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Buell Forum » THUMPer Forum » Buell Blast Thumper Knowledge Vault » Diagnosing problems: » Starts ok, then quits. « Previous Next »

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Dantes_buell
Posted on Thursday, April 19, 2012 - 07:54 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I have the Superboot, and cut/tied the kickstand wires. I also adjusted the idle speed (NOT mixture) a little higher because it has sounded very bogged-down, however, the bike seems to run for an even shorter amount of time now.

here's a video:

http://www.lpvisual.com/Buell%20Blast%20Bad%20Star t.mp4

Ideas?
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Ezblast
Posted on Thursday, April 19, 2012 - 10:19 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

You have a vacuum leak somewhere - tore slide, vacuum line cap, bad o ring, supper boot not on right, stuck float, intake vacuum clog - check - also clogged fuel line - that huff was way too loud for a stock bike.
EZ
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Justotech
Posted on Thursday, April 19, 2012 - 11:39 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I was having this problem earlier in the week and read the common carb issues posts then found where someone had bumped up the idle a little so, I was trying to figure out how to get to the idle screw and noticed I had a gap in my breather box. I pulled the cover off and found that I had the wrong air filter installed so, it was about a 1/4 inch too long. I actually sealed my air box with duct tape until I feel that I can afford to buy the K&N made for it.

I went ahead and bumped the idle up by half a turn, after sealing the gap. I also looked at the hose clamps on my boot and tightened them up a little. After I did all that I rode around my neighborhood for about an hour without so much as a sputter. I'm still not going to ride the bike to work in the morning but, I think I made some headway.

If you're wondering how to get to the idle screw:
Take the seat off then take the bolt out that holds the tank cover under the seat and pick up the cover a little bit.

2002 Blast P3
7500 miles
Jardine RT-One Exhaust
New tires
LED Blinkers
HID Head Light

(Message edited by justotech on April 19, 2012)
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Bluv21
Posted on Thursday, April 19, 2012 - 11:55 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

The bike should operate no matter if there is an airbox on there or not. The air filter only filters out particulates like dust, pollen etc. What EZ was referring to was a vacuum leak somewhere within the CV carb or Das Boot.
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Ezblast
Posted on Friday, April 20, 2012 - 12:29 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Seems like tightening sealed the leak! Good job! Singles vibrate - things can get loose.
EZ
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Dantes_buell
Posted on Friday, April 20, 2012 - 08:55 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I doubt it's the Superboot. After a struggle, I prevailed. Here's the story:

When I first put the boot on, I got it on to the pipe first, and then pushed the carb into it. It DID look pretty wonky, but I went ahead and tightened everything up, started the bike, and the power popped the carb right out! Rinse and repeat, right? So this time I put the boot on the carb, and THEN pushed the whole assembly onto the pipe and it looked like a solid fit. I tightened the boot up more than before (I can see a little bulge from the rubber on the pipe end), and all seems well with that part.

Didn't fix my problem. However, I don't consider it a waste...it's still an improvement to the design...I would just like to be able to start the bike, then have enough time to put on my helmet and gloves without the thing quitting.

How exactly should I troubleshoot all of those vacuum problems with the carb?
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Bluv21
Posted on Friday, April 20, 2012 - 09:59 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

If you have a service manual you could easily identify these parts of the carb. If not, send me a PM and I can send you the carb section of the manual in PDF.
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Dantes_buell
Posted on Thursday, August 02, 2012 - 05:52 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

OK, still having problems with this...

I realized the manual illustration didn't quite match my bike...turns out I have the shiny replacement timing cover, meaning someone was in there up to something.

For some reason, the allen wrench size looks to be a 3.5 (unless there's a fancy Harley tool) so I can't even get a look at what's going on for a few days. Oh yeah, oil is visible on the wires coming out of the case (the ones leading to the ignition module...anyone wanna bet it's shot?). So I will likely need a cam shaft seal, but I couldn't find info about that part #


Aside from that damn module, is there anything else that might cause backfiring to extent that the SUPERBOOT has popped-off 3 times in the last few hundred miles? My theory was that it is SUCH a great seal, that the air wasn't able to escape like it did out of the stock boot. No?
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Ezblast
Posted on Thursday, August 02, 2012 - 10:18 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Is the intake gasket blocking the vacuum?
EZ
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Crackhead
Posted on Friday, August 03, 2012 - 08:36 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I believe most of the replacement time covers use standard allen screws, i think 1/8 is the cross over size.
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Dantes_buell
Posted on Friday, August 03, 2012 - 02:17 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

EZ - What vacuum, and how can I tell that?

Crackhead - I have a set of standard and metric...5/32, and #4 are too big. 1/8 and #3 are to small.
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Ezblast
Posted on Saturday, August 04, 2012 - 10:10 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Three screws hold the intake to the carb, forth hole is a vacuum hole for the float. If that gets blocked - that can be a result.

Try a 4.5mm, and replacing the seal is easy, just mark exactly where the ignition and cup are and put them back in the exact same position and you'll be fine.
EZ
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Dantes_buell
Posted on Friday, August 31, 2012 - 04:00 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I have had it with this bike. I'm in grad school and need to spend my weekends studying, NOT troubleshooting problems with a motorcycle.

Last week I adjusted the static ignition module timing (was off a couple degrees). Today, I just adjusted the Throttle Position Sensor today (to .5V on the nose), and looked for cracks in the Auto Enrichener gasket - none found. As far as I can tell, nothing is blocking the vacuum hole that I can see.

After starting, it backfired and blew off the Superboot about an inch. I put it back on, restarted (and kept of having to restart because it boggs-down and quits) and then finally it backfired AGAIN and blew off the Superboot about an inch and a half again.

So. What is it about adjusting the Timing and Throttle Position Sensor that could now be making it worse? Also, would a cracked Venturi ring (around the screws) have anything to do with this? For the record, I did NOT replace the carb gasket, well, because I don't have one. Issue?
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Sycho
Posted on Saturday, September 01, 2012 - 12:32 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Just outta curiosity try starting it with the kickstand up. Then put it down to see if it bogs down and quits.
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Dantes_buell
Posted on Saturday, September 01, 2012 - 02:02 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

"Posted on Thursday, April 19, 2012 - 07:54 pm:

I have the Superboot, and cut/tied the kickstand wires"

You sill think that's a factor?

Just in case, I ordered a carb gasket and will replace that. I mean, since the backfiring became worse after adjusting the TP sensor attached to the carb, perhaps I did not align it properly once I put the airbox back on.
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Dantes_buell
Posted on Wednesday, September 12, 2012 - 06:12 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Alright, I got a couple videos for ya'll to check out...

Ok, first link = Start while on the stand, leaning (diode is flipped, stand disconnected). Note the uneven running towards the end:
http://www.lpvisual.com/Start.mp4

Second link = Restarted while sitting upright. Note that when I lean it back on the stand it begins to run unevenly. It does not quit:
http://www.lpvisual.com/Start2.mp4

Thoughts?
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Dantes_buell
Posted on Monday, September 24, 2012 - 10:50 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

OK, I took the blast out for a spin after sitting for 11 days. It now has comPLETELY reverted to the original problem, showing no signs of improvement that I noticed earlier after adjusting the static timing, throttle position sensor, and new carb gasket.

In fact, it backfired so much and popped-off the Superboot enough so the engine quit and I had to stop and get the thing back on. In the past, it at LEAST has gotten me back home.

I am nearly to the point of selling this, but it would only do any good to be in the hands of someone who knows these machines...well. Before I do that, however, are there ANY more ideas on what would cause such violent backfires?

Thanks.
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Dantes_buell
Posted on Sunday, September 30, 2012 - 02:00 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

OK, day 2 problem-free. The latest adjustments were idle mixture screw and vent tubing (gas tank and one from pcv valve) rerouting. I adjusted the idle mixture out 2 and 1/2 turns, but then it was running funky so I screwed it back in about 1/2 turn while running and the pops went away.

Does anyone know what the stock mixture is set at? (Yes, I forgot to note where mine was before I gently seated it.)

Since I am running stock jets, I assumed the mixture was too lean, which led me to believe I needed to back out more than 2 and 1/2 turns. Does backing out, then, create a leaner mixture?
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Styxnpicks
Posted on Monday, October 01, 2012 - 04:35 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

stock jetting is pretty lean from the factory
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Dantes_buell
Posted on Monday, October 01, 2012 - 04:46 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

So how does that mixture screw work?

Screwing in = leaner
backing out = richer

?
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Dantes_buell
Posted on Tuesday, October 02, 2012 - 01:49 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Engine is running WAY hot. I have some oil bubbles around the dipstick and when unscrewed steam comes out. Hot frame, HOT header.

The idle-mixture has been anywhere from 2 and 1/2 to probably 3 and 1/2 out. If it's screwed in further than 2 and 1/2, I get backfiring.

ANY thoughts?
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Dantes_buell
Posted on Friday, October 05, 2012 - 01:20 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

OK, rejet kit is on its way and I will make sure the float is not out of position.

Also, it appears I need to replace the front isolator. Here is a link to another thread I started that may or may not have anything to do with problems of overheating and backfiring:

http://www.badweatherbikers.com/cgibin/discus/show .cgi?20164/695269
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Dantes_buell
Posted on Friday, October 05, 2012 - 02:19 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Approx. half of the pics I see show the fuel inlet fitting at an upward (or downward at this orientation) angle. Does this have ANY affect on carb performance? Should I adjust mine?




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Dantes_buell
Posted on Friday, October 05, 2012 - 04:28 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Providing that I get a new isolator and the rejetting works out, the following just happened which might explain quite a bit:

I just discovered millimeter(s) worth of "built-up" around the manifold and corresponding part on the carb. It was fairly simple to scrape off. I am convinced that no matter how securely I put that boot on, it was not creating a proper seal.
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