SuzukiSavage.com - Backfire before and after a Dyna Swap

marioivargas

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Backfire before and after a Dyna Swap
02/06/12 at 22:39:35

So I finally got my Dyna and the SAVAGE sounds a lot better without the atomic cricket and a lower rumble. I checkerd with a camp lighter and found there's no air leaks anywhere but I'm getting backfire. What should my diagnostics procedure be to find the issue.

I hear I should first start with cleaning the air filter and then perhaps rejetting?

Any good links to these procedures?

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LANCER Serious Thumper Alliance Member Offline Savage Beast Performance Parts Posts: 10689 Oklahoma Gender:	Re: Backfire before and after a Dyna Swap Reply #1 - 02/07/12 at 01:55:51 Look for "Carb tuning" in the Tech section
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Bubba Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 956 Denver, CO Gender:	Re: Backfire before and after a Dyna Swap Reply #2 - 02/07/12 at 06:10:44 yep, rejet...you'll have to experiment with different jets so replace the carb bolts with SS allen heads for ease of access. May have to fiddle with the air mix screw too. Have fun and be patient!
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justin_o_guy2

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Re: Backfire before and after a Dyna Swap
Reply #3 - 02/07/12 at 06:51:30

If your air mix screw isnt uncovered yet, do be ever so careflu with the drillbit. A piece of tape wrapped several times a hair back from where the taper stops & the full diameter of the bit starts will do it, figure out what you have around for a screw to pull the cap out with, drill a small enough hole to let the screw Bite before it hits the adjuster screw. That thing is way soft,, its brass.

Using a small flatblade, & just using fingertips, screw it in & count the turns, so if things dont work well you can at least get back to Square One. Closing it tight = messin it up, so, be gentle. Opening it too far releases pressure on the spring, making it possible for vibration to cause it to loosen & fall out, or so Ive heard, I havent seen it, but, common thinking on it is, over 3 turns out isnt a good idea. If I needed to go more, I would, but Id get a spring off a ball point pen & put in the mix,
Someone else may have another reason for not going more than 3 turns.

I didnt like the way it worked out trying to set that in the garage, its pretty fidgety & a small adjustment makes a pretty big change, so, I went for a ride & adjusted in tiny increments at stop lites.

I think you made a good choice on the muffler. Congrats on the NO Leak installation.

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Dutchmen YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 15	Re: Backfire before and after a Dyna Swap Reply #4 - 02/07/12 at 08:16:00 I put a Jardine w/a dyno jet kit and my still pops. It is just a common thing with this engine.
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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28905 L.A. California Gender:	Re: Backfire before and after a Dyna Swap Reply #5 - 02/07/12 at 08:32:14 The more open the back end of a muff is the more likely it will backfire. Thumpers generate a pretty strong puff of exhaust, and this causes a pretty strong return flow back into the muff. If there is any unburnt fuel hanging around... it won't be for long... can you say KERPOW!!!?
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Serowbot YaBB Moderator ModSquad Offline OK.... so what's the speed of dark? Posts: 28850 Tucson Az Gender:	Re: Backfire before and after a Dyna Swap Reply #6 - 02/07/12 at 08:59:40 Wuffle, blat, pops.. on decel are okay and normal... Kerpow's (gunshot cracks) are a problem and should be tuned out... usually by adjusting the pilot circuit or idle mix... sometimes just raising the idle speed a little helps...
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Routy

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Re: Backfire before and after a Dyna Swap
Reply #7 - 02/08/12 at 05:31:54

Serowbot wrote on 02/07/12 at 08:59:40:

Wuffle, blat, pops.. on decel are okay and normal...
Kerpow's (gunshot cracks) are a problem and should be tuned out... usually by adjusting the pilot circuit or idle mix... sometimes just raising the idle speed a little helps...

Many have gotten into trouble hackin the carb trying to get rid of the backfire. Backfire to a point is normal,.....even Suzuki will not warranty a backfire issue,......because it is not a real problem,....just an issue that can be controlled w/ throttle action.

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Rich
'07 S40 Blvd stocker, except drilled OEM exhaust and white spacer mod...1/2 (.055)

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Dutchmen YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 15	Re: Backfire before and after a Dyna Swap Reply #8 - 02/08/12 at 08:09:06 Mine didn't backfire that much w/stock setup, but was underpowered and too quite. Probably was running too lean. Installed the Jardene and dyno jet kit and it made it worse, but idleing the carb. up higher seems to help.
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650krc

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Re: Backfire before and after a Dyna Swap
Reply #9 - 02/08/12 at 10:29:16

Hello this is first response to this forum since I am new to the ls650 world. I have found this is one of the best post and easiest solution to the backfire issue. bruceclarkemexico.tripod.com/ls650.htm happy riding and I am looking forward to next weeks weather in Cincy for it will be in the 50's and dry great riding weather. Wink

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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28905 L.A. California Gender:	Re: Backfire before and after a Dyna Swap Reply #10 - 02/08/12 at 10:42:13 bad link
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Savage_Rob Serious Thumper Alliance Member Offline Mechanically Inclined Amateur Posts: 6972 Texas (Dallas area) Gender:	Re: Backfire before and after a Dyna Swap Reply #11 - 02/08/12 at 11:54:04 verslagen1 wrote on 02/08/12 at 10:42:13: bad link Worked for me. Try it this way: Click Me
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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28905 L.A. California Gender:	Re: Backfire before and after a Dyna Swap Reply #12 - 02/08/12 at 13:17:05 thx
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Routy Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 2280 Winston Oregon Gender:	Re: Backfire before and after a Dyna Swap Reply #13 - 02/08/12 at 17:07:53 verslagen1 wrote on 02/08/12 at 10:42:13: bad link It really is a bad link. Just throw the spacer away ?? In most cases, that is terrible advice. Like I said, many have gotten in real trouble hacking carbs, and still end up w/ the backfire.
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Savage_Rob

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Re: Backfire before and after a Dyna Swap
Reply #14 - 02/09/12 at 06:14:02

Routy wrote on 02/08/12 at 17:07:53:

verslagen1 wrote on 02/08/12 at 10:42:13:

bad link

It really is a bad link.
Just throw the spacer away ?? In most cases, that is terrible advice.
Like I said, many have gotten in real trouble hacking carbs, and still end up w/ the backfire.

It's been a while (I've been using an Amal Mk2 for years) but don't most folks either file it down or replace it with thinner version?

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