CR 125 H2O temp?

Kevin Callahan · Posted: Thu Jul 26, 2001 12:32 pm Post subject: CR 125 H2O temp?

Hey everyone,

Yet another in my endless series of idiotic novice shifter kart questions. Do cr125 motors run a thermostat? And what is the standard opening temp.? My motor is blueprinted (so I'm told) but otherwise stock. I ran last weekend with a radiator that seemed small compared to others at Perris in So Cal. My H2O temp. was about 155 degrees. I understand that 135 or 140 is where you want to be and I'm looking at ways to cool off a little bit--my motor, that is, I'm already cool! hehehe

Thanks

Tim Blaney · Joined: 18 Jul 2001 Posts: 1127

Kevin,

No, the CRs do not have thermostats and you're right, 155 is too high. To improve your cooling, you can try, getting the rad into cleaner airflow (stand it up) or make some ducting to force more air through.

If these do not work, you might have to think about getting a bigger rad.

Ronnie Swyers · Joined: 23 Jul 2001 Posts: 95

Kevin,
No, there is no thermostat. The optimum temp for your motor is going to be 125 - 138 degrees. Power starts falling off after that. How much will it fall off...I don't know. If you run much colder the chances of a cold stick are greater with a motor that has tight tolerances. Some motors run warmer because of timing advance, compression ratio and fuel mixture. More power, more heat and the need for more water. Hope this answers your question.

Racingron www.RSwyers.com

Kevin Callahan · Posted: Thu Jul 26, 2001 1:33 pm Post subject: CR 125 H2O temp?

Thanks for the suggestions. The rad is leaning pretty far back, so tilting it up and shrouding it was going to be my first move.

Ronnie, timing advance and compression ratio are unknown by me at this point, but fuel/oil was 28/1 w/Union 76 110 racing fuel.

Gary Kozuma1 · Joined: 26 Jul 2001 Posts: 386

Hey Kevin,

Welcome to having more fun than should be legal. On the Rad thing, another thing to think about is what the engine temp is relative to the air temp. So if it's 80 degress ambient and the motor is running at 130 the difference is 50 degrees. So long as it stays 80 your good. But if it's 100 ambient, then you'll be at roughly 150. That's bad. So what I'm shooting for (not there yet!) is a 30 degree difference. So when it's 105 at Willow (what am I thinking about racing when it's that hot?) the motor will be at 135 or so.

Also, when you get to where you want to be, be sure to tape your radiator when it gets cold. That mininum temp is not a power thing, it's a cold sieze thing.

Gary K.

Ed Weathers · Joined: 19 Jul 2001 Posts: 36 Location: Hood River, Oregon

quote:
Originally posted by Ronnie Swyers:
Kevin,
No, there is no thermostat. The optimum temp for your motor is going to be 125 - 138 degrees. Power starts falling off after that. How much will it fall off...I don't know. If you run much colder the chances of a cold stick are greater with a motor that has tight tolerances. Some motors run warmer because of timing advance, compression ratio and fuel mixture. More power, more heat and the need for more water. Hope this answers your question.

Racingron www.RSwyers.com

Tighter tolerances and timing advance? Hey Sweers you run one of them hopped up motors?

Jeff Morningstar · Posted: Fri Jul 27, 2001 3:15 am Post subject: CR 125 H2O temp?

Temp is a big problem. 150 your power will drop off. so try to stay around 135.

Kevin Callahan · Posted: Fri Jul 27, 2001 7:54 am Post subject: CR 125 H2O temp?

Thanks, Miamisburg, OH. There sure must be a lot of shifter karters in that town...do you hold elections to decide how to respond to posts??? http://www.ekartingnews.com/ubb/biggrin.gif