Gilera Runner VX 200 Overheating

Temp gauge goes to red within 5 mins of idle from cold. I changed thermostat and still the needle goes to the red. Cylinder head doesn’t feel baking hot though when I feel it.

I also upjetted main jet from 118 to 122 and adjusted mixture screw encase it’s running lean.

Also flushed system through with hose

could it be temp sender?
How can I check water pump works fine?
Also there is no bleed nipple for coolant system, how do you bleed on these engines?

 

It's tricky but you should be able to see the water being jetted back into the expansion tank in the neck of it.
Loosen the temp sender so that the bubbles come out there, then tighten it up once done
Check the colour of the oil to make sure it hasn't gone milky, if it has, gaskets gone.

 

UPDATE - STILL OVERHEATING - VERY FRUSTRATING


Water isn't being jetted back into the expansion tank. Only If I squeeze the 2 hoses that are connected to the water pump housing, then I see it squirt back into the neck of the expansion tank.

Checked oil dipstick and had a look in the sump, and no signs of milky residue.

New thermostat, new temp sensor and new radiator fan switch replaced today and still overheating. The radiator fan doesn't even kick in and I've put 12v across it and it spins fine. CONFUSED.COM

I adjusted the float height today to make the carb run richer, went up 1 on the pilot jet and a 120 main jet.

I seem to have covered most avenues apart from water pump. Could the water pump be knackered?

Any help will be hugely appreciated, I need to get to the bottom of this lol.

 

So today I inspected the water pump which seemed to be fine. No evidence of leaking or broken pieces.
However I took the coolant hose off which goes from the pump housing to the cylinder barrel. Looked through into the barrel and could see small amounts of gunk. Which appears to be a jelly type coolant. See pics attached.






Going to take head and barrel off this weekend and replace head gasket and give everything a good clean. Hoping this cures the overheating issue.

 

Jelly like substance in the4 coolant says that different types of anti freeze have been used and reacted with each other, forming the jelly.
Although you have already flushed the system, you will need to do it a lot more.
reverse flush the radiator, all the hoses, everything connected with the water flow, even the small loopback hoses and the ones that go to the bottom of the carb.
ABSOLUTELY EVERYTHING........

 

What hose do I send the water through to reverse flush?

 

All and any hose or water connection, barrel, (take stat out first) rad etc. I'd be tempted to use a high pressure washer to blast through the barrel VERY CAREFULLY !!

 

Does the waterpump pump water if you disconnect hose to barrel while running ?

 

Thanks for the replies, I will try tomorrow and see...

 

Ive decided to replace base gasket and head gasket today. Im slightly confused to where the 4 small 0-rings fit. I was aware you slide them down the studs and they press into the holes on the cylinder and then the head gasket sits ontop? I can't see 2 of them fitting in 2 of the holes as the o rings seem slightly too big for it, however they will slot into the other 2 holes with the dowels fitting ontop.

When I lifted off the cylinder head, they were sitting ontop of the head gasket. Can someone please confirm where they go?

 

I was referencing the following YouTube clip at 1:10:39

 

The O rings sit in the head gasket, you'll see 2 bigger holes round 2 studs.

 

Yep I see that. And the other 2 O Rings.... sit within the gasket also but slightly proud?