mouth. Slide, needle jet, piston have all been checked and as far as I can tell are installed and working perfectly. In addition to what I last wrote, here's the most recent situation: I tried several times to start the bike (even with starting fluid - would not start. I then hooked up my battery charger to the battery, removed the fuel tank, removed the plug - found the plug wet, fouled with gas. Not sure exactly what the gap is but it is definitely not touching. Replaced plug with a clean one (again not sure of gap but not touching). Replace tank, turn on fuel, bike starts and will accelerate, some popping at lower RPM's. After a few minutes bike stalls. Removed fuel tank, removed plug - plug not wet but extremely black. So now I'm wondering if the auto enricher not working can cause all of this. If not then I have the auto enricher problem AND something else. Either way, I think I must fix the open wire/auto enricher issue before moving on to anything else - right? | ||
| Samato |
The 88a/10b thing just means there is an open on the wire from the ignition module to the auto enricher. Before (yesterday), when holding the slide up with my finger and giving throttle the bike would accelerate - the slide would not lift on it's own though. Right now the bike will do what I wrote in my last post. Slide lifts on it's own when given throttle until bike stalls. Red LED on module continues to flash entire time until bike stalls, then it just stops. | ||
| Ezblast |
Disconect the auto enrichner, and see how the bike runs - still super rich, then replace jets. EZ | ||
| Samato |
Okay, I disconnected the auto enricher/TPS connector and started the bike. Exact same situation - runs and accelerates for a short time then stalls. I'll have to change the jets I guess. I just don't understand how that would cause this but then again there's a lot I don't understand. |
