Jump to content
Sign in to follow this  

rmz 250 hot problems solved

Recommended Posts

if anyone tries the reduced impeller and works good please post it so we can all do it...!

I plan to pull one out this weekend and give you guys some measurements.

Its a simple mod.

Share this post


Link to post
Share on other sites
I plan to pull one out this weekend and give you guys some measurements.

Its a simple mod.

very well then i wait in anticipation for your reaply,god luck!!

:applause:

Share this post


Link to post
Share on other sites

I meaured a few impellors and found some notes in my book.

I have tried many different impellor mods but wound up cutting down blade height .050 to .100.

I really have no problem with the restrictor. I just feel the less trubelant flow would cool better. There are some others that feel that turbelant coolant helps scrub off cavitation and pinpoint boiling. I havent done any testing comparing the two methods. I just know what works for us.

If I rode slow woods stuff alot I would cut the bladed .050 and if I rode fast motocross or similiar riding I would cut them a little more. Closer to .080.

Share this post


Link to post
Share on other sites

i raced a hare scramble this weekend and it was hell on earth, the rain was so hard there were water falls on the trails. I got stuck on a hill for about ten min and it never over heated. i,ve been realy busy with my work and don't have the time to tear the bike down to give any specs, i looked in the rad to see if any cavitation is there but the coolant is clear.

Share this post


Link to post
Share on other sites

I am not saying this doesn't work because I do not know enough about this particular piece.

However I will say this, in one word, "Balance"

It is a matter of balanced timing of how fast (or slow) a coolant should flow through a cooling system.

Flow too fast and the radiator cannot do its job

Flow too slow and the coolant sits in the cylinder/head/engine too long allowing too much heat soak, essentially from the time the coolant gets from to engine entrance to the engine exit the fluid has soaked up too much heat and you have uneven cooling.

Not to mention that the fluid that is now entering the radiator is far hotter than it was prior, because it's been soaking up more heat.

You might say this is good, but it may not be because now the radiator itself is trying to rid itself of all this extra heat.

People need to look at both sides. Cooling is a system of give and take. If you give a little here, you'll take a little there.

Not saying this won't work, but be careful in how it's done.

Engineers have a lot of factors and crazy algebra formulas used to measure the fluid's rate of volume vs timing vs heat values. Mess with that timing and whatever you add or subtract at one end has to be picked up on the other end.

Share this post


Link to post
Share on other sites
I am not saying this doesn't work because I do not know enough about this particular piece.

However I will say this, in one word, "Balance"

It is a matter of balanced timing of how fast (or slow) a coolant should flow through a cooling system.

I totally agree. This is why in my previous reply I posted

>>"The thing is for different styles/types of riding one may need a different reducer. A desert racer would probally need a different size reducer than a slow woods rider".<<

I think that for the slower riders that never see the rev limiter every straight the stock impellor is fine.

But for faster riders or guys who ride at higher rpm's then in some models the coolant is traveling too fast.

In comparison many stock cars have to run a restrictor in the cooling system even at high speeds.

One would have to test every model in many different riding situations to be able to market such a device. Its easier for the Pro's to see if something is working or not because they are riding at one level all the time,WFO.

We will have more data aquisition equipment installed on a RMZ450 next week(I hope) and on a RMZ250 in 4 -6 weeks.

I plan to make time to do more testing with the impellor.With multiple thermocouples installed in many places in the cooling system you can tell exactly wats going on.

Share this post


Link to post
Share on other sites

Remove the hose from the top of the "Y" pipe. This hose is at the bottom of the right hand radiator and the waterpump. Get a 10mm ID flange nut. (14mm wrench size outside). Drill the threads out, no more than the threads, just the threads so there is less chance of restriction and cavitation. Insert the nut into the steel "Y" with the flange up. Slide the hose back over and tighten the hose clamp like original. Place a zip tie around the hose about 1/2" above the hose clamp. This holds the nut from moving in the hose. That was a Suzuki test restrictor last year. I've put 10-15 of them in and it works great and it cheap...

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×