ping ping

[400exrules]

*check my latest post in this thread*


I rode with some buddies in the snow yesterday, and i have a stage 1 hotcam so it ticks pretty loud. but after riding pretty hard for a few hours, i heard some funny noises and bent over and listened and i heard a pinging noise, i didnt pay much attention to it because i thought it was just the cam ticking, but it didnt sound like the cam. it was a different sound. I run 93 octane gas and it was below freezing outside, what was it?

[2004exrider]

maybe its pre-det. Is the quad running lean?

Jimmy

[400exrules]

yah, it was prob. lean...because it wanted to stall if i stopped and wasnt giving it gas....it would barely idle for a few secs then it would start to choke and stall. Cold weather makes you lean right? Because im usually a tad rich in the summer with my lid off, and i had my lid on yesterday, and its the coldest ive ever ridden in.

what can result from pre-detenation? can it cause any short or long term damage?

[rmz250]

Its gotta be the canooter valve.

[humblesquirel21]

lean cause of the cold my guess i adjusted min to run perfectly in about 55-70 degree weather and when i ride in weather below the 20s it has simialr symptoms

[zrpilot]

If your jetting for 155 at 68 deg and 1000ft ASL. Then at 20deg you would have increase your main jet about 4-5 jet sizes to about 162/165.

Detenation is not good, it creates hot spots in the combustion chamber that leads to things such as burned valves, accelerated beaing wear, ETC.

Please do your quad a favor and re-jet before you ride when its that cold.

Zrpilot

[NacsMXer]

Originally posted by 400exrules
yah, it was prob. lean...because it wanted to stall if i stopped and wasnt giving it gas....it would barely idle for a few secs then it would start to choke and stall. Cold weather makes you lean right? Because im usually a tad rich in the summer with my lid off, and i had my lid on yesterday, and its the coldest ive ever ridden in.

what can result from pre-detenation? can it cause any short or long term damage?

Yeah, colder weather makes your air/fuel mixture leaner than normal. Also pre-detonation is a very bad thing that can cause serious engine damage. When that happens, the air/fuel is combusted before the piston reaches TDC while it is still on the upstroke. So all that power that results from the combustion is trying to push the piston back down while it's still trying to go up. This creates immense internal pressures that could blow your piston and rod to pieces if the pre-detonation is significant enough. While this is in the most extreme cases, it is still very possible.

[400exrules]

ohhhh sh%t......do you think it could have caused a decrease in power? i havent ridden it since i put it up yesterday since is cold as ballz

oh, and i was cleanin my carb the other day and i checked my main jet, and its a 146 dynojet...i have a slip-on, filter, and a cam. does that sound about right? the previous owner jetted it. it runs great in warm weather, that just seems kinda low for a main

[NacsMXer]

Yeah you would definitely have seen a decrease in power if you were jetted wrong. Don't worry though, you may have had some minor predetonation, but if it was serious, you would have known by now. I would bump up the main jet a size or two for this frigid air. It would be good to also turn out the fuel screw on the carb about a 1/2 turn to richen it up some. You may or may not need to change the pilot jet too, but see how it runs with other changes, then adjust it accordingly.

[bwamos]

Originally posted by 400exrules
ohhhh sh%t......do you think it could have caused a decrease in power? i havent ridden it since i put it up yesterday since is cold as ballz

oh, and i was cleanin my carb the other day and i checked my main jet, and its a 146 dynojet...i have a slip-on, filter, and a cam. does that sound about right? the previous owner jetted it. it runs great in warm weather, that just seems kinda low for a main

According to the dynojet instructions for the 400ex. No Airbox Lid, & Aftermarket exhaust below 3000ft = Needle in 3rd slot and a DJ 170 Main.

DJ 146 Main with stock filter and lid on (unpunched).



http://www.dynojet.com/pdf/Q107.pdf

These reccomendations do not include a cam or aftermarket filter. You definatly need to adjust for the cam as well especially when the lid is off.

[400exrules]

but it runs great in warm weather. i even did a plug check before winter when it was warm, and it was alittle rich. It might not be a 146, i could have read it wrong.
1)when you get jets, can you get like, a kit with a whole bunch of different sizes or do you have to buy them individually?

2)Could the pre-det. from the other cause me to have a permanent power loss?

3)has anyone tried those meters (not sure what they are called) but you hook it up to your quad somehow, and it has a bar of red and green lights, and it tells you if your lean, rich, or if your jetting is good. Seems easier then doing plug checks, especially since the 400ex plug is crammed in their

Im not gonna change my jetting right now because i probably wont be doing any more riding till it warms up a bit. Winter is just about over here anyways.

and thanks, so far, for replies :)

[rooster300ex]

I would say you have a very touchie(ey) jetting.

[Old Head]

If you read it right and its a 146 that would be smaller than stock for where you live. Did you do the plug check with a fresh plug? You need to wind the bike out in like 4th pull in the clutch and cut the motor without backing off the throttle. I run a 170 main and usually don't have to reinstall my lid until its below 20 degrees. Air is denser the colder it gets which creates the lean condition.;)

[Sleeper]

Originally posted by Old Head
If you read it right and its a 146 that would be smaller than stock for where you live. Did you do the plug check with a fresh plug? You need to wind the bike out in like 4th pull in the clutch and cut the motor without backing off the throttle. I run a 170 main and usually don't have to reinstall my lid until its below 20 degrees. Air is denser the colder it gets which creates the lean condition.;)

Are you running a .170 Keihin jet or a dynojet?

Sleeper

[jordan_m6]

i believe we are pretty close to the same alt. and i am running a 175 with no lid, a k&n, a cam and a 11:1 piston. when stock it came with a 148.

[jordan_m6]

Originally posted by Sleeper
Are you running a .170 Keihin jet or a dynojet?

Sleeper

He said it was a DJ

[jordan_m6]

[QUOTE]Originally posted by 400exrules
[B]but it runs great in warm weather.

just cause it is running doesnt mean that the amount of fuel delivery is correct.

how is the mixture screw set are you 2.75 - 3 turns out or are you past that.

[Sleeper]

I think Jordan's on to something with your mixture screw. It controls richness at idle and a hare off idle then your pilot jet takes over from around 1/4 to 1/2 throttle and DJ says you don't have to mess with the pilot jet with thier system..

of course if your main jet is way to lean you could be getting it so hot that even with the proper settings on the mixture screw you could ping bad until it cools.

Sleeper

[jordan_m6]

well this was my problem i was running rich but with the mixture screw was 4.5 turn out and ran fine but it was feeding to much gas.
yea never had a problem with it, just had to run 93 octane or it would spark knock
i figured this out after i burnt up a few spark plugs and cleaned the carb.

[Sleeper]

I've had mine ping stock everything with 93 octane I can't imagine with your set up. My next step is to bump the compression. Gonna wait a bit though.

Just reworked my carb today after a bunch of mods. went another half turn out on the screw, moved the clip on the needle to pos #4, put a 40 slow jet in and a 158 main jet. Hoping that will do it but I'll be packing 162, 165, 168 with me. Easy to change in the field. That slow jet is a PITA.

sleeper

[jordan_m6]

Originally posted by jordan_m6
well this was my problem i was running rich but with the mixture screw was 4.5 turn out and ran fine but it was feeding to much gas.
yea never had a problem with it, just had to run 93 octane or it would spark knock
i figured this out after i burnt up a few spark plugs and cleaned the carb.

this was before the 11:1 and cam i just put those it 2 weeks ago, but due to the new pit crew member the gf spit out wendsday i havent got to ride

[Sleeper]

Originally posted by jordan_m6
this was before the 11:1 and cam i just put those it 2 weeks ago, but due to the new pit crew member the gf spit out wendsday i havent got to ride

Congrats!!

Sleeper

[400exrules]

what does the fuel mixture screw control, like....all areas of throttle, or just off idle? im gonna have to agree and say thats all i can guess is my mixture screw is too far out, and thats why the main is small.

do i need new spark plugs to do spark plug checks? and how would i check the main, run wide open in 4th and pull the clutch and cut it off?

thanks

[400exrules]

bump^^^