KX Guru Racing

Ported impeller cover, and elbow

You know... we have looked at a lot of different things for cooling...
But what about the head gaskets?
Sure seems like some small holes for the water to flow through..



I know that the one side has to be smaller then the other for forcing the water flow to the opposite side of the head but this is getting a little smaller then I think is required...
What do you think?
I think it's time for some calculations and some modifications..

All those holes will flow 3x more water then most MX cooling system could flow. You could make the holes larger then go out and test it on the street with your SM bike.

Qsixteen wrote:All those holes will flow 3x more water then most MX cooling system could flow. You could make the holes larger then go out and test it on the street with your SM bike.

That is already in the works... I'm sending my head to Motorrad for a little work... Then install the new modded gasket.
Time will tell.

So, with the water pump clearance mod and enlarging the inlet side of the clutch cover, here is my temps for today.
70 deg F
42 percent humidity
Breaking in the new top end around town.
Highest head temp 204 deg F
Highest water temp 122 deg F

Average temps
Head 185 deg F
Water 115 deg F

Hmmm.... seems to big of a difference...
I'm taking it back to the shop to re-burp the head, rads, and impeller area just for insurance.

Here is as close as a comparison as I have recorded before:
Air temp 72F
Humidity 43%
Head: 158-162 F
Coolant: 133-138F

Very tool limited at the house but I pulled the burp plug on the left rad and B.U.R.P!!!!
Yeah, back to the shop tomorrow to burp the head, rad, and water pump impeller area..
I bet that will cause the two temps to come back in line..

Head.... B.E.L.C.H!!!!
Temps later today..

78 deg
36% humidity
30-45 mph around town.
Highest head temp 199 deg F
Highest water temp 138 deg F

Average temps
Head 185 deg F
Water 135 deg F

Getting better.
After I get it broke in I'm gonna do some tests with 50/50 green stuff.

The differences between this year at Christmas Valley and last year were as follows.

Bike
Stock engine
Chinese rads
55 pilot 168 main (Too rich)
PC pipe
fmf arrestor

Elevation 4317ft
Last years Christmas Valley temps:
Air temp 100F
The max all time temps were as follows:
Head 224F
Coolant 202F
Average running temps trail riding 2nd to 4th gear:
Head 185-195
Coolant 165-175
50/50 green stuff


This time..

Bike
Semi Stock engine (Stock timing and porting)
Larry modded head (Love my compression release)
Wossner windowed piston
stock rads
41mm carb 58 pilot 168 main (I believe it was really rich, I'll know more in a few days)
PC pipe
fmf arrestor

Elevation 4317ft
Last years Christmas Valley temps:
Air temp 80F
The max all time temps were as follows:
Head 290F
Coolant 205F
Average running temps trail riding 2nd to 4th gear:
Head 260-270
Coolant 145-155
100% Engine Ice

The air temps were 20F cooler but my head temps were much higher then I have ever seen them.
Coolant temps were a little cooler this time over last time which seems right based on the air temps.
I noticed that the head temp was very responsive to throttle usage.. Much more so then previously.
Next I will try 50/50 green stuff and see how it reacts..

Coolant capacity...
Stock is suppose to be 44.8oz
Mine with aftermarket hoses and burping the left rad, head, and impeller area was 45.5oz.
Motorrads system is 56 oz not fully burped...