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Discussion Starter · #1 ·
Recently made two changes to my M109. First drilled 2 baffle plates out of each exhaust pipe (slightly better sound, with no noticeable change in performance just after) Within a week and approx. 200 miles, I added the JSD-3M and now am experiencing backfire on decelleration. Am I running lean, and if so is there a "non-tuner" solution. I don't know a lot about mapping, power commander, etc. and I'm not really looking for something that requires a lot of tweeking. Is there an average Joe solution to keep the modifications I have made? Am I harming the motor by riding it before a solution is determined?

As an aside the JSD-3M was a noticable change in performance below 4000 rpm. No more sluggish low rpm takeoff. No significant change in idle speed was noticed.

Thanks in advance for any advice anyone may have. This site has been invaluable to me so far.
 

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It may not be related to your mods.  Have you checked torque on your exhaust pipes since you bought the bike?  It's not unusual to have to torque new pipes once or twice and a small air leak anywhere in the system might cause your decel popping.  It's worth a check.
Jer
 

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What you did added to the already lean factory settings. I have a FI200 and it is easy to install and udjust. Too lean of a condition can also ruin your engine and burn holes in your pistons. Good Luck.
 

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One more thought. If the JSD3 mod was the simple plugin variety, unplug it ,and try bike without to try to isolate problem.
Jer
 

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The JSD is removing ignition retard, it does not adjust fuel. Does not do it on the M109, or any other F/I Suzuki.

Most anytime that you change intake/exhaust you need to adjust the a/f..... popping is most often seen associated with installing a new exhaust and "clamping" off the pair hose from the airbox fixes that problem.
 

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Discussion Starter · #6 ·
JSD-3M does not seem to cause the backfiring as it will still do it with JSD disconnected.... will try torquing the exhaust as suggested, and curious about jeff's suggestion to clamp off the airbox hose to richen things. Any guidance in this area would be appreciated. I suspect that opening the exhaust has created the ocassional backfire issue I have.

Thanks for all the help and great information.
 

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ARCON said:
JSD-3M does not seem to cause the backfiring as it will still do it with JSD disconnected.... will try torquing the exhaust as suggested, and curious about jeff's suggestion to clamp off the airbox hose to richen things. Any guidance in this area would be appreciated. I suspect that opening the exhaust has created the ocassional backfire issue I have.

Thanks for all the help and great information.
Yes. From the airbox you should have an exit that goes to the piar valve (then one line to each cyl head), for testing just clamp off the exit from the airbox (with a set of hemostats) and you will know real quick. This is the same exact thing that we do when putting a bike on the dyno, else the a/f reading would be off.
 

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I'm just curious. I assumed when you said you drilled two baffle plates in each pipe that you just raised the bike on a hoist or something amd did all your work from the back of the bike. You didn't loosen or remove the pipes by undoing the bolts where the exhaust are connected to the cylinders, or the clamps where the mufflers are connected to the header system , did you?
Jer

ARCON said:
Recently made two changes to my M109. First drilled 2 baffle plates out of each exhaust pipe (slightly better sound, with no noticeable change in performance just after) Within a week and approx. 200 miles, I added the JSD-3M and now am experiencing backfire on decelleration. Am I running lean, and if so is there a "non-tuner" solution. I don't know a lot about mapping, power commander, etc. and I'm not really looking for something that requires a lot of tweeking. Is there an average Joe solution to keep the modifications I have made? Am I harming the motor by riding it before a solution is determined?

As an aside the JSD-3M was a noticable change in performance below 4000 rpm. No more sluggish low rpm takeoff. No significant change in idle speed was noticed.

Thanks in advance for any advice anyone may have. This site has been invaluable to me so far.
 
G

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Popping on decel as I understand it is related to unburned fuel in the exhaust burning later in the timing cycle, so not necessarily lean.
 

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Discussion Starter · #10 ·
Jer: I didn't remove or loosen any of the exhaust system components when drilling the baffles.... simply jacked the bike up and went at it through the end of the pipes with the recommended hole saw and 12" extension.

Jeff: Thanks for the instruction... I will try to tackle this one soon and may have more questions to post. By the way, great work on the JSD-3M. Very satisfied with the results.
 
G

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on a completley stock bike does it come lean from the factory? & if you mess with the air box (more air flowing filters) does this make it more lean ? hence poping thru air box when cold
 

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joet said:
on a completley stock bike does it come lean from the factory? & if you mess with the air box (more air flowing filters) does this make it more lean ? hence poping thru air box when cold
I would say yes to both questions......and since Suzuki does not make a "closed loop" f/i system you either live with it or buy some tuning box.
 
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jeffw said:
I would say yes to both questions......and since Suzuki does not make a "closed loop" f/i system you either live with it or buy some tuning box.
This Bike is not lean with the air box open. Here is the proof. And when we tried to close the fresh air intake on the system the bike stalls.



These numbers are a stock bike the the stock air cleaner assembly removed.

Jeff what area of the country are you in? Do you have a Dyno, could you do the same test so we could compare the Dyno Numbers like for like.

TAZ
 

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Well, looking at your a/f ratio, up to 5000 rpm, it is a little lean.... target 13.1:1 for most bikes (and yes this does varry, but is a good starting point).
Notice around 4k, it goes a bit lean.... at the same time you get a little drop in hp.


I am now in Idaho, my dyno days have now passed. :( I did dyno runs for the last 5 or so years for Olathe Suzuki (metro Kansas City) back when I was supporting a AMA Superbike racer.


Damn nice bike you have... 120 rwhp :bigthumbsup: :bigthumbsup: :bigthumbsup:
 
G

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I know we need an power commander to add fuel in the end and take it out in the beginning. I wish they would respond to our communication.
 

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I hope we don't get too far from Arcon's original problem.
You may not really have a problem Arcon, but your opened up exhaust may just allow you to hear the decel noise that was muffled better before.
Check the ends of your pipes and see if they look like a lean condition, or better yet, do a plug check and see if they look tan (fine), white (lean), or darkish (rich).
I suspect you don't really have a problem but's it's nice to know for sure.
If you've been following the PAIR valve discussion, I think you can get an idea what's going on. As soon as someone develops some removal replacement plates and we get some guidance, I think removing your Pair valve will probably eliminate your decel popping.
Jer
 

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My bike is completely stock. I get back firing most of the time when down shifting. Whats the torque setting for the exhaust pipes?
 
G

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jeffw said:
Well, looking at your a/f ratio, up to 5000 rpm, it is a little lean.... target 13.1:1 for most bikes (and yes this does varry, but is a good starting point).
Notice around 4k, it goes a bit lean.... at the same time you get a little drop in hp.

I am now in Idaho, my dyno days have now passed. :( I did dyno runs for the last 5 or so years for Olathe Suzuki (metro Kansas City) back when I was supporting a AMA Superbike racer.

Damn nice bike you have... 120 rwhp :bigthumbsup: :bigthumbsup: :bigthumbsup:
Hey Bro I will be heading to Michigan to pick up my Dad and his VTX to go to the Dragon, I would like to have lunch when I come through. If you are interested PM me.

TAZ
 

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raw_taz said:
Popping on decel as I understand it is related to unburned fuel in the exhaust burning later in the timing cycle, so not necessarily lean.
I agree! With the stock timing (retarded) I would venture to say the decel popping would be more prevalent. With the JSD installed I would think it would be less noticeable but not neccessarily.

Changing the timing as the JSD does (advancing), the engine can run a little leaner and hotter because the fuel is being burnt more efficiently, whereas the stock retarded timing can cause extra unburnt fuel to pass through the engine and possibly cause more popping.

That said, all engines pop on de-acceleration but you usually don't hear it unless the exhaust is opened or loud. So, like one other poster suggested, you are probably just hearing the popping because you've opened up your exhaust and it is more noticeable now. Plug your exhaust back up and I'll bet you won't hear it as much.

The Harley boys love the sound of the exhaust popping, that's why most of them use straight thru pipes. Personally I love the stock sound of my 109 and do not want to draw more attention than it already gets, especially from the guys who wear black and white! ((( ; Loud exhaust may sound good to some, but the keepers of the peace can hear it blocks away and know what you are up to even if they can't see you! ))) :

As for me, the quieter the better!! ( :

EFE M109
 
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