Vmax540
VIP Member
Since it needed crank bearings I had my 1990 Exciter rebuilt from top to bottom by the local Yamaha dealers head Mechanic (35+ years experience). Rode it 4 miles and it started to lose power and bogged then stopped. I opened the hood and had to give it gas to keep it from shutting off and I could hear the antifreeze boiling in the Head/Cylinders, the water was circulating thru the heat exchangers and hoses and didn't seem overly hot to the touch. No over temp light but, the sensor is on the neck where the pressure cap is and that area like the rest wasn't hot like the engine definately was ! After it cooled down I drove it back to the house less than 1/4 mile away and then the head gasket was seeping. Pulled the cylinders and found brownish antifreeze substance(?) in the bottom of the crank case. Now look at the pictures should the base gasket on the front side (exhaust) be open between the cylinders and crank case for antifreeze to flow ? There was a greenish slimy antifreeze goo susbstance on the base gasket exactly where the water ports line up ! Thanks for any help !
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nightmanx1
New member
the Manual I have does not show any holes in it but then I could be wrong. I went to a Yamaha web page and here is what i found. http://www.prosourcemotorsports.com/fiche_section_detail.asp
And it looks like there are holes. For the 13 bucks it is going to cost and since you are going to need one, get it and find out.
And it looks like there are holes. For the 13 bucks it is going to cost and since you are going to need one, get it and find out.
Vmax540
VIP Member
toydoc
Member
That wont be the cause of your problem. But the 1987~89 had a rubber plug in the bottom and no holes in the gasket. 1990 and up came with the rubber plug removed and holes to the case.
It may have had air in the system, or a bad water pump or thermostat..
It may have had air in the system, or a bad water pump or thermostat..
Vmax540
VIP Member
Interesting Why would the earlier Exciter ports be blocked off ? I will check the thermostat but, would it be ok to eliminate it all together ?
toydoc
Member
Vmax540 said:
It's a "dead" area in the cooling system anyway, so it wont do much pluged or unpluged. Waaaay back when I use to do mod exciter motors, I'd remove the plug. Then I'd drill and tap a inlet in the head and that cooling area of the case. Then run a "T" and coolant lines to make coolant flow around the exhaust port. None of that is needed with a stock or mild exciter motor.
I'd keep the thermostat. Just test it with a pan of HOT water and make sure it opens.