83 kx125 water cooling mods.

[Sandblaster]

At another forum I had this question asked of me:
I have been wanting to ask you about the water pump you messed with way at the beginning of this thread.
I have a 83 KX125 I'm building for vintage mx. It runs a single side radiator. I want to make the cooling system as efficient as it can be. What do I want to do to the pump to get the most flow?
I know that I can smooth any fittings on the inside where the hoses connect . I was a little lost on that you did with the impeller cover

My answer:

The purpose of the impeller mod is to reduce the amount of clearance between the outside of the impeller and the inside of the water pump cover.
Reducing the clearance improves the flow efficiency.
How can you easily reduce the clearance?
Take a look at the diagram below:

kx125 1983 water pump clearance.png (22.13 KiB) Viewed 2624 times

See the highlighted washer?
If you add a washer/shim to the existing washer, your impeller will be closer to the cover improving the flow.
Just be careful, you may have to try a few different washer/shim thicknesses until you get one that does not allow the impeller to rub on the cover.

As you mentioned, look for any obstructions in your system and blend them.
Also, you might want to have your radiator rodded and flushed (If you can find someone to do it)
Also, take a hard look at your radiator.
See all those bent fins?
Get out your pocket knife and straighten them all
Most bikes run cool enough with 50/50 radiator fluid.
DO NOT run more fluid then water.
You might also run 50% water, 45% fluid, and 5% water wetter.
Make sure your shroud and screen are in good condition.
If you have a metal aftermarket radiator guard, replace it with the plastic screen as most of those metal guards are restrictive.
Pull your spark plug and check the color.
If it's grey or white, rejet your bike till is correct.
Make sure your muffler is correctly packed and not obstructed.
The last thing I can think of it add a temp gauge.
Put the probe just before the water enters into the radiator so you know how hot your water is getting at it's hottest point.
Did I miss something?
Probably...

Motorrad?