'07 Apex running hot / need rear exchanger advice

[gitrdun]

Here is some more info. The old part number for a 121 heat exchanger in case they are still in stock somewhere, is 8ET-RHECR-KT-00. Check out ""Help" Rear Heat exchanger" by Bigwin from Jan.25,2007 where ROCKERDAN gives detailed instructions on a 121 inch. Also, "Rear heat exchanger install...pop rivet tool" by kinger from Oct. 10, 2007.

 

[ROCKERDAN]

hey guys,....this is very typical for hardpack running higher speeds on these sleds stock.

My coolant tester also was "off the charts" when i checked stock coolant...so I reduced the mixture to approx 50/50 and now tester shows minus 34F... which is good.

also,added watter wetter.....and also the rear exchanger ,no way will this thing show a temp light ever again..even on long roads!.

here is a link to some of my install pics and step by step.
http://www.ty4stroke.com/viewtopic.php? ... +exchanger

Dan

 

[Blue Dave]

Thanks ROCKERDAN!

As I mentioned, I also plan on doing the "triple fix" of adding the rear heat exchanger, diluting the mixture to 50/50 and adding Water Wetter.

The pics were very helpful! However your rear heat exchanger looks much smaller than I expected. Is it the Yamaha or aftermarket?

Did you use 1oz / Qt of the Water Wetter or just pour in the entire 12oz just to be safe?

Thanks again for all the help!

 

[ReX]

I can't say much about the Attak, but the Apex and other short track sleds definitely run hot with the close to 100% antifreeze they come with and once diluted to 50/50, the stock cooling systems work very well.

To give you an idea of the difference with the coolant mix:

I've seen the light turn on trail running on icy or very hard packed trails with the stock coolant mix.

With a 50/50 mix, we got stuck coming into Cochrane last season when the snow completely disappeared. We couldn't turn back because we didn't have enough fuel so all we could do was keep going. After something like 50 miles of torture (for us and the sleds), riding without a hint of snow, the coolant light would only flicker on and off if we stopped and idled for a minute or rode too slowly. As long as we kept moving at about 30 mph, the light wouldn't turn on at all. Obviously the radiator fans on both sleds ran 100% of the time too. Luckily the snow then improved and we were able to make it the rest of the way.

On that same trip we rode a huge number of miles on nothing but rock hard ice covered trails. On the ice we rode the sleds hard, often at wide open throttle and lots of high speed and hard braking. The ice chips from the studs combined with the radiator fan was again able to keep the coolant light off all the time.

Since the Apex can keep from overheating without snow if cruising at low/medium speeds and can handle rock hard ice trails without overheating, for me I don't really see a need for the rear cooler (unless your ice racing or something).

The much bigger issue is hyfax heat and wear when running on ice or no snow. We went through (and I mean right through) 4 sets of hyfax on the 06 Apex ER on that same trip. My 07 RTX survived with only one pair (paper thin at the end) but I was running 04 RX-1 idler wheels, had an extra pair installed too and with the Skidoo anti-ratchet drivers had my track very loose. Even though my hyfax survived, this season I'm running 4 Skidoo idler wheels at the front to further improve hyfax wear (135mm diameter instead of 130mm).

 

[Blue Dave]

Thanks for the input Rex.

I just want to be 100% worry free so I am adding the rear heat exchanger as well as diluting to 50/50 and adding Water Wetter. Just not sure if I should add as recomended 1 oz / Qt. or just put all 12 oz in.

Bruce at Pioneer sells the Yamaha heat exchanger for $81.95 which is about half what my dealer wanted. Not sure how he can sell it so cheap but I'm not complaining.

 

[CaptCaper]

At 50/50 what happens to the antifreeze when it's 40 below..? We can get that here for two weeks straight. I would worry it would expand too much and pop something.
I've left the mix strong for now with my rear cooler installed..If it overheats again which it hasn't since putting it on I'll dillute. My friends twin Pantera Cat's (80hp) have overheated while we were riding with them in temps from 5 to -5 F...we didn't.

 

[Blue Dave]

Good point Capt. It can also get that cold in Northern MN from time to time.

Even if I dilute to 60/40 (which is what Yamaha says it is) it will still be whole lot better than what I have since it is off the scale of my tester and looks like 100%

 

[ReX]

At 50/50 what happens to the antifreeze when it's 40 below..? We can get that here for two weeks straight. I would worry it would expand too much and pop something.
I've left the mix strong for now with my rear cooler installed..If it overheats again which it hasn't since putting it on I'll dillute. My friends twin Pantera Cat's (80hp) have overheated while we were riding with them in temps from 5 to -5 F...we didn't.

If it gets below -40 for weeks you definitely need a stronger solution.

In reality, a mix of 50/50 taken down to -45 or -50 most likely won't expand much, but it likely won't flow and likely will overheat the engine if you run it.