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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Engine missing / stalling after 80mph (help!!)... /cgi-bin/YaBB.pl?num=1425492609 Message started by blackhalo on 03/04/15 at 10:10:09 |
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Title: Engine missing / stalling after 80mph (help!!)... Post by blackhalo on 03/04/15 at 10:10:09 Hey guys, I really need some insight with this one... it's been driving me crazy for the last year... this is generally how it goes: 1) Hop on bike and run 50 miles at highway speeds (no problems) 2) Stop for lunch for an hour 3) Gas up and get back on the road (no problems) 4) Within 5 minutes hit highway speeds of 80mph (no problems) 5) Cruising at 80+ for a few minutes and bike begins to miss and sputter (it will eventually stall if I keeping throttling it). 6) So I back off the throttle and coast for a second... 7) she'll usually release a nice backfire like she couldn't breath (I have a Supertrapp exhaust)... 8) then I do a LOT of systematic on/off twisting to keep it running in the 70+ range (kinda like burping a baby)... 9) she sounds like she's gonna choke and die the whole time... rev/cough/sputter 10) Here's the thing... I do that for 5-10 minutes... then it clears itself out and the bike begins running solid again. This happens like clockwork if we do highway runs... in the city, I don't ever have this problem. Carbs aren't my strong suit... but I can't help get this mental image that there's some gunk blocking the top-end needle... gunk that gets floaty after the first highway stretch... then settles during lunch... and clogs during the next top-end highway stretch. I don't mind yanking the carb out (though I'd prefer not too right now)... but I'd like to hear some ideas on what this could be? If it is just gunk (bike has 26,000 miles from the last 2 years riding), is there a fuel additive I can try first? I need to fix this, it holds everyone up (and freaks them out), every time we ride out of the city. :/ Thanks guys, any insight is appreciated!! Jay |
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Title: Re: Engine missing / stalling after 80mph (help!!) Post by Gary_in_NJ on 03/04/15 at 10:44:19 When I was 12-13 I had a TS-50 that would run at WOT for only a minute, then the plug would foul. If I backed off the throttle and nursed it a bit through a lot of backfiring and surging, the sparkplug would eventually clear and the bike would run normally at less then WOT. If I didn't get it through the rough period and stopped the bike, it wouldn't start for 30 minutes or so. The main jet was too rich, so the problem would only present itself at the rare times that I had sustained WOT (like riding on the roads illegally). The reason I tell this story is because it sounds just like your problem - BUT - it would be unusual for a stock carb to be too rich. Unless you failed to mention that the carb had been rejetted at some point. If that's the case, drop down one jet size. |
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Title: Re: Engine missing / stalling after 80mph (help!!) Post by bobert_FSO on 03/04/15 at 10:45:31 You are probably running out of fuel. Do you still have the stock vacuum operated fuel petcock? Running at 80mph is a low-vacuum condition. I had a similar problem. At 65mph and a stiff headwind, my Savage would start running poorly, then just quit. The same symptoms as running out of gas. If I switched the petcock to prime, fuel would begin flowing again and the engine would pick up before I could roll to a stop. In my case, the vacuum petcock didn't leak, it did the opposite. The diaphram got stiff and needed a lot of engine vacuum to flow fuel. Under low vacuum engine conditions, the petcock couldn't pass enough fuel to keep the float bowl filled. Solution: Get a Raptor petcock. |
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Title: Re: Engine missing / stalling after 80mph (help!!) Post by verslagen1 on 03/04/15 at 10:51:46 424C41434B48414C4F200 wrote:
take 2 petcock tests and call us in the morning. |
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Title: Re: Engine missing / stalling after 80mph (help!!) Post by Ed L. on 03/04/15 at 11:24:13 Had the same problem with my '02, put a Raptor in it and haven't looked back since. Stage 1 cam and new jetting, looking for the ton. |
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Title: Re: Engine missing / stalling after 80mph (help!!) Post by blackhalo on 03/04/15 at 11:46:20 Thanks guys... hadn't considered the petcock could be the issue! I intended to play with the Raptor eventually, but my bike runs quite well otherwise (not rushing to mess with my daily runner)... this issue is consistent though, and it's wickedly annoying on out-of-state trips... guess it's time to play! Thanks for the perspective! |
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Title: Re: Engine missing / stalling after 80mph (help!!) Post by justin_o_guy2 on 03/04/15 at 11:47:06 Classic petcock issues... don't buy the cheap one online. |
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Title: Re: Engine missing / stalling after 80mph (help!!) Post by Sundog on 03/04/15 at 11:47:27 On many bikes it's as simple as pulling the float bowl and cleaning out water and dirt particles which can get sucked up and fall back to the bottom alternately. You might giver it a shot. I had a similar problem when the neighbors cat was sneaking around and spraying my tires with cat pee. Made the problem harder to diagnose. Had to wash the tires to get near the bike. What a stink. At first I thought maybe the bike was just humiliated and stalling out of spite. Good luck. |
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Title: Re: Engine missing / stalling after 80mph (help!!) Post by Dave on 03/04/15 at 11:57:10 First and easiest thing to try....is switch the stock petcock to Prime and see what happens. |
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Title: Re: Engine missing / stalling after 80mph (help!!) Post by Art Webb on 03/04/15 at 12:05:11 Yup, did that with mine on day 1 |
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Title: Re: Engine missing / stalling after 80mph (help!!) Post by Kris01 on 03/04/15 at 16:34:58 Out of curiosity, how much oil are you burning at a constant 80 mph? |
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Title: Re: Engine missing / stalling after 80mph (help!!) Post by Bubba on 03/05/15 at 08:16:24 I also vote petcock...raptor is the way to go... BTW, at 26000 miles I'd pop the clutch cover off and take a peek at your cam chain tensioner...that thing is gonna blow... Do a search for verslavy mod... |
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Title: Re: Engine missing / stalling after 80mph (help!!) Post by Boofer on 03/07/15 at 02:53:20 blackhalo, I'm like you about messing with my bike unless it's broke, but the Raptor is a 15 minute fix after you drain the tank. Raptor petcock is Yamaha part number 5LP24500-01-00. I didn't even remove my tank to swap it out. Just bag the old petcock and vacuum hose if you want to keep original parts. Be sure to plug or cap vacuum tube sticking out of right side of carb. And you really do need to check your cam chain from 15-20,000. Mine was just getting ready to drop the adjuster at 20,000. Good luck. Boofer |
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