Tri-Z and In-line Radiator Coolers: Do they work?

[christph]

I've got an overheating problem on my Tri-Z and I'm entertaining solutions. Ever since I ported the cylinder (including an additional boost port) and upped the compression, heat fade has become a problem. It runs like a Banshee for about 5 minutes but then the heat builds up and the power fades. I've got a Sprock cool head and a high flow impeller but it is still a problem. It is not a lean jetting problem; I've dialed that in.

I'm probably going to do a number of things to solve it. One, scrap my DG pipe as I think it is too restrictive and get a Jemco. Two, I'm thinking about trying some inline coolers, the 5 inch ones, not the short Pro-Design ones. Has anyone tried these and did they work? Pro-Design claims a drop of 5 to 10 degrees but that is a pretty big claim, especially for a 2 inch cooler.

Yamaha should have used wider radiator shrouds on the Z. They are tucked-in behind the front fender so they don't funnel air through the radiators. Wider shrouds would have looked cooler, too.

I would also consider larger aftermarket radiators but I've searched the internet and haven't found any.

[XxMurdocxX]

From what i have gathered here at 3ww is there are 2 problems with the tri-z cooling system. 1. Water pump impeller 2. Thermostat. You have fixed one but have you dealt with the thermostat?

[CRAZY70MAN]

Neither of my z's have the thermostat in them. Recommended from the 1-800-Tri-z hotline....aka Raffa....lol Give Bryan a shout or he may chime in on your problem. That fella knows those things inside and out!!

[MTS]

I run the t stat eliminator, only time i have issues is when the rads pack with mud..also straighten the fins out often, my rads are pretty beat up and bent but still cool fine, im also running high compression on 110 leaded fuel.

[Tri-Z 250]

Waterless coolant...sometimes helps keep the temp more consistant and less likely to over heat. You are running Race fuel correct? Condition of the scale build up inside the radiators and thermostat could be an issue and causing the stat to malfunction or not work at all. I've never run into much in the way of over heating. You rad cap is good...seals correct, good flow inside? I am running an eliminator on the race motor with an in-line cooler. That bike isn't going to see much in the way of idle time like a trail machine, with the overflow bottle being pretty handy.

[badass350x]

Chris Im using the Eliminator also!154608

[christph]

So, eliminate the thermostat and it will run cooler? Is the theory behind this that the thermostat is too restrictive, it slows the coolant down, and allows heat to build up?

[zzmegad]

So, eliminate the thermostat and it will run cooler? Is the theory behind this that the thermostat is too restrictive, it slows the coolant down, and allows heat to build up?

well at least then there is no question of the flow through there... plus it looks like his has some cooling fins on it, I guess every little bit helps if you think you are pushing the limits of the Z cooling system. I personally run my t-stat and have never had a problem, I tested it and it was fine so I kept it.

[leevarnado]

Run some engine ice in it.

http://www.engineice.com/

[XxMurdocxX]

For coolant I use evans powersport coolant. Great stuff......... http://www.evanscooling.com/products/coolants/powersports-coolant/

[badass350x]

So, eliminate the thermostat and it will run cooler? Is the theory behind this that the thermostat is too restrictive, it slows the coolant down, and allows heat to build up?

Just something else to fail,,, honesty if it really needed it all the 250R's and other 2 strokes would be using them! So again its just another part to go bad and not having it is one less thing to worry about!!

[pcs]

chris, unless you live in flagstaff i wouldnt worry about need a thermostat, people that live in cooler states dont have problems with thermostats bc cooler ambient temps allow them too, here in hot azz AZ we need all the cooling we can get. i dont feel like getting into a thermodynamic, heat transfer, and coolant flow discussion so check out this link. simplifies everything real eazy. increasing coolant flow with help increase cooling to the engine, to a certain point.
http://www.arrowheadradiator.com/14_rules_for_improving_engine_cooling_system_capab ility_in_high-performance_automobiles.htm

[Bryan Raffa]

Ya take the termo OUT!!! and put it back together... and yes a cooler works anything to draw the heat away and create more surface area for cooling!..it worked great for when it was cold out... but 25+ years later they stick and you over heat...not good out on the trail!

[Bryan Raffa]

Also you got a maire? Or stock front fender? The maire restricts the airflow more into the rad's as the slots are not cut as big.

[Bryan Raffa]

GMX in Australia made a few sets of over sized rad's.. it took me all day to think of it....:cool: no wait it was the UK!!! http://www.gmxradiators.co.uk/

[Kintore]

Just a thought, you didnt mention what kinda fuel you were running? You squished the head some just an idea.

On my 265 R motor, its squished like a fat kid sitting on a candy bar, I have to run a colder range plug along with race fuel and cool head.

[christph]

Thanks for all the input. I'm going to approach the problem in stages. I just took out the thermo valve from the 3-way housing. I put it in hot water to make sure it worked and it did, but I'm keeping it out.

Those oversized radiators from gmx look super cool. I sent them an email and asked if they still sell them and for how much.

I have the OEM front fender, so it is not an overly restrictive Maier front fender that is the problem. I read in an old 3-wheeler magazine that the Z's front fender originally had all the vents cut out, but they had a problem with cold seizing and so they closed up the top two vents. I've considered opening them up.

Regarding my fuel, I'm using Sunoco 110. I know hi-comp motors create more heat so that is part of the problem. Another problem is the DG pipe. I'm thinking it is overly restrictive and builds up heat. I had the same problem on another machine.