vt700

Scotch10 · Borekit Bruiser Joined: 16 Sep 2018 Karma :

I have a vt700 shadow.Cannot sort cooling system. Water pump is fine, thermostat tested and fine, fan sensor switch tested and fine, wiring for fan is fine and fan does work. No blockages anywhere so logically it should work. When I test the system following the Clymer manual it just heats up but takes a good 20 mins the fan will not kick in and I end up switching off when first antifreeze comes out of the expansion tank drain hose followed by steam, top and bottom of radiator do get hot. Stumped please HELP!!!!!!!!!!!

jaffa90 · World Chat Champion Joined: 06 Apr 2016 Karma :

Don`t know your bike,
has it got any coolant bleed screws?
Have you tried fitting the rad cap after warming the engine up and topping up?
Have you any water in the engine oil or oil in the water?

Scotch10 · Borekit Bruiser Joined: 16 Sep 2018 Karma :

Its the Honda Shadow VT700 American version of the 750. There is a bleed screw on thermo housing but isn't mentioned in the manual when refilling the system. Cap was on when I did the test and no oil in the system. as I say it does me head in, ive tested the fan and sensor switch both work and radiator does get HOT where the switch fits

Robby · Dirty Old Man Joined: 16 May 2002 Karma :

Two things come to mind.

Rad cap - they can and do fail, so worth replacing.

The hoses to the expansion chamber. Are they set up right, and is the fluid in the bottle at the right level (about half full).

There should be a hose from the rad into the expansion bottle, this hose should poke down into the bottom of the bottle, under the coolant. This is so it can push out some coolant in high temperature/pressure situations, then suck it back in when the pressure drops.

The vent/drain hose from the expansion bottle should not be touching the coolant, and exit from the top.

Also, when you first filled up the coolant to get it all bled out, did you run it up to temp with the rad cap open? You need to do that, the water level in the rad drops when the thermostat opens for the first time, and you top it up. If you try to do it with a closed system you just end up with air pockets and trouble.

Scotch10 · Borekit Bruiser Joined: 16 Sep 2018 Karma :

Thanks robby I had the cap on during warmup will try cap off as you say. And I will check expansion bottle I think it's too full can't see through it very well thanks for your help, hope I can ask you for more advice should needs be.

jaffa90 · World Chat Champion Joined: 06 Apr 2016 Karma :

Thanks robby I had the cap on during warmup will try cap off as you say.

Who said that?