Knock sensor going off?

[flabbajabba]

Ok I've got a 09 xp with a 14 to 1 head and I mostly ride in the mountains. Decided to go for a rip around here (Edm) and the knock light came on right away? My guess is fuel? I had half a tank left and filled up at Husky with premium. Never had the light on before. I'm guessing drain the gas fill up with Shell premium. Is that enough? It ran last year same head no light. Its out at the lake so I don't really have access to race fuel. Just trying to go for a family ride for x-mas.

 

[maxwell]

get some 13.5 domes for riding around here.

also husky fuel is a nono from my experience

 

[revbyu]

14 to 1 in lower elevation will require the use of race fuel - i dont think 91 octane will be enough!

 

[maxwell]

that too

 

[flabbajabba]

14 to 1 in lower elevation will require the use of race fuel - i dont think 91 octane will be enough!

Kind of what I thought. I just wanted to make sure before I tell my friend (its his sled) to go out and buy a jug of VP not cheap $$$. That being said, 25% race be about the right amount? This sled very rarely runs down here so I think the race fuel is probably the best solution. I know he will not want to change his head/domes just for here.

 

[DaveB]

I run 14:1 (last 3 sleds) ....50/50 AV gas/91 Shell premium around here....25/75 in Revy (take it easy down low). AV gas is only 1.30 a litre....

Whos head? RKT runs TIGHT squish and needs to be lean to run right....which also requires more octane to be safe.

 

[flabbajabba]

I run 14:1 (last 3 sleds) ....50/50 AV gas/91 Shell premium around here....25/75 in Revy (take it easy down low). AV gas is only 1.30 a litre....

Whos head? RKT runs TIGHT squish and needs to be lean to run right....which also requires more octane to be safe.

Terra Alps head. Where is the easiest place to get AV?

Now for the fun question if the light doesn't come on with just premium is it safe? (At altitude or down low?) I'm asking these questions for two reasons trying to help a buddy out while he's out of town (light issuses) and I'm going to be buying a head very soon and trying to pick my domes? If I went 13.5 I'd be good for pump? I've never ran my sled here, mostly Mcbride Vale and Revy.

 

[DaveB]

With an RKT head, I ran the mixtures above....I pulled 'er apart this past summer and had evidence of deto (pin-prick holes around the piston edge). The deto light never flashed once. I run an Engine Tech head now (8 thou more clearance on the squish) with the same mixture....hopefully I don't show deto next tear-down. I was able to jet up a couple of sizes and it still runs nice with this head. (The Terra head is supposedly an ET copy, so you should be fine)

 

[c3burn]

I used to buy my race fuel at AFD on Sherwood Park Freeway and 17st. It has been a while since I have be there so I would phone first.

 

[flabbajabba]

Thank you to all it turns out it was a 13.5 to 1 head and Shell premium and octain boost did the trick no more Knock light. Pretty sure this will be the last time Husky fuel will be in this sled!

 

[maxwell]

husky + mohawk = bad news...IMO