BannedCR500Riders.com

Hey guys,anyone know who I can buy a 2 into 1 cooling system head piece for my 98 CR 250 conversion and also need some engine mounts for it too. Cheers !!!

I followed Lonewolf's lead on this one:


CRF450 outlet = 3/4" aluminum elbow

If you look inside the head and really think about it, there is no difference between a 2 into 1 that ends in 3/4", or one 3/4" outlet.

The only reason the CR500 head has two outlets is because the steelie frame and radiator design doesn't allow for a cross over on top.

One 3/4" outlet is actually more volume than two 1/2" outlets.

Just sayin'

Running two outlet hoses (aka stock CR500 cooling path) addes that much more volume to the cooling system...

Buy the Kit for $35 from SolidBro and you are done here is the link:
http://www.bannedcr500riders.com/board/ ... php?t=8553

Make sure that you angle the right spigot if you go this route, learn from my mistake!!

+1 on mounts and headstay

Im doing my 2nd gen 1 (first one ran out of moolah so I sold it) and am more than capaeable of making mounts from scratch but buying them is easy. I like easy

matt_NC wrote:I followed Lonewolf's lead on this one:




One 3/4" outlet is actually more volume than two 1/2" outlets.

Just sayin'

That is some bad math imo but whatever, if you overheat let us know. Honda could have designed the bike however they wanted and yes that means they could have put a crossover thru the frame on the steelies. they spent millions and you've spent?

Pi * r^2

1/2 hole: r = .25 -> r^2 = .0625 -> * Pi = .19635

3/4 hole: r = .375 -> r^2 = .140625 -> * Pi = .44179


2 1/2 in holes = .19635 + .19635 -> .3927
1 3/4 in hole = .44179


3/4 hole wins. Where's the bad math?

MojoScojo wrote:Pi * r^2

1/2 hole: r = .25 -> r^2 = .0625 -> * Pi = .19635

3/4 hole: r = .375 -> r^2 = .140625 -> * Pi = .44179


2 1/2 in holes = .19635 + .19635 -> .3927
1 3/4 in hole = .44179


3/4 hole wins. Where's the bad math?

MojoScojo wrote:Pi * r^2

Friggin Mojo beat me to it....



Area isnt the whole story, you have a boundry layer inside the hose that dosent flow so well, and in the stock CR500 Flowpath, you have a boundry layer in each hose, so the single 3/4" prolly' flows even more coolant than the simple surface area advantage caculation suggests...

Remember though, the water pump is at the bottom, and the radiator inlets are at the top...

Your basically trying to lift a water column about 24" of so, and it takes more head pressure than you might think.

The CR500 pump is a pretty ancient design, and its probably easier to lift 2 .500" water columns from the head to the radiators, than 1 .750" one.

I copied the CR500 coolant flow, and have never had a cooling issue.

Others have gone the 4 stroke path, with similar results.

It prolly dosent matter....

Agreed. It's not all about flow.

Just off the top of my head, 2 hoses = more cooling surface.

Jeff4510 wrote: and you've spent?

More time in a math classroom than you apparently

AlisoBob wrote:
It prolly dosent matter....

All correct, my mistake. I apologize. You are dealing with more than simply size though- there's also pressure but likely not enough to effect this system (I hope).

MojoScojo wrote:Pi * r^2

1/2 hole: r = .25 -> r^2 = .0625 -> * Pi = .19635

3/4 hole: r = .375 -> r^2 = .140625 -> * Pi = .44179


2 1/2 in holes = .19635 + .19635 -> .3927
1 3/4 in hole = .44179


3/4 hole wins. Where's the bad math?

I just spoke to my phd friend (mech eng). By making the hole "bigger" you've lowered the pressure. What's the point of this one line? One less rad hose?

matt_NC wrote:

Jeff4510 wrote: and you've spent?

More time in a math classroom than you apparently