Has anyone had a BAD experience with a +6 timing key?

[400exstud]

I know that it doesn't make that much more power but it would be perfect for me IF it ratains the stock releability. So...... has anyone ever had a bad experience with one?

i have never heard of any 1 having a bad experience with one but i heard it not good to do on a really moded quad but it works grate for a stock engin

[400exstud]

Yeah. I figured that its only $20 so what the heck.

ya i would go for it

[400exrider707]

They add heat is all, from advancing the timing. Not recommended on modded engines, but mostly stock is OK, but I definitely wouldn't run one with a rev box that has advanced timing like the GT Thunder or TC box's.

[chad502ex]

everyone with a 400ex should have one of these. best $15 plus gasket i spent on my 502ex.

there should be a flood of calls into curtis sparks right now for this,.... :D

[400exstud]

Sounds good! I'll be ordering one shortly.

[chiaml]

Where do you get one?

[400exstud]

www.sparksracing.com

[guinness77]

I got one installed on my 04 400ex. My motor Mods are: White Brothers E-Series pipe, Power-up jet kit for the carb, and a K&N air filter. I Noticed a good difference in my mid-to-high end performance after that Sparks key was installed. It was nice to have 3rd and 4th with more power. With 87 octane gas I noticed knocking and pinging (detonation). So I knew I needed a fuel/air mixture that burned a little more slowly. So I tried 92 octane. that was good. But when I went to 99 the quad was running sweeeeeet. (I knew I didn't need to go beyond that octane with a stock compression piston). But there was a LOT more heat. (Air scoops helped loads... but there was still more heat.)

Now the enginge is apart to deal with a counter shaft problem and 5th gear problem. The mechanic was puzzled by the deposits on the piston, valves, etc. It was white. Not dark. For $20 it's a great deal. But there are trade-offs. (If anyone can tell about the white deposits please speak up.)

I've decided to go up to a 402 with a W/B performance cam. And I'm pulling the timing key.

[krt400ex]

Originally posted by 400exrider707
They add heat is all, from advancing the timing. Not recommended on modded engines, but mostly stock is OK, but I definitely wouldn't run one with a rev box that has advanced timing like the GT Thunder or TC box's.


they do add heat, but not enough to notice. i have one and i can't tell the diff in temp at all. there is more low to mid power and a noticable diff in throttle responce( it is better)

[GPracer2500]

Originally posted by guinness77
....So I knew I needed a fuel/air mixture that burned a little more slowly....
That's not quite right. It's of little consequence to this discussion, but I'll go ahead anyway...

A fuel with a slower flame speed is actually more likely to detonate. This is because of the same reason that lots of ignition advance creates conditions that favor detonation. The longer it takes for the end gases in the combustion chamber to be consumed, the more time there is for that fuel to degrade into the unstable chemicals that are responsible for detonation. Starting the combustion process sooner (lots of ign adv) or having a fuel with a slow burn rate adds to the amount of time that the end gases in the combustion have to wait before deflagration can consume them.

Octane rating is best thought of as ONLY being a measure of a fuels resistance to deto. Some high octane fuels might have fast flame speeds while others might have slower flame speeds. Flame speed factors into the octane rating of a fuel but it is not the primary determinant of the rating. Trying to extrapolate burn speeds, energy content, or any other fuel quality (except deto resitance) from octane rating in usually a mistake.



Originally posted by guinness77
...But when I went to 99....The mechanic was puzzled by the deposits on the piston, valves, etc. It was white. Not dark...
What was the 99 octane fuel? Was it leaded? Sounds like the white (grayish?) deposits are lead deposites. Where there a lot or just a wisp of these deposites?

[guinness77]

Originally posted by GPracer2500
That's not quite right. It's of little consequence to this discussion, but I'll go ahead anyway...

A fuel with a slower flame speed is actually more likely to detonate. This is because of the same reason that lots of ignition advance creates conditions that favor detonation. The longer it takes for the end gases in the combustion chamber to be consumed, the more time there is for that fuel to degrade into the unstable chemicals that are responsible for detonation. Starting the combustion process sooner (lots of ign adv) or having a fuel with a slow burn rate adds to the amount of time that the end gases in the combustion have to wait before deflagration can consume them.

Octane rating is best thought of as ONLY being a measure of a fuels resistance to deto. Some high octane fuels might have fast flame speeds while others might have slower flame speeds. Flame speed factors into the octane rating of a fuel but it is not the primary determinant of the rating. Trying to extrapolate burn speeds, energy content, or any other fuel quality (except deto resitance) from octane rating in usually a mistake.



What was the 99 octane fuel? Was it leaded? Sounds like the white (grayish?) deposits are lead deposites. Where there a lot or just a wisp of these deposites?

It is 110 octane filtered leaded racing gas from Northwestern supply out of Eugene, Oregon. There were quite a bit of those deposits. They are quite white. I always read that the higher the octane the slower the burn. So higher compression pistons and earlier sparks could take advantage of a LITTLE higher octane. I mixed it with 92 in very careful quantities to come up with 99.2. Interesting input.

[GPracer2500]

Originally posted by guinness77
It is 110 octane filtered leaded racing gas from Northwestern supply out of Eugene, Oregon. There were quite a bit of those deposits. They are quite white. I always read that the higher the octane the slower the burn. So higher compression pistons and earlier sparks could take advantage of a LITTLE higher octane. I mixed it with 92 in very careful quantities to come up with 99.2. Interesting input.

My guess is that the white deposites where from the lead. Most (all?) leaded fuels containe an additive called ethylene dibromide that acts to scavenge lead oxide deposites from the inside of the combustion chamber. I'm not for sure, but it could be that some leaded fuels have less of these scavenging additives than others [shrug].

Engines don't really take "advantage" of higher octane. At least that's not the way I'd recommend thinking about it. That way of thinking suggests (to me) that an engine might run fine with one octane (no deto) but run better with a higher octane. That's never the case. An engine has a minimum octane requirement. Below that requirement the engine may not combust air/fuel mixture normally. Going above that requirement adds nothing. This point highlights that octane rating is only one property that distinguishes one fuel from another. There may be some other quality of a high octane fuel that's independent of octane rating that allows the engine higher performance. But once an engine is fed a fuel with an adequate octane rating more octane rating offers no advantage. Octane is just one of many properties that distinguish one fuel from another.

Here's a thread in which I go into more detail about what detonation is and how octane is related: http://www.exriders.com/vbb/showthread.php?s=&postid=2406397#post2406397

[guinness77]

Originally posted by GPracer2500
Engines don't really take "advantage" of higher octane. At least that's not the way I'd recommend thinking about it. That way of thinking suggests (to me) that an engine might run fine with one octane (no deto) but run better with a higher octane. That's never the case. An engine has a minimum octane requirement. Below that requirement the engine may not combust air/fuel mixture normally. Going above that requirement adds nothing. This point highlights that octane rating is only one property that distinguishes one fuel from another. There may be some other quality of a high octane fuel that's independent of octane rating that allows the engine higher performance. But once an engine is fed a fuel with an adequate octane rating more octane rating offers no advantage. Octane is just one of many properties that distinguish one fuel from another.

I read the thread. Thanks.