SuzukiSavage.com - The big Pow when you shut off?

Sassy Savage

YaBB Newbies

Offline

This girl can hold
her own...

Posts: 16
Edmonton, Alberta, Canada
Gender: female

The big Pow when you shut off?
06/12/14 at 10:02:06

Hi Everyone,

I need your beautiful knowledge... Sooo I keep being told that... All the savage's make the BIG POW when you turn off the bike and that there is nothing you can do to change this... I've been told it's due to the piston's taking that last big swing of compression. Please tell me that is not the truth and what I can do? It is so embarrassing pulling up and shutting your bike off to have this load big pow Sad

Any help would be great. Thank you

Back to top

1986 Savage LS650, Bike is mint, no mods,Edmonton, AB Canada

IP Logged

HAPPYDAN Senior Member Offline SuzukiSavage.com Rocks! Posts: 270	Re: The big Pow when you shut off? Reply #1 - 06/12/14 at 10:15:21 Once that pesky brass-plugged air-mix screw (I think that's what it's called) is properly adjusted (usually2-3 turns out), then just pull out the choke, Chugga-Chugga-Chugga, switch off and no POW!
Back to top	IP Logged

Dave

YaBB Moderator
ModSquad

Offline

SuzukiSavage.com
Rocks!

Posts: 18099
Camp Springs, Kentucky
Gender: male

Re: The big Pow when you shut off?
Reply #2 - 06/12/14 at 10:15:32

When you turn off the ignition, the engine was turning at 1,000 - 1,100 rpm and it continues to pull fuel and air from the carb while it is slowing down and coming to a stop. This fuel and air is not ignited in the cylinder as the ignition is switched off....so the fuel/air mix is pumped out the exhaust valves and into the header and muffler. The header and muffer are still hot....and the unburned fuel/air mix will be warmed up by the hot exhaust....and if the fuel/air mixture reaches the flash point...it is ignited. The result can be a pleasant little "poof" that makes you kinda' snicker - or it can be a "POW" that makes folks duck for cover.

The difference in the sound level can be affected by a combination of idle speed and fuel mixture. The faster the engine is turning the more fuel and air is pumped into the exhaust - and the leaner the mixture the the bigger the bang.

What has been done to your carb? Has it had any jet changes, has the plug over the idle mixture screw been removed?

My bike is jetted really well, and on rare occasion I get a tiny little "pfft" after I turn the bike off. In order for this to happen I have to shut if off rather quicklly after riding at speed. If I spend anytime idlling or riding across a parking lot, the bike does not make a single sound when turned off.

Dave

Back to top

Someday I will be old......But not today!

IP Logged

nickthe_human

Full Member

Offline

Posts: 172
Arkansas
Gender: male

Re: The big Pow when you shut off?
Reply #3 - 06/12/14 at 10:19:50

what Dave said.

Mine doesn't all the time. Most of the time if I just stop and turn it off, I get a soft whoomphff. And at night sometimes if its big enough, a blue flame shoots out Cool

But the choke suggestion is nice. I use it when I pull under roofs at banks and gas stations just to be nice and not scare anybody.

Also, if you let it idle for just a few more seconds before shutdown, it reduces the sound considerably.

Back to top

2005 S40

IP Logged

Sassy Savage

YaBB Newbies

Offline

This girl can hold
her own...

Posts: 16
Edmonton, Alberta, Canada
Gender: female

Re: The big Pow when you shut off?
Reply #4 - 06/12/14 at 10:35:39

Hi Dave,

What has been done to the carb? Nothing as far as I know... I do not believe any jet changes, and I don't believe the plug over the idle mixture screw been removed.

I hate to admit this, but I am not mechanically inclined. This is my first bike and I was told that nothing was done to it other than regular maintenance....

What is this jet change you mention?

Back to top

1986 Savage LS650, Bike is mint, no mods,Edmonton, AB Canada

IP Logged

1st2know

Senior Member

Offline

Currently between
Savages

Posts: 295
Seattle, WA
Gender: male

Re: The big Pow when you shut off?
Reply #5 - 06/12/14 at 10:35:53

Stock petcock?
The vacuum line from the right side of the carb to the petcock can develop small holes from the throttle body banging the hose against the head. The small holes allow additional air in to the fuel air mixture, causing the motor to run lean.

Loud backfire ("Big bang with a flash") is a symptom of this condition.
The test, and fix are both simple:
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1251932429/1

I wouldn't start tuning and modifying the carb with a stock petcock, it so troublesome, it's hard to isolate where problems are coming from.

Back to top

Kaw VN1700, V-Strom 650, Coal powered Chevy Spark.

IP Logged

Sassy Savage YaBB Newbies Offline This girl can hold her own... Posts: 16 Edmonton, Alberta, Canada Gender:	Re: The big Pow when you shut off? Reply #6 - 06/12/14 at 10:37:34 OMG Nick blue flames?? nuts I would die if that happened... lol
Back to top	1986 Savage LS650, Bike is mint, no mods,Edmonton, AB Canada IP Logged

Sassy Savage YaBB Newbies Offline This girl can hold her own... Posts: 16 Edmonton, Alberta, Canada Gender:	Re: The big Pow when you shut off? Reply #7 - 06/12/14 at 10:48:41 Yes I have a stock petcock... hmmm interesting, I would have never thought this would cause a problem.. Thanks I'll try to do the test
Back to top	1986 Savage LS650, Bike is mint, no mods,Edmonton, AB Canada IP Logged

Sassy Savage YaBB Newbies Offline This girl can hold her own... Posts: 16 Edmonton, Alberta, Canada Gender:	Re: The big Pow when you shut off? Reply #8 - 06/12/14 at 10:50:30 HAPPYDAN... What's the " pesky brass-plugged air-mix screw " you speak off? sorry for the dumb question... but where is it?
Back to top	1986 Savage LS650, Bike is mint, no mods,Edmonton, AB Canada IP Logged

1st2know Senior Member Offline Currently between Savages Posts: 295 Seattle, WA Gender:	Re: The big Pow when you shut off? Reply #9 - 06/12/14 at 11:10:14 Idle mixture screw plug removal: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1221818822 I would think that a 1986 would already have its plug removed by now. It would be interesting if was still there. Here's a site search tip - in google do this: site:suzukisavage.com idle mixture screw
Back to top	Kaw VN1700, V-Strom 650, Coal powered Chevy Spark. IP Logged

Dave

YaBB Moderator
ModSquad

Offline

SuzukiSavage.com
Rocks!

Posts: 18099
Camp Springs, Kentucky
Gender: male

Re: The big Pow when you shut off?
Reply #10 - 06/12/14 at 11:37:05

From the factory, the bike is jetted somewhat lean to provide an engine that satisfies the EPA, and the idle fuel mix screw has a brass plug over the adjustment so that you don't fuss with (improve) it. Jet changes can also provide for a mixture that allows a better running engine....and less noise in the form of pops and booms.

Can you do this yourself? Possibly....we do have "how to" threads in the Tech Section that you can review.

Dave

Back to top

Someday I will be old......But not today!

IP Logged

Sassy Savage YaBB Newbies Offline This girl can hold her own... Posts: 16 Edmonton, Alberta, Canada Gender:	Re: The big Pow when you shut off? Reply #11 - 06/12/14 at 12:36:45 Thank you for all the great information... Now I'm going to go home and try all this out... Keep you posted on progress! You are all so wonderful!
Back to top	1986 Savage LS650, Bike is mint, no mods,Edmonton, AB Canada IP Logged

Serowbot YaBB Moderator ModSquad Offline OK.... so what's the speed of dark? Posts: 28660 Tucson Az Gender:	Re: The big Pow when you shut off? Reply #12 - 06/12/14 at 13:11:06 Before trying anything mechanical,... try just letting the bike idle for 10 seconds before shutting off... That may solve the "Pow" problem by itself... Worth a try?... ...
Back to top	Ludicrous Speed !... ... ... IP Logged

Fishbulb Ex Member	Re: The big Pow when you shut off? Reply #13 - 06/12/14 at 13:25:47 Factory jetting, filter and muffler around sea level-ish. I come to a stop, pull the choke out and then hit the kill switch. No pop, bang, or puff anymore.
Back to top	IP Logged

verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28886 L.A. California Gender:	Re: The big Pow when you shut off? Reply #14 - 06/12/14 at 13:28:28 And fattening up the idle mixture screw an 1/8 to a 1/4 turn will do it to.
Back to top	Versey's Place Tech Section Index IP Logged

Poll
Question: The big Pow when you shut off?
True 11 (52.3%) False 10 (47.6%) Total votes: 21 « Created by: Sassy Savage on: 06/12/14 at 10:02:06 »