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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Help with mysterious mid ride shut down. /cgi-bin/YaBB.pl?num=1631679187 Message started by crujones on 09/14/21 at 21:13:07 |
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Title: Help with mysterious mid ride shut down. Post by crujones on 09/14/21 at 21:13:07 Hi everyone. I've been lurking for a while taking in a lot of information as I recently acquired a pretty rad 2003 LS650 Bobber build. I have no history on the motor, total milage or what is being run in the carb currently. I can tell you it's a stock carb(jetting was modified) with straight pipe and KN pod filter. I've put a thousand or so miles on it in numerous temperatures and for the most part, the bike runs fantastic except for three seemingly mysterious situations far apart from each other. Here's some details for background on how it's running. -The previous owner had no details on the bike for me but did say it could use a new spark plug, battery, tune up etc... which I did before even firing it up at all...The only thing that stood out was I ordered a standard OEM plug and the plug that came out of the bike was a colder one. I've been running the stock recommended plug and pitched the colder one. -The bike starts easily each time in different temps. -Surges a bit when cold, but doesn't hesitate or bog at all when at operating temp. -Idle seems consistent and doesn't stall easily even when cold. -backfiring is present on decelerations and in between some shifts. -Has a sportster tank with Sporty petcock so I know that's not the issue. Here are the three scenarios...They happened far apart from each other and overall engine performance has not changed at all out side of these moments. First scenario: Bike was roughly 10 miles into my commute home. Got to an open road and decided to see what she had...in 4th gear giving er pretty good was just about to shift to 5th when bike had an immediate power loss. It didn't shut off completely but giving throttle made no impact. I downshifted and after a few seconds of engine breaking in 3rd gear giving random twists, the throttle came back to life and the bike ran flawless again. Second scenario: Similar time into riding as scenario 1...Same 4th gear throttle maybe giving it more than it wants to have. Same power shut down happens right as I was about to shift up to 5th, the engine didn't turn off, again the throttle just became inactive. I did the same thing as the first time, down shifted, used the engine braking and gave it a couple twists of the throttle. This time when the throttle came back it was with a mammoth backfire! Loudest one I'd ever heard. Ran great after that again for a few more weeks. Third time was different. This time it was right after a tedious slow speed 10 min traffic crawl. I finally turned onto a road that wasn't going 20mph and just throttling up to normal speed early in third gear it did the same mysterious power shut down...Only this time, the throttle did not come back. The bike came to a complete stop and finally stalled on the side of the road. However it started up very easily after I turned everything off and back on again. Rode perfect the rest of the way home. I feel like it's a fuelling issue but before I go down the jetting rabbit hole...I wouldn't mind some advice on what else could be causing this since it runs so well side from these freak random instances. Thank you for any advice. Sorry for the long post! Didn't want to leave out any details. |
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Title: Re: Help with mysterious mid ride shut down. Post by verslagen1 on 09/14/21 at 22:21:42 1st and 2nd scenario tell me it's a fuel delivery too. -what size line does the petcock have? 1/4" is too small for WOT. -filter? -vent lines open? 3rd scenario tells me it's an electrical issue. -all you did was flip the switches and it ran again? |
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Title: Re: Help with mysterious mid ride shut down. Post by Dave on 09/15/21 at 03:10:23 Does the bike still have the stock vacuum operated petcock? |
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Title: Re: Help with mysterious mid ride shut down. Post by crujones on 09/15/21 at 07:03:07 42514647585553515A05340 wrote:
I'll check the exact size of fuel line but I'm pretty sure it's the standard size. Filter is clear and vent lines are open from what I can tell. Yes, I turned the bike off completely, ignition and all when it shut down but that was just instinctual on my part. Not convinced the switch or anything had anything to do with it... |
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Title: Re: Help with mysterious mid ride shut down. Post by crujones on 09/15/21 at 07:03:52 310A0710010D16100B030E11620 wrote:
No, Bike has Sportster tank with an HD petcock. |
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Title: Re: Help with mysterious mid ride shut down. Post by verslagen1 on 09/15/21 at 08:36:31 3B2A2D3237363D2B580 wrote:
I would check the switches, clean and lube. filters can restrict the flow. I'd get rid of it at least as a test. |
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Title: Re: Help with mysterious mid ride shut down. Post by oldNslow on 09/15/21 at 08:54:52 The OEM petcock on HD sportsters has been vacuum operated since around '95 up until '06 when they became fuel injected. They don't seem to cause problems as often as Savage petcocks do but folks still modify them to remove the vacuum feature. The HD valves don't have a prime position like the Suzuki's do, so it makes it inconvenient to drain the tank. Need a vacuum pump like a Mighty-Vac or similar to open the valve without engine vacuum. If your tank has an OEM HD petcock and no vacuum line running between it and the carb, your petcock may have been tinkered with. https://www.hdforums.com/forum/carburetor-related/1272430-vacuum-bypass-the-petcock.html http://xlforum.net/forums/showthread.php?t=524246 |
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Title: Re: Help with mysterious mid ride shut down. Post by Serowbot on 09/15/21 at 08:59:50 HD petcocks go bad exactly like Savage pets. It's in the nature of vacuum petcocks to give out. It's also possible that your tank vent is clogged. |
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Title: Re: Help with mysterious mid ride shut down. Post by crujones on 09/15/21 at 10:34:39 Sorry for my poor description of the petcock. The petcock on it is probably not Genuine HD. But I can confirm it is not vacuum operated. Just a standard on/off/reserve. |
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Title: Re: Help with mysterious mid ride shut down. Post by bobert_FSO on 09/15/21 at 10:35:46 "Filter is clear" Is this an aftermarket inline filter spliced into the fuel line? They sometimes have trouble passing fuel and developing air bubbles in gravity-fed fuel systems. I agree with Verslagen. I'd ditch the fuel filter, at least until you find a problem somewhere else. |
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Title: Re: Help with mysterious mid ride shut down. Post by crujones on 09/15/21 at 10:38:48 3A293E3F202D2B29227D4C0 wrote:
I would check the switches, clean and lube. filters can restrict the flow. I'd get rid of it at least as a test.[/quote] Because the problem is so intermittent. I wouldn't imagine that taking off the filter would tell me anything since it starts and runs just fine pretty much all the time. In between these issues I did do a complete new bar swap where I would have address and issues with the handlebar switches. The only switch I havn't looked at yet is the sidestand safety switch. I'll check that next too. |
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Title: Re: Help with mysterious mid ride shut down. Post by justin_o_guy2 on 09/15/21 at 10:49:02 I understand why you would not condemn the filter. But, you can eliminate a potential issue with almost no hassle. Recommend inline filter delete. If, after the problem is solved, you want to put it back,, cool. Or start picking through electrical, hunting an intermittent problem. I'd pull the filter and Pray that is it. |
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Title: Re: Help with mysterious mid ride shut down. Post by crujones on 09/15/21 at 14:19:22 Sorry All! My reading comprehension has failed me. I thought you were referring to the air filter! I assumed that because the bike does not have a fuel filter on it. Nothing outside of the tank anyhow. Fuel line goes direct from petcock to carb. Thanks for all of your insight so far! |
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Title: Re: Help with mysterious mid ride shut down. Post by justin_o_guy2 on 09/15/21 at 20:55:59 I'd get a glass jar and drain the bowl, and hope it has some crud it. Even if it's okay, I'd drain some gas out of the tank, into a clear jar. If you let the gas just drain and it slows down, that would point toward the tank vent. |
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Title: Re: Help with mysterious mid ride shut down. Post by justin_o_guy2 on 09/15/21 at 20:57:14 Are these problems happening when you are low on fuel? |
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Title: Re: Help with mysterious mid ride shut down. Post by crujones on 09/16/21 at 11:33:57 233C3A3D20271626162E3C307B490 wrote:
I can't remember each time but it seems to be happening at a mid-high level fuel point. But the tank is on a pretty steep angle so, it could be considered low even at what I think is mid level due to the angle. I know the tank has an aftermarket RSD fuel cap. I'm sure it's vented...but how well I'm not sure... |
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Title: Re: Help with mysterious mid ride shut down. Post by justin_o_guy2 on 09/16/21 at 15:19:12 If you are uncertain about the venting With a full tank Get a gas can and drain the tank. If you can see the flow rate drop Pop the cap If you see it go back up You may have found something |
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Title: Re: Help with mysterious mid ride shut down. Post by ohiomoto on 09/16/21 at 20:10:04 The problem us your diaphragm/slide assembly. My bike did the same thing while accelerating once. Just dropped all power after shifting, bit came back before I rolled to a stop. Another time I pulled out of my drive and it was low on power and wouldn't go beyond 20mph. My bike already had a raptor petcock. I went home, shut it down, poked around for a few minutes and it ran perfect when I restarted the bike. This exact same thing happened to me previously. I had done some jetting and it wouldn't go over 20 mph. I figured I lost vacuum on the slide. It looked good when I pulled it out and the bike ran perfect after input it back together. That was my clue. The coating on the slide was worn and it would stick. So the butterfly opens up, but the slide doesn't open. It creates a lean condition that fixes itself as soon as the slide comes free. Clean or replace the slide. I replaced mine and it was the best $120 I ever spent on my bike. |
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