DRZ400SM - weirdly routed radiator hose?

[Hugh Dick]

This cant be right, right?

I was looking at these pictures of my bike.

From top right of my radiator, goes the radiator hose. It goes front, then in and around the fork (the center thing behind the light next to the throttle cables etc, not around the fork legs), then continue in on the left side of the bike, between the carb and frame (obviously not its original place since it a bit pinched), then goes down into there.

Also, on the other side, I noticed a similar hose. I think this might be the exit back to the radiator.

Hose looks lika a generic aftermarket radiator hose, retro fitted ghetto style and routed in a way I don't fancy. It just feels bad man. How is it supposed to be routed?

Gonna fit a fcr there soon, need space.

Regards,

[HansLanda]

Do you still have your overflow tank by your left footpeg? Looks like they are heading there. If you want to eliminate this excess hose and clean up the look, you can search for the "Turkey baster mod." It relocates the overflow tank to a small canister most people zip tie behind a radiator.

[thnksno]

That's an awfully big hose for the coolant overflow. Are you certain that has nothing to do with Euro-emissions?

I cannot recall exactly how the overflow is routed, but it's no bigger than the fuel line to the carb. It comes into the tank from underneath the engine I believe.

Whatever those hoses are, that one over the carb will give you fits when you try and install the FCR. Outside of the coolant overflow line in and then overflow line out, I see no reason for ANY coolant hose to be south of the cylinder unless you bike is fitted with some sort of heat exchanger for additional cooling under the rear fender.

[Hugh Dick]

1 hour ago, thnksno said:

That's an awfully big hose for the coolant overflow. Are you certain that has nothing to do with Euro-emissions?

I cannot recall exactly how the overflow is routed, but it's no bigger than the fuel line to the carb. It comes into the tank from underneath the engine I believe.

Whatever those hoses are, that one over the carb will give you fits when you try and install the FCR. Outside of the coolant overflow line in and then overflow line out, I see no reason for ANY coolant hose to be south of the cylinder unless you bike is fitted with some sort of heat exchanger for additional cooling under the rear fender.

Yea I see no reason either, I had another look, and at the exploded view of radiator system, I think indeed it is the coolant overflow. I suppose I need to order a new radiator hose kit which seem to include the correct hose (pic)?

[thnksno]

Are you 100% sure it connects to the overflow bottle and not the air boot?

The overflow bottle is a small hose diameter. Before you order anything I would undo the hose completely at both ends. Then you should be able to measure the coolant overflow barb and go to any parts store and get a section of hose. Cut it to length and install it.

I'm baffled by the diameter and the routing. It should be kinked making that 90° into the coolant overflow bottle from where the carb is.

[Hugh Dick]

2 hours ago, thnksno said:

Are you 100% sure it connects to the overflow bottle and not the air boot?

The overflow bottle is a small hose diameter. Before you order anything I would undo the hose completely at both ends. Then you should be able to measure the coolant overflow barb and go to any parts store and get a section of hose. Cut it to length and install it.

I'm baffled by the diameter and the routing. It should be kinked making that 90° into the coolant overflow bottle from where the carb is.

Good advise, I will check before hand. If I remembers, I will take pictures just for the fun of it. I am pretty sure it is not connected to the air boot, that connector is occupied by a short hose that I removed and re-installed while I had my carb out - can't remember where the other end was (carb?).

If anyone have diameter and length of a legit overflow hose that would be great! Preferrably both inner and outer diameter but either should do =)

Edited April 19, 2017 by Hugh Dick

[thnksno]

I went and looked at mine real quick, it's factory never rerouted.

A 12mm wrench slips over it. It is routed up the middle of the cylinder to the right of the manifold, on the bike looking forward. From there, I dunno, maybe I'll look next time the tank is off. You should be able to find hose +/-12mm OD and just measure the OD of the barb for the +/- of the hose ID and get something close. It's not a critical part under pressure, it just guides coolant overflow to a reservoir. While I haven't tried it, nor necessarily recommend it, many ditch the reservoir altogether and let it drain to the ground. When the radiators are hot, they purge the excess due to expansion, when they cool they are short, which is the amount needed for expansion. Overflow bottles are also known as expansion tanks. Mine burps a small amount of coolant when hot, but sucks it back in when cold.

[Melkor]

Do you have a hose hanging under the bike behind the swing arm and in front of the rear wheel?  this would be the expansion tank overflow and the radiator overflow hose is the same diameter.  There is no pressure in this hose so any type of heat resistant hose will work.  It does not have to be a large hose,  there should only be a small amount of coolant ever leaving and entering the overflow

the hose should route from the nipple on the radiator near the cap, down the right side of the top frame tube and then cross over to the overflow tank and connect to the bottom of the overflow tank.

 

take a look at the fiche it will give you an idea of what is what.

 

 

 

[Beta300REcat]

The overflow hose has a shield around it. Looks stock like mine.