holm0069
New member
Bought an 04 SX Viper Mountain just after X-mas. DCS light was coming on. Sled only has 500kms on it so I took it into a Yamaha dealer to have the carbs and power valves cleaned and everything checked over. Issue not solved.......running high octane in sled also. Anyone have any idea what the f*ck is going on here. Haven't been able to drive it because I don't want to cause any damage. Once sled is warmed up and I hit the throttle the light flashes 6 times slow and then continuously fast as long as the throttle is down. Any help would be awesome.......thanks.
let me ask a couple questions:
Is the sled bone stock?, meaning no aftermarket exhaust, no air box mods, no add ons?
what fuel are you running in it?
I have a few ideas but need to know this first before I can help further.
Is the sled bone stock?, meaning no aftermarket exhaust, no air box mods, no add ons?
what fuel are you running in it?
I have a few ideas but need to know this first before I can help further.
holm0069
New member
Hey bud,
Viper is 2004 Mountain. Completely stock. I've drained tank and ran high octane in it. Don't know what else to tell you. Carb's and powervalve's professionally cleaned and serviced. Its been to two Yamaha dealerships and both said it was clean and ready to go and shouldn't have any issues. Get it home and once its warmed up and I squeeze the throttle the DCS light flashes. Been trying to research the hell out of it but not having any luck. Dealerships also not sure what to tell me. Would love some help.....thanks.
Viper is 2004 Mountain. Completely stock. I've drained tank and ran high octane in it. Don't know what else to tell you. Carb's and powervalve's professionally cleaned and serviced. Its been to two Yamaha dealerships and both said it was clean and ready to go and shouldn't have any issues. Get it home and once its warmed up and I squeeze the throttle the DCS light flashes. Been trying to research the hell out of it but not having any luck. Dealerships also not sure what to tell me. Would love some help.....thanks.
holm0069
New member
mrviper Ive been looking around and it seems your the go to guy for this sort of thing. The high octane fuel at the stations in my area is 91 octane. Is this my problem? I just don't get why the dealerships haven't heard of this before. They make it like mine is unique because I'm having these issues. Appreciate the help.
super1c
Super Moderator
That dcs can be a PIA. I had some trouble with it running pipes and now that stock i get the light any time i cant get good gas. Just this weekend we were out in the middle of now where and had to fill up with 89. The light would blip any time i got on the gas hard. Just had to baby it home. Most of the time i use 93 and octain boost. I alway run 93 but somtimes you have to use what ya have. I made sure my other vipers without the dcs (wifes and daughter) rode calm and safe home. Im sure raising the needles and opticool saved us.
Chris hit on most of this in his post but really 91 octane is pretty low, all in all its simply too low as thats why the dcs light is coming on. More octane will make the dcs not bother you. The higher the octane is the richer the sled runs WITHOUT touching the jetting. Octane is the fuels ability to not burn, so it slows down the flamefront and burns not as violent.
So.. you have a couple options to solve the problem.
1.) use higher octane fuel then 91, like 93-94. If this is not feasable because of your location , you can always get some race gas and mix a little bit of that to a tank of the 91, this will raise the octane of the whole tank. I am talking about 1-2 gallons of racing gas say like 104+ octane stuff to the rest 91.
2.) if thats not possible or you dont want to be bothered with it, you have a other option to make the sled run richer via the jetting set up, will yield off detonation and make the light not bother you.
First, raise the carb needles to 3.5, this is the 4th groove down from top of the needle and then theres 2 small plastic shims, 1 shim on top of the clip, 1 shim on bottom of the clip. You can also install 157.5 mains in the carbs. This will richen it up and "cool" off the pistons with more fuel and hence make the detonation not occur. If all your going to use is 91 this is your only real way to go.
The vipers were set up lean from the factory, and they have higher compression in the mag and center cylinders, along with a cdi box with lots of ignition timing. Todays low quality fuel is just not cutting it. these problems were not very noticeable until the last few years as the fuel has gotten cheaper quality(they dont mind still charging us for the higher prices though...
).
So.. you have a couple options to solve the problem.
1.) use higher octane fuel then 91, like 93-94. If this is not feasable because of your location , you can always get some race gas and mix a little bit of that to a tank of the 91, this will raise the octane of the whole tank. I am talking about 1-2 gallons of racing gas say like 104+ octane stuff to the rest 91.
2.) if thats not possible or you dont want to be bothered with it, you have a other option to make the sled run richer via the jetting set up, will yield off detonation and make the light not bother you.
First, raise the carb needles to 3.5, this is the 4th groove down from top of the needle and then theres 2 small plastic shims, 1 shim on top of the clip, 1 shim on bottom of the clip. You can also install 157.5 mains in the carbs. This will richen it up and "cool" off the pistons with more fuel and hence make the detonation not occur. If all your going to use is 91 this is your only real way to go.
The vipers were set up lean from the factory, and they have higher compression in the mag and center cylinders, along with a cdi box with lots of ignition timing. Todays low quality fuel is just not cutting it. these problems were not very noticeable until the last few years as the fuel has gotten cheaper quality(they dont mind still charging us for the higher prices though...
).holm0069
New member
I'll try boosting the octane in it and go from there I guess. Then maybe turn to the jetting if that doesn't work.
Dealership phoned me back today and said they spoke to Yamaha and they said there was issues with the wiring harness under the motor with the Viper's and I should check that. They also hinted at a bad sensor but to me the sensor works fine it is just telling me something.
I appreciate all the help fellas and I'll keep you posted. Thanks for now.
Dealership phoned me back today and said they spoke to Yamaha and they said there was issues with the wiring harness under the motor with the Viper's and I should check that. They also hinted at a bad sensor but to me the sensor works fine it is just telling me something.
I appreciate all the help fellas and I'll keep you posted. Thanks for now.
holm0069 said:
They may have been talking about the TP sensor which IIRC was recalled on the R1 street bike but was also used on the SRX ('01-'02 MY).
Sideshow Bob had done some testing on his '02 SRX which found an erratic output which had an affect on ignition timing. He had a persistant DCS and had gone after the crank, knock sensor and other items and I believe he corrected it with a new TPS.
Again, IIRC the issue would not show up unless he monitored the TPS signal return with the engine running while also watching spark advance. Search sideshowbob and TPS and you should find the lenthy thread.
Not sure when the recall was released but your '04 may be a candidate.
J_hubbs
New member
I have an 04 with DCS. I raised my needle to the 4th notch with no shims below. Last week I ran it in the UP in 0 deg weather. I had the DCS flashing if I held it in the 7200 rpm range. I had a few of the mini octane boost bottles (made to treat a motorcycle tank 5gal) it didnt help much. We stopped at a fuel station with 100% gasoline. The DCS didnt flash on that tank. I will be raising the needles again.
When the DCS light flashes it signals it has detected engine detonation, the CDI will then begin retarding the timing to protect your engine. If you do not elliminate the detonation by releasing the throttle it will continue reducing the timing until sled will barely run. This all resets automatically when sled is returned to idle. It is a GREAT system...when it works properly.
Being that this sled is a Mountain version it may be jetted for higher altitude then the 570` elevation in the Ottawa area.
The DCS system is telling you the sled is too lean or has too much timing advance for the octane of fuel its using.
Items to check to elliminate nuissance DCS issues.
-ensure highest octane fuel used
-ensure carbs are clean
-ensure stock jetting or richer settings used...raise needle settings as advised
-ensure TPS...throttle position sensor..is adjusted and functioning properly
With todays fuel and the way the Vipers ignition timing and staggered compression works you may have to use richer jetting, especially on the needle settings, then Yamaha ever anticipated on these sleds.
I had random DCS issues on my 2002 SRX that I finally solved with a new TPS and have had no DCS issues since.
JM.02c
Bob
Being that this sled is a Mountain version it may be jetted for higher altitude then the 570` elevation in the Ottawa area.
The DCS system is telling you the sled is too lean or has too much timing advance for the octane of fuel its using.
Items to check to elliminate nuissance DCS issues.
-ensure highest octane fuel used
-ensure carbs are clean
-ensure stock jetting or richer settings used...raise needle settings as advised
-ensure TPS...throttle position sensor..is adjusted and functioning properly
With todays fuel and the way the Vipers ignition timing and staggered compression works you may have to use richer jetting, especially on the needle settings, then Yamaha ever anticipated on these sleds.
I had random DCS issues on my 2002 SRX that I finally solved with a new TPS and have had no DCS issues since.
JM.02c
Bob
staggs65
Moderator
I've got a nagging DCS issue I've been trying to solve too. but this one is piped with an aftermarket head. been chasing my tail with it. let us know how you make out holm
My 2002 SRX is ported, power inc pipes, Peak heads[12.2:1], 2 degree timing advance key, TMX 38 carbs, reeds ect and I have been able to use the DCS system effectively so it can be done.