I have been riding my DS in the trails quite abit lately. My fan has been coming on within abot 10 minutes of riding. The temps have been 90-95 degrees here the last few days. I actually had my light come on saying that I was overheating. Is there another coolant that I can add that helps keep things cooler. I am going to get a temp gauge installed just to see the temps. Is there anything else I can do to help keep it cooler during summer trail rides? Thanks.

 

What size main jet are you running in your carb? You may be running a little lean, which can make your engine run hot. You can compare jetting settings on a link on my webpage to other ds owners.

 

The thermostat opens at 185, the fan comes on at 221, and the red light comes on at 239. I've only had a red light come on from a dead fan, and I ride tight slow trails in 95-100 degrees frequently. My guess is you have something not right, either too lean like Buttfungus said, or a cooling problem, perhaps a bad thermostat that's not fully opening, or defective water pump impeller, etc. Running lean makes more of a difference than a lot of people realize, don't overlook this possibility. Also make sure there is no mud in your radiator fins.

There are coolant addatives that claim to lower temperatures, but I've read some bad as well as good on all of them and can't convince myself to try any. Since water is a better heat dissipater than antifreeze, you can dilute the mixture from the stock 60/40 glycol/water to help a little. Just don't go less than 25% glycol for corrsosion protection, from what I've read on various studies, and don't forget to bring it back up for proper freeze protection this winter. There are more comments on this stuff at a thread discussing fans, do a search and read some of it if you want.

 

Just a thought here. Do you trail ride with mostly part/half/full throttle? Doesn't the main jet control the A?F ratio from 3/4 throttle to full throttle? He might be better off adjusting the needle clip more. Is this a possibility or am I way off base here. I am new to carburuetion, I'm used to the "old school" fuel injected 302 [img]i/expressions/face-icon-small-smile.gif[/img]

 

You're not off Rockey, if your lean at 1/4 to 3/4 throttle, the needle can be it, but even then the gas goes through the main jet also, so the main can also play on the mid throttle as well. The best direction to go in jetting is dial in the main, then the needle.

 

I run 1/2 to full throttle. The bike is clean so no mud in the fins. Um...I did jut get it piped, but I have not jetted it yet. I runs like a stripped a$$ ape without jetting it, so I just let it alone. You think that could be the problem?

 

<< You're not off Rockey, if your lean at 1/4 to 3/4 throttle, the needle can be it, but even then the gas goes through the main jet also, so the main can also play on the mid throttle as well. The best direction to go in jetting is dial in the main, then the needle. >>



Thanks hightower. Your not too far from me. Ever been to Badlands? I was thinking about making a trip up there if it was worth it.

 

Yeah, my Baja does the same thing, fan comes on within 10mins, but I can tell it is a little lean on the MJ because when I start it, I've never had to use the choke. I also moddified the end cap, which leaned it out a little.

 

Any change in air flow at all, be it a modded end cap, different pipe, K&amp;N air filter - anything - requires jetting. Adam's open end cap, and 02baja's white bros. pipe definitely require jetting, and are both lean - way lean. Even just taking the lid off the air box would require jetting. A motor will actually produce a bit more power if leaned, but excess heat comes with this so it is not a good idea. This is why you thought everything was alright, because it ran okay, but the tradeoff is less life from excess heat.

Look at Buttfungus' site, the listing for jetting mods, and compare what you have to other people's settings. Pay particular attention to altitude, its on the list too, because it matters. When in doubt, if you think you are lean, jet up. Being a little rich is better than being lean, becuase it won't hurt the bike, lean will.

Be advised - Dynojet jets are not the same as Mikuni jets - the number doesn't mean the same thing. Buttfungus has a conversion chart on his site too. Refer to it for accurate translation. More than likely, both of you need to go up somewhere around 180 Mikuni on the main if you're running a K&amp;N too.

Rockey - I'm at Badlands every month, live one hour from it.