hmmm never considered the fuel.... i have the big gun cdi (i dont know if the power curve advances/retards timing....but i have also just recently (might line up with my heat problems actually...) to 87/89 octane instead of the 93 that i used to run.


well now that i think about it maybe the fuel my freinds dad was buying on this trip was premium (91-93) I know they have to run 93 for the computer chip in the suburban so maybe he filled the cans with that too....

might be a good t est.... finish off whatever is in there now and then go run a tank of 93 and see what it does...

 

All the DS's I ride with run hotter than my Raptors. I should say their fans are on a lot more and longer. They may not be running any hotter. I don't know what the fan relays are set to come on at on either quad. I always assumed the Ds's ran hotter because the radiators are behind to many air blocking objects and the Raptors are out front catching the air as you ride. Just my 2 cents.

 

Doctorturbo is correct. Different types of fuel causes different plug colors. Again, another reason why I don't look at the plug color.

Sam, you cannot check the mixture at idle, then in the middle and then at the top. You have to check it across the whole RPM range. It can changes dramatically across the RPM range. Within 1000 RPM it can go form a good mixture to a bad one and back again. You need to know where that mixture goes wrong and adjust or chage the right component to fit it.

The best is to put the bike on a dyno and run it form idle to max RPM with full throttle. If you don't have a dyno then you need to get an air to fuel ratio meter and ride the bike on the road and see what it does. 4th gear is best.

The DS also have a CV carb, and the carb automatically adjusts to the motor. You can have the throttle wide open, but the slider might not be. The thumb throttle position is not always correct on a CV carb as the slider constantly adjusts to the engine requirements. The slider works on vacuum and depending on how much the motor is sucking air, it will open more or less. At lower RPM, even with WOT, the slider might only be half open, hence you having to test the mixture across the RPM range.

This is why Mr HP recommends cutting the slider spring. I believe he recommends you cut 4 turns off. Less spring tension will open the slider faster and larger at lower RPM and give you a bit more power lower down. It will not affect max HP as the slider is usually wide open at 5500 RPM plus, no matter how soft the spring is.

If the spring is too soft you might pick up problems, so don't go cutting the thing to much.

 

There is some debate about cutting coils from the springs. Cutting to many coils could actualy make that spring harder to compress.

 

Mine doesn't hardly ever run......I should check it to make sure it works I guess.[img]i/expressions/face-icon-small-happy.gif[/img] Do you notice everyone staring at you? Some one behind you..(easy yahama joke but I'll leave it alone)...Who's out to get you?

J/K or am I really


marrtoo

 

My '03 BAJA runs seems to run hot, too. The fan works alot. It would be nice to have some gauges to know what 's going on. I'm not sure what the optimal temp is. Anyone? My friends are sick of the fan. Everytime we stop, my fan is still running for about 5 minutes.
As for riding with shorts? Your joking, right?

 

when we are just put-putting around i usually wear shorts/tshirt (helmets/gloves boots are ALWAYS on though) but when we start riding anything over 2nd gear stuff im usually wearing jeans/riding pants.... but its that slow riding that is the worst (not much air flow to carry all that heat away)

ya everyone i ride with seems to hate the fan as well...you cant hardly even talk over it, its so loud.

 

Well I run royal purple's coolant additive. (Purple Ice) My DS fan does comes on when I run it hard and just sit there now, though most the time it was not on for very long. But in the winter time my fan allmost never came on.
Maybe try one of the many coolant additves out there to try and help reduce coolant TEMP.
I do live in the desert (Mojave CA.) so heat is a big thing out here, I do run a MX track at Edwards AFB during the week as well so I do beat on my DS. (Poor thing, 210pound guy with 500pounds of quad) Nothing like 710pounds of fury(well in my mind it's fury) flying through the air. HEHEHEHEH!

 

Roost - I have a DS, and I have a temp gauge on the coolant line coming from the thermostat housing. I consider myslef a very good tuner of the TM45 carb, unfortunately I have not played much with the stock carb. SO take my comments for what they're worth but most will apply to you and your bike.

The coolant temp of the DS will ALWAYS be higher than a bike that has a sleeved cylinder. The aluminum/nicasil cylinder of the DS dissipates combustion heat so well that the coolant is carrying away more heat than its sleeved counterparts like the Raptor. The result is a higher coolant temp yes, but lower head temps inside.

Improper jetting can make a bike run hotter yes, but just for FYI, since I have a temp gauge and I'm very confident of my jetting everywhere I ride, I can honestly say that 200 degree coolant temp is very common for the DS, and when I ride tight winding slow trails or make a few hard full throttle climbs up Sand Mt. Utah winding out 7600rpm in 3rd gear all the way up for nearly half a minute, my temp gauge will get up to 205 in a heartbeat.

The fan switch comes on at 203, but doesn't kick back off until coolant temp gets back down to 194 - this is book spec confirmed by my temp gauge also. The red light comes at 239 degrees - which is really hot obviously. If the red light comes on, then there's a problem - 239 is really hot!

The radiator is mounted low yes - but the oil tank is mounted high and gets a little cooling airflow through the nostrils. I put an inline cooler on the oil line coming from oil tank to the motor, to help keep the bottom end and the clutch cooler - but I don't know if this helped because I don't have a temp gauge in the oil line.

How do I jet? I jet for the most power and fastest acceleration. Sand Mt. is the perfect place to jet - you make a Mountain run looking at the tach, then change a jet and run again. The jet that gets you to the top the fastest is the jet that stays - this is the same principal as dyno tuning, but free. Screw plug checks - they are decieiving to too manay people, and everybody has too many opinions on how to read it. I even have my own, and I believe it to be true, but I'll not bother writing it. But one thing I will say is that if there is any soot on the plug then you are too rich somewhere - but where is another thing (idle,needle,main).

Just FYI on jet changes have to make - I use a TM45 - at home 700' elevation - 157.5, Sand Mt. Utah 5K - 150, Walden Co. 9K - 145
My rule of thumb for elevation changes on my bike with my carb is drop one size (2.5) for every 1500 feet - this does not consider temp and humidty changes so trial and error for that final tune may be needed. I've proven this rule of thumb using the method of jetting described above on the Mountain. But I don't what effects the altitude has on the vacuum slide of the stock carb so I can't say this rule of thumb would hold true for you.

I feel the slight power loss when my temp goes from 195 to 205 on the Mountain - I wish I could keep it down at 195, but I'm not sure if its possible. And for that matter, if I'm 205 then the guy next to me has a head temp at least equal if not higher than mine, so its not that big of deal. but I still want the temp down below 200, but I'm not sure its possible. My supercoolers are huge - the longest made, they had no significant impact, maybe a couple degrees. radiator scoops won't help I run the hottest on slow trails in 2nd gear - there's no air to scoop. my entire exhaust is ceramic coated - no real impact on coolant temp, although the headpipe is significantly cooler so my head is probably better off. Engine Ice? Well I'll try it, but since everything else I've tried that others have sworn by proved not much help, I don't hold a lot of faith in this Ice either...but we'll see...

 

very good info to know.
How did you rig up a temp guage to the thermostat housing? i dont beleive i will every be truly "not worried" about the heat unless i have a way to actually SEE what the heat is.....

my red light has never come on...which is probably a good thing lol. But if the fan kicks on at 203 i must be peaking around 205-210 (HOPEFULLY not more.)