Radiators in series........

[Wheelie-Gene]

I was to the point of making up my cooling hoses when I had a decision to make.
I had a choice of jacking around w/making T/Y fittings to splice the hoses together...... or just connect the return hose to the top of the left radiator and have the pump feed come from the bottom right.
That same question has been asked, regarding proper radiator efficiency, with people responding against the idea.
Just for the fact to simplify things, I decided to experiment and go for it. After all, my whole build has been an experiment for me.

The old-style engine.........
We know the issues of using an old cylinder w/the rear coolant feed......the fat expansion chamber interferes w/routing the hose to the back of the jug.

I studied the water jackets and took another gamble in reversing the coolant flow. The inlet feed is to the top of the head, and exit flow is now from the back of the cylinder (turning the L fitting 180*).

I figured the reverse flow will allow the cylinder to have a more consistent front-to-rear temperature. Instead of having a cold area where the coolant normaly feeds in.

Anyway, I've put almost 100 street miles on the bike in the last month. The Vapor unit shows coolant temps to be in the 120* range w/a 70* ambient temp.
The hottest day I've ridden so far the air temp was in the mid 80s, and coolant never climbed over 140.
The strange deal w/the Vapor is it won't show a coolant temp below 100*.
I'll start the bike, and spend time putting on my gear....it takes a blast (an easy trip) up the street to finally get a meter reading.

I made one stop to fumble w/the back pack, dump some fuel in the tank and take time to do a check-over (about 10 minutes) while the bike idled. I noticed the engine temp had climbed to around 180*, but rapidly fell as soon as minimal air flow returned.
I guess my gamble paid off.

I was expcting higher temps, so I'm relieved to see it run so cool (maybe too cool). A far cry from the 480 running an average 300+* head temp.

[AlisoBob]

Interesting stuff Gene....

[CR500R7]

I was only thinking of the reverse flow idea a couple of days ago, you beat me to it.

[asteroid500]

so was i R7
Picturers would be nice Wheelie

[Roostius_Maximus]

like how the lt1 v8 cools

[M.F.D.B.]

like how the lt1 v8 cools

Yeah and its associated air bleed problems...

[100hp honda]

I was to the point of making up my cooling hoses when I had a decision to make.
I had a choice of jacking around w/making T/Y fittings to splice the hoses together...... or just connect the return hose to the top of the left radiator and have the pump feed come from the bottom right.
That same question has been asked, regarding proper radiator efficiency, with people responding against the idea.
Just for the fact to simplify things, I decided to experiment and go for it. After all, my whole build has been an experiment for me.

The old-style engine.........
We know the issues of using an old cylinder w/the rear coolant feed......the fat expansion chamber interferes w/routing the hose to the back of the jug.

I studied the water jackets and took another gamble in reversing the coolant flow. The inlet feed is to the top of the head, and exit flow is now from the back of the cylinder (turning the L fitting 180*).

I figured the reverse flow will allow the cylinder to have a more consistent front-to-rear temperature. Instead of having a cold area where the coolant normaly feeds in.

Anyway, I've put almost 100 street miles on the bike in the last month. The Vapor unit shows coolant temps to be in the 120* range w/a 70* ambient temp.
The hottest day I've ridden so far the air temp was in the mid 80s, and coolant never climbed over 140.
The strange deal w/the Vapor is it won't show a coolant temp below 100*.
I'll start the bike, and spend time putting on my gear....it takes a blast (an easy trip) up the street to finally get a meter reading.

I made one stop to fumble w/the back pack, dump some fuel in the tank and take time to do a check-over (about 10 minutes) while the bike idled. I noticed the engine temp had climbed to around 180*, but rapidly fell as soon as minimal air flow returned.
I guess my gamble paid off.

I was expcting higher temps, so I'm relieved to see it run so cool (maybe too cool). A far cry from the 480 running an average 300+* head temp.

changing the flow is cool idea. ktm did same thing on all their big 2strokes, worked almost too good. i didnt change the flow on mine but im using a o-ring head with no jacket restriction and using a thermostat to regulate the flow rather than the head gasket. thing i dont like about that head gasket is it restricts flow 100% of the time regardless of temp, thermostat will only restrict flow as it sees necesarry.

[Wheelie-Gene]

I had thoughts of installing a t'stat, but summer days will be here soon and cold weather riding won't be a factor.
If coolant temps are in the 180* range, I won't worry about it. One less part to fail and less to clutter things up.

Did you make some sort of pressure by-pass system?
Any pics of your set-up?

[M.F.D.B.]

Any pics of your set-up?

Dude, what kind of rims are those in your avatar?

[Wheelie-Gene]

VFR in the rear and RC51 front.
CBR600F-3 parts on the thumper.

There's a build thread here somewhere on the 500.



.

[M.F.D.B.]

Did you fab that gull arm? There are mucho better looking headlights than that one you have, but the bike looks badass besides that!

[Wheelie-Gene]

It started from a donor unit.

.


Had one of the Acerbis cyclops light kits, but it was cheezy and wouldn't fit the forks......and the low-wattage stator wouldn't have been able to power the thing.
The headlight on the 500 was originally on the thumper. I recycle what I can, when I can
It has a low-wattage bulb (modern Chevy blinker bulb) for daytime running, and enough to pass for the inspection sticker.

The little fairing is a nice place to conceal the ignition switch and the Vapor unit, but yeah......I was in a hurry to get it legal. If I find something better, I might change it out....but then again, maybe not.

The bike is 99.9% finished, and I moved on to other projects. If I make any changes it won't be for a long time.

It is what it is.

Thanks man............