650/X-2 650sx timing

[waterbox]

Hey just Installed a new stator on my 650sx. I lined up the notch on the stator plate with the one on the case (I assume thats stock timing) anyway I hear advancing it will pump a little more power out of it? What is a "safe" amount to advance it? thanks

 

[Vumad]

You can advance it as far as you want, but advancing it can cause detonation at high RPM. If you want to hold it WOT for a while, leave it where it is. If all you want to do is putt around at half throttle, then have short 10 second blips of WOT, then let back off, you can advance it all the way. Advancing it all the way is only for getting the most bottom end, and cannot be used to gain top end performance. Actually, advancing that far removes your ability to ride WOT as you will cause motor damage if you hold WOT for more than say 30 seconds.

 

[waterbox]

Exactly what I was looking for thanks vumad. Is there a happy medium as far as getting the best of both worlds?

 

[Vumad]

I don't know. I liked holding my SX WOT so I left it stock. I don't know where the medium is. I would imagine that you would be able to see the detonation in the plugs as it would probably appear lean. Check the plugs and be careful. 93 octane may help prevent detonation some. Don't push it.

 

[Snivilous]

What if you run race gas or something? If you don't have predetonation does it still hurt the motor?

 

[waterbox]

Running race gas would definitely decrease detonation, but that stuff is expensive. I'm just wondering because the previous owner of my ski had the timing all the way up, so when I put in the new stator I put it back to stock and lost a little bit of power. Most the time I'm just cruising hitting wakes, but every now and then I'll get a wild hair and pin it. Will you "feel" the motor detonating at WOT?

 

[mx21]

Running race gas would definitely decrease detonation, but that stuff is expensive. I'm just wondering because the previous owner of my ski had the timing all the way up, so when I put in the new stator I put it back to stock and lost a little bit of power. Most the time I'm just cruising hitting wakes, but every now and then I'll get a wild hair and pin it. Will you "feel" the motor detonating at WOT?

It's still expensive but you can also mix it 50/50 with premium pump gas to help prevent detonation, a lot of the motocross guys I ran with did that in the summer to prevent pinging. I ran VP-red in my CR250R all the time because the jetting on that was so touchy and I needed consistent fuel. $11.00/gallon at one time - ouch!

 

[Snivilous]

Where do you get race gas even? that 50/50 seems a good idea, and I will be wanting race gas this coming spring.

 

[mx21]

Where do you get race gas even? that 50/50 seems a good idea, and I will be wanting race gas this coming spring.

I bought mine by the gallon from a KTM dealer. You can also get it in larger quantities - 5g, 15g, 30g, 54g at a time. Most tracks have it (even more expensive). I've used red and C-12.

http://www.vpracingfuels.com/vp-racing-dealers.html

 

[Vumad]

Don't buy race gas to advance your timing. Buy a MSD ignition with the money you save on race gas. Buy a pipe, buy a new prop, port the motor, etc. Only run race gas if you are running high compression, and only run compression high enough to need more than 91 octane if you have already modded the ski with everything else. Invest in building a quality ski. Don't save $150 on a MSD ignition and spend an extra $7 per gallon because you halfass your ignition system. The math is screwy and doesn't work out in the end. There are much better ways to get power than that.

 

[Austin]

Where do you get race gas even? that 50/50 seems a good idea, and I will be wanting race gas this coming spring.

In loveland you can get it at "us performance" But its $13 a gallon last time I was there getting some for the race car (they buy it by the barrel so it cost more) . BUT I would listen to Vumad, Dont waist your time with it save your money for 750 or 800.

 

[Snivilous]

Don't buy race gas to advance your timing. Buy a MSD ignition with the money you save on race gas. Buy a pipe, buy a new prop, port the motor, etc. Only run race gas if you are running high compression, and only run compression high enough to need more than 91 octane if you have already modded the ski with everything else. Invest in building a quality ski. Don't save $150 on a MSD ignition and spend an extra $7 per gallon because you halfass your ignition system. The math is screwy and doesn't work out in the end. There are much better ways to get power than that.

Pipe, prop, ported, carb, high compression head, nitrous oxide (tentative).

Ok yea, Race Gas sounds kinda dumb. How much higher is the octane on it? The gas station I usually fill up at has 93 octane (one east of Berthoud, Austin) which i was figuring should be just fine. Didn't know race gas was so fancy!

 

[dbattersby20]

race gas would usually be around 110 or higher i believe. No matter what setup i have the money for i plan to always run on 93

 

[Vumad]

Yes, it's 110 octane. You only need add a few ounces to your mix to get the race gas smell.

 

[mx21]

Yes, it's 110 octane. You only need add a few ounces to your mix to get the race gas smell.

I had some older race gas premix that I used for the weed-eater. Every time I mowed the lawn, the smell always reminded me of the track.....

I agree I wouldn't build a ski that needed race gas (unless you are racing at the expert/pro level - which you are not going to do on a 650) - keep it in the pump gas range. Then, you can use it when you are playing around with your nitrous ideas to prevent detonation. VP red (103) and C12 (108) are pretty common - i think C19 was the really high octane stuff (115-117).

Getting back to the original timing question and your ideas of using nitrous, you are better off putting it back close to stock timing....

 

[Snivilous]

Getting back to the original timing question and your ideas of using nitrous, you are better off putting it back close to stock timing....

Yea, no this isn't my thread on it lol. If anything I will be retarding my timing a bit for nitrous since the explosion occurs so much faster. Also be running cooler plugs, 93 octane, was just curious about race gas since I've never used it or even knew where you got it.

 

[kevbo]

The 94-95 cdi has more retard than older boxes. You should be able to advance the stator three degrees. Make sure to mark the flywheel ans check timing with a strobe. Dont exceed 17 degrees at high rpm.