Not my sled but worked on it. Guy is seeing the knock light alot like almost every hard pull on 240,290 tune. Is this normal? If so whats recommended? Boost is too small to read at those speeds on gauge. Reason I am asking is my buddy with a cat has almost same issue. Every single time we have raced that was his excuse the last two years. I didnt believe him but saw it myself last weekend indicated on gauge after we did some friendly racing. You guys with tunes always have to run Octane Boost? If so what brand and what amount?
Bogus fuel? Does he have a 3Bar sensor in it?
Yes I believe that came with kit.
Could be but it happens so often in both cases.
I haven't seen knock once in 2 seasons running the 270 tune. I try to add Lucas octane boost in with any fuel that's been sitting in the sled any length of time.
Motorhead
TY 4 Stroke God
- Joined
- Apr 20, 2003
- Messages
- 2,090
- Location
- Augusta, Maine
- Country
- USA
- Snowmobile
- 2017 SW LTX-LE
- LOCATION
- Augusta ME
I do not believe that is normal.
2 of us running the same (this season 3 bar Max Spool 16 tune), one with smm other with sm.
Using 93 octane only so far because all gas stops had it.
Would like to try 91 and see if anything changes but most stations skip 91 and offer 93!! So 87, 89 or 93.
Not interested in having to bring a bottle octane booster for trail racing/riding. Been there and that was a hassle.
I ride very normal except for when the safe trail or road ahead beckons me. I really try and keep it safe as possible because I have no interest in harming others on the trail. Last ride we saw not one sled on the trails but did see 3 guys at the gas stop. Over 120 on the speedo was attainable dozens of times during the day.
“I don’t always drink boost, but when I did” local auto parts shops carry Lucas.
2 of us running the same (this season 3 bar Max Spool 16 tune), one with smm other with sm.
Using 93 octane only so far because all gas stops had it.
Would like to try 91 and see if anything changes but most stations skip 91 and offer 93!! So 87, 89 or 93.
Not interested in having to bring a bottle octane booster for trail racing/riding. Been there and that was a hassle.
I ride very normal except for when the safe trail or road ahead beckons me. I really try and keep it safe as possible because I have no interest in harming others on the trail. Last ride we saw not one sled on the trails but did see 3 guys at the gas stop. Over 120 on the speedo was attainable dozens of times during the day.
“I don’t always drink boost, but when I did” local auto parts shops carry Lucas.
number1kyster
TY 4 Stroke God
Someone asked a similar question on a group I am part of. They were running a high HP tune with a little race fuel and still seeing the knock light. TD Ben wrote this regarding the issue:
"Some sleds have knock sensors that are too sensitive this is one of them.
The more power a sled makes the more engine noise it creates . Higher HP maps will show more false knock than low power maps.
Try loosening the sensor and torquing it to spec first. Over overtorqued they will be more sensitive."
Sounds like at least in our area NW WI and UP MI Octane boost is going to be needed to avoid this. Lucas and Torco seem to be the best and most available. How much do you guys use every tankful?
Hammer70
GRIPNRIP
- Joined
- Sep 6, 2015
- Messages
- 824
- Location
- Niagara, Ontario.
- Country
- Canada
- Snowmobile
- 82SS440/96VMAX/02SRX/08APE/15SRVIPER/17SIDEWINDER
I used torco 8oz to full tank on my 290 tune no lights at all. On the 240 270 I have run 91 no lights. All the readings for what you want are on side of can.
Thank you. Will try this weekend and if it doesn't help will have to bring it in shop and see what's going on.
ClutchMaster
HUGE Member
- Joined
- Jan 18, 2016
- Messages
- 2,996
- Location
- tomahawk
- Country
- USA
- Snowmobile
- 2015 Viper 270 hurricane,
2002 Viper W/162 A.C. skid, SRX pipes &CDI, 780 BB
- LOCATION
- Wisconsin
Some have replaced the sensor and the problem has gone away. Could be the sensor or could be over tightened?
If you want too know if it’s false knock, dump 4-5 gallons of 110 octane in the tank. This will guarantee its false.
I’ve had good luck using locktight on the threads just a smidge past finger tight on my 4G63.
Motorhead
TY 4 Stroke God
- Joined
- Apr 20, 2003
- Messages
- 2,090
- Location
- Augusta, Maine
- Country
- USA
- Snowmobile
- 2017 SW LTX-LE
- LOCATION
- Augusta ME
Stock sensor?
Where is it located on the motor?
Where is it located on the motor?
Similar threads
