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-   Crazy-Awesome almost Dakar racers (950/990cc) (http://www.advrider.com/forums/forumdisplay.php?f=34)
-   -   990 SAS removal. (http://www.advrider.com/forums/showthread.php?t=885127)

rossguzzi 05-06-2013 10:02 PM

990 SAS removal.
 
Is it the same as the 950 removal ? Looking at the how to archives, it only outlines the 950 proceedure.

Head2Wind 05-06-2013 11:20 PM

Physically the 950 and 990 very similar as far as the blanking plates and intake manifold interfaces. The differences are how the air injection and captive evap systems are turned on/off. The 950 uses vacuum actuated valves controlled by intake manifold signal, where the 990 uses electro actuated valves controlled by the ECM. The 950 ECM doesn't pay attention to the vacuum systems, so disconnecting and eliminating it doesn't throw any system errors. The 990 SAS and evap system valves are controlled by the ECM and the ECM will throw error codes if the valves are removed..... So there are two options for modifying the SAS and evap systems..

1. leave the valves attached to the wire harness but remove the hoses and blank the heads and manifolds with the standard SAS blank plates and 6mm bolts.
2. Do the first option blanking/plugging but also cut the 2 SAS and Evap wire harnesses just short of the plug and solder in 2.2k ohm resistors between the two wires. This fakes the ECM into thinking that the electro valve is still present in the system and therefore does not know that it really is just a resistor.

rossguzzi 05-07-2013 12:30 AM

That makes sence. I am thinking (to help the on off throttle) to do this and the TuneECU map thing.
Thanks !

Apple Jam 05-07-2013 12:41 AM

So....since this SAS subject is up on the table...

I did my SAS removal at the same time I replaced some rather dirty fuel filters. I have noticed significant change for the worse in the famed jerky throttle at low revs. Especially annoying coming off 2-3k off-road.

I've ridden this bike through 50k miles and 2 other filter set changes, and I never remember it being this bad. But I never off-roaded so much as the last two years, so it could be my imagination, but......

Just a thought......I blamed the fresh fuel filters originally,...could this air injection be smoothing out throttle at low rpm? I mean, it's purpose is to heat the cats at idle/warmup....was this, just maybe, causing more backpressure and lowering power output at very low rpm?

Edit: 07 -990FI
Also, kinda curious.....What opens the reed valves on the heads, vacuum from exhaust, or pressure from the SAS pump?

rossguzzi 05-07-2013 01:00 AM

I am not sure. Others hopefully may chime in. But I am also concidering removing the additional butterflys. Good idea ?

Apple Jam 05-07-2013 01:11 AM

Quote:

Originally Posted by rossguzzi (Post 21349643)
I am not sure. Others hopefully may chime in. But I am also concidering removing the additional butterflys. Good idea ?

I thought I had a better one than what everyone was complaining about, or maybe they were wussies :evil

Now I'm looking at other options like secondary butterfly removal, oval replacements, Tune ECU.....or jmaybe ust putting the dirty fuel filters or the SAS back in :lol3
Don't really need all 100 ponies where I ride most these days. 80+ is juuust fiiiine with a smoother throttle :nod

Sure glad she's no thumper when I wanna hammer it, tho...

Head2Wind 05-07-2013 09:47 AM

The SAS is a passive (no forced pumping) system as far as the injection of air into the exhaust system, so it requires a pressure depression in the exhaust port to allow air to flow past the reed/check valve and into the port. When valve is activated and air is flowing into the port, this will make the exhaust appear more "lean" to the O2 sensors and the ECU "should" react with more fuel, which with these engines tends to mellow them out on the twitchness meter. These engines also tend to respond well to pulling back the timing a little at small/low TPS openings, which indirectly effects the AFRs that the O2 sensor sees (goes richer when less advance).......

You can read the many threads about tuning and using the TuneECU app, eliminating the 2nd throttle plates or modifying their action in the ECM. There are many opinions on how this affects the ridability of the bike and whether its good/bad. Generally people will maintain the secondary plates to soften the hit.

Two Moto Kiwis 05-07-2013 10:15 AM

On my 990 SMR I removed the second flies and it got notchier, put them back in and with Tune ECU disabled the O2's which made a huge difference to the rideability at low RPMs.

Was going to do the full tune ECU thing but ended up running out of time before our trip.

SAS etc I blanked off and I fitted the resistor per Head2wind which worked perfectly.

Apple Jam 05-07-2013 01:09 PM

Quote:

Originally Posted by Apple Jam (Post 21349614)
...could this (SAS) air injection be smoothing out throttle at low rpm?
I mean, it's purpose is to heat the cats at idle/warmup....
...was this, just maybe, causing more backpressure and lowering power output at very low rpm?

Edit: 07 -990FI
Also, kinda curious.....What opens the reed valves on the heads, vacuum from exhaust, or pressure from the SAS pump?

Quote:

Originally Posted by Head2Wind (Post 21351789)
The SAS is a passive (no forced pumping) system as far as the injection of air into the exhaust system, so it requires a pressure depression in the exhaust port to allow air to flow past the reed/check valve and into the port. When valve is activated and air is flowing into the port, this will make the exhaust appear more "lean" to the O2 sensors and the ECU "should" react with more fuel, which with these engines tends to mellow them out on the twitchness meter. These engines also tend to respond well to pulling back the timing a little at small/low TPS openings, which indirectly effects the AFRs that the O2 sensor sees (goes richer when less advance).......

You can read the many threads about tuning and using the TuneECU app, eliminating the 2nd throttle plates or modifying their action in the ECM. There are many opinions on how this affects the ridability of the bike and whether its good/bad. Generally people will maintain the secondary plates to soften the hit.

So my theory may have been *kind of-ish* correct !!
SAS might just go back in,,,hmmmm.
As I understand it, the only disadvantage is a mess of hoses and some decel popping that I had only very slightly with the Akros.

AWESOME technical response, H2W !!

rossguzzi 05-08-2013 12:45 AM

Quote:

Originally Posted by Head2Wind (Post 21349417)
Physically the 950 and 990 very similar as far as the blanking plates and intake manifold interfaces. The differences are how the air injection and captive evap systems are turned on/off. The 950 uses vacuum actuated valves controlled by intake manifold signal, where the 990 uses electro actuated valves controlled by the ECM. The 950 ECM doesn't pay attention to the vacuum systems, so disconnecting and eliminating it doesn't throw any system errors. The 990 SAS and evap system valves are controlled by the ECM and the ECM will throw error codes if the valves are removed..... So there are two options for modifying the SAS and evap systems..

1. leave the valves attached to the wire harness but remove the hoses and blank the heads and manifolds with the standard SAS blank plates and 6mm bolts.
2. Do the first option blanking/plugging but also cut the 2 SAS and Evap wire harnesses just short of the plug and solder in 2.2k ohm resistors between the two wires. This fakes the ECM into thinking that the electro valve is still present in the system and therefore does not know that it really is just a resistor.

When you say 'valves' can you tell me where they are? I fell a little dumb when operating on an unfamiliar bike. I`m sure that wont last long.

Hipster 05-08-2013 06:46 AM

Quote:

Originally Posted by Apple Jam (Post 21353349)
SAS might just go back in,,,hmmmm.

Has anyone else had negative affects from removing the SAS on their 990?

Head2Wind 05-08-2013 09:12 AM

Quote:

Originally Posted by rossguzzi (Post 21357818)
When you say 'valves' can you tell me where they are? I fell a little dumb when operating on an unfamiliar bike. I`m sure that wont last long.

there is one just forward of the airbox, it controls the evap systems. there is one just aft of the airbox (attaches to the back on tabs) that controls the SAS systems.

renogeorge 05-08-2013 08:44 PM

SAS Off???
 
I am coming off a 950 where I removed the SAS with no ill effects. I just acquired an '07 Adventure with 30k miles. With no service records or PO info, I am hurrying to ready it for an Alaska trip in July. I am planning a quick tank off/once over, checking/adjusting valves, new plugs, fuel filters and pump. I had planned on doing the SAS removal while I am in there.

For the short run, the emphasis will be on street riding. So far, I have been OK with the throttle response--might change when I get back and have time for more dirt.

I am also looking seriously at the 2 into 1 exhaust setup and foam filter/air box removal.

I am handy enough with the mechanical stuff and working through the inevitable issues you run into when making modifications.

But I am really wondering how far I should go with the mods keeping in mind I need to make them, sort them out and have the bike reliable by mid June.

Any advice??? Thanks in advance!

Head2Wind 05-08-2013 11:09 PM

removal of the SAS and evap is not going to directly cause any significant system failures and should some thing related to these modifications fail, the engine will still run, just will have EFI fault codes. I would say that it is worth the effort and risk to make these changes.

Adding in the removal/replacement of the OEM airbox with a foam filter assembly is adding risk, but not significant, provided the work can be performed well prior to the planned trip to perform some testing.

Personally.... for right or wrong.. and it has bit me sometimes.... I am working on my bike up to the night prior to leaving on a trip.

renogeorge 05-09-2013 09:02 PM

Thanks. I am getting mixed reads on the ECU re tune. If I do the filter and SAS removal, will I need a remap? I am thinking that's what I will do....


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