Hi all,

Anyone have experience with oversize radiators for the 4RT? (I have a 2015) thinking of fitting one to help with the heat here in the land down under. 38 degrees C here yesterday........

-Do they usually fit without modification?

- Any good suggestions for a supplier?

Thanks,

Mark G

No experience with the brand or if they ship to land down under, however there is one you can get from H & D Racing, and I have heard good things about them.  

 

http://www.handdracing.co.uk/userimages/procart2.htm about half way down the page titled "4RT Alloy Racing Oversized radiator"

 

Good luck!

Edited November 22, 201510 yr by jonnyc21

I too live in a VERY hot place (Arizona). I think that the 4RT here would benefit more from an oil cooler more than a larger rad.

 

 

In this years Scott I think mine was starting to run too, Every now and then it would fail to pick up off the bottom end when opening the throttle hard, similar to having crap in the carb. It was getting slightly more frequent until I punctured, stopping to fix the rear allowed it too cool down enough. The radiatior was very clogged with Yorkshire which must have been the cause.

Has anyone else experianced overheating? It never threw any water out or didn't seem to run lean, it just stuttered.

Got me thinking about an oversize radiator.

Has your bike got a big bore kit on it john?

No its just standaed

If I can get my act together I'm hopeing to have another crack at the Scott next year. I've got a 280 mitani kit on my 4rt and do notice that it runs quite hot. Do you think an oversized rad is something to consider? By the way john, I'd be very happy just to finish in time, I don't think you'll have to worry about me troubling you for standard time!!!

I'd consider it more if I had the 280 kit. For next year I'll be putting some fine mesh over the rad cover to stop the crud getting to the rad. Cheaper option!!! The fan runs pretty much constantly so the large radiator must help.

Does the 300rr or the 260's have a larger radiator?

don't think so my 15 260 has the same rad as my 05, don't know bout the 300rr, no one got one to look at yet lol

I don't know to be honest. But you just answered my next question, to put some mesh over the rad shroud to stop the crap getting in. I'm sure I saw that on the gasgas team bikes.

Is there something better than water to put in as coolant to try and keep things cooler, neat antifreeze perhaps?

Whilst I have your attention, what gearing do you run mr sunt?

I don't know to be honest. But you just answered my next question, to put some mesh over the rad shroud to stop the crap getting in. I'm sure I saw that on the gasgas team bikes.

Is there something better than water to put in as coolant to try and keep things cooler, neat antifreeze perhaps?

Whilst I have your attention, what gearing do you run mr sunt?

I have been running Engine Ice in my 4RT and it seems to be working great for me.  

Definitely use coolant, and have heart good stories about ''better'' working coolants which are offcoarse more expansive.

 

A bigger radiator doesnt solve your problem, if the bigger one gets dirty it also does not cool enough anymore.

Edited November 23, 201510 yr by crazybond700

Oh dear me, £7k on a bike and its radiator is barely up to the job

Coolant - a coolant has to have 2 key properties, firstly it has to have high specific heat capacity and secondly it has to "wet" the internal surfaces of the water passages.

Water has a specific heat capacity of 4,200 J/kg/degreeK

Undiluted antifreeze only has a specific heat capacity of about 2,760 J/kg/degK so it is nowhere near as good as water.

Probably the best mix is about 25% OAT antifreeze which has the wetting additives and a heat capacity of about 3,990 J/kg/DegK.

Dadoff you ever been to australia (38 dgrees he said)? To expect every trials bike to be capable of every conditon worldwide is silly in the extreme. Especially for 7k (which bike ais 7k?)

Oh dear indeed.