SuzukiSavage.com - Explosion

ohms

Ex Member

Explosion
08/16/06 at 14:50:43

Hey guys,

I dont know what the hell is going on now, but sometimes not all the times when i start the bike a huge explosion goes off, i guess a big backfire. It is extremely loud. The first time I my ears were ringing. The second time was more embarrasing Shocked

. The bike runs perfectly otherwise, just this huge bang on startup. Not sure what could be causing this, the bike doesnt backfire while riding or when i turn it off.

Any ideas?

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Trippah Serious Thumper Offline I ride, therefore I am. Posts: 2517 central Mass Gender:	Re: Explosion Reply #1 - 08/16/06 at 19:14:53 A little more info, such as year and milage on bike. Obvious first thought is too much fuel/too rich in carb on start up. Does it crank several times or a lot before firing?? That kind of info. As Sherlock would then say..the games' afoot.
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Brendan

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Posts: 37
Canberra, Australia
Gender: male

Re: Explosion
Reply #2 - 08/16/06 at 20:25:57

Mine does it upon shut off, sounds just like a firecracker going off! The weirdest part is that sometimes it will do it 3 or 4 seconds after the engine has stopped turning over. Like yours my bike runs perfectly, starts first throw and NEVER backfires when running.

Im going to adjust the pilot circuit as per the instructions found on this site. That should fix it. As for yours Im not too sure...sorry!

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1986 Savage, 2001 YZ250 (what a bike)

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sluggo Serious Thumper ModSquad Offline big singles lead, twins follow the pack Posts: 4744 moses lake washington Gender:	Re: Explosion Reply #3 - 08/16/06 at 23:20:25 it's just announcing it's presence.
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Fat Bastard

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Gender: male

Re: Explosion
Reply #4 - 08/17/06 at 00:35:08

Same here.. (somtimes)when I push the start button it sounds like a really loud gunshot.. (button in = PAAAAAANG) ... It backfires a bit when I drive down slopes but not much and nothing at shutoff.. (sometimes a pathetic "Buuff" and that doesn't count as a backfire) ...
The strange thing is that before I installed a SE muffler it didn't do this at startup... but at shutoff... so after the SE mod the PAAAAANG moved from shutoff to startup. Why? and with the original muffler it backfired more when driving..... I have not done anything to the carb... but I'm sure that previus owner did..
I also put in a new sparkplug (normal heat range) when I put the SE on.

1997 . 40000 KM

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ohms

Ex Member

Re: Explosion
Reply #5 - 08/17/06 at 04:10:49

Well its a 96 about 16000 kms. I put on a jardine pipe and the carb is rejetted to 152.5 main and 55 pilot. The spacer mod is done as well. I have a K&N drop in as well. I farted around with this for ages already trying to get the right mix and right jets backfiring here there. Mustve swapped the jets 20 million times fixed header leaks, muffler leaks, intake boot leaks. It's been one long ordeal. Just when u think its running great now, I get this BANG!!

I normally use the choke to start and it starts very easily. But there was time when i would have to crank it for ages b4 it would start. Perhaps its too rich in the carb possibly? Undecided

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Dynobob

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2003 LS650 (with
Supertrapp)

Posts: 634
Northern Virginia
Gender: male

Re: Explosion
Reply #6 - 08/17/06 at 05:30:35

ohms wrote on 12/31/69 at 16:00:08:

I normally use the choke to start and it starts very easily. But there was time when i would have to crank it for ages b4 it would start. Perhaps its too rich in the carb possibly? Undecided

Mine starts with little or no choke most the time. I've never had a bang starting or stopping. I do get just a little popping while riding.

I would think you're lean, not rich. 152.5 isn't very big with a Jardine and a K&N.

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Brewbrother

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Just lending a
helping hand.

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Re: Explosion
Reply #7 - 08/17/06 at 15:32:42

Dynobob wrote on 12/31/69 at 16:00:08:

Mine starts with little or no choke most the time. I've never had a bang starting or stopping. I do get just a little popping while riding.

I would think you're lean, not rich. 152.5 isn't very big with a Jardine and a K&N.

I did not know that the main jet had any effect on starting the bike. Doesn't the main jet control 3/4 to WOT?? I'd look to air leaks for a backfire on start up. Specifically the intake boots.

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Opportunities multiply as they are seized.
No spacer,60 pilot jet, 155 main jet, plug door, sportster muffler, k&n drop in, iridium plug, brake pedal mod,de-badged, Dunlops, bullet turn signals.

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Savage_Rob Serious Thumper Alliance Member Offline Mechanically Inclined Amateur Posts: 6972 Texas (Dallas area) Gender:	Re: Explosion Reply #8 - 08/18/06 at 06:23:21 When I had the stock Mikuni carb, mine ran best with a 152.5 main and a 55 pilot - but I had a MAC instead of a Jardine.
Back to top	1998\|MAC muffler\|ceramic coated header\|K&N air filter\|Amal Mk2 carb\|Odyssey battery\|iridium plug\|NC windshield\|Dunlop 491s\|Superbrace\|EBC brake rotor\|12.5" Progressive shocks\|Kuryakyn ISO grips IP Logged

PA KID Ex Member	Re: Explosion Reply #9 - 08/18/06 at 12:12:49 I have a jardine pipe with a 155 main an 55 pilot. Make sure your carb is tight to the head and gasket is in good shape.You did say you had it off alot.Might wanna check the plug to see what color it is.
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Trippah Serious Thumper Offline I ride, therefore I am. Posts: 2517 central Mass Gender:	Re: Explosion Reply #10 - 08/18/06 at 13:38:09 I'm really just guessing, but as I mentioned earlier, in fuel causes, too much fuel could cause a bang. Of course, electrical issues could be timing, or a predetonation- maybee the spark plug given the mods to the carb?? Please keep us posted, we wrench vicariously
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ohms

Ex Member

Re: Explosion
Reply #11 - 08/18/06 at 19:12:01

Well I havent done anything but im thinking it might be fuel related. I have noticed that the bike starts very easily without the choke. I have ridden it now for a few days and decided not to use the choke on startup, I figured if it gave problems then I would try the choke. So far no big bang. Maybe the choke was enriching things too much, thats just my guess im still learning. 8)

Thanks for the help everyone.

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