I just got this dirt bike and the boy changed the head gasket and he ran it and he then noticed it was not running right. So this should mean it is a blown head gasket correct? He thinks he did tighten it up to much when he put it on. SO does this mean if i change it it would be fine? Also does it running rough mean the head gasket is blown?How do I change head gasket on 1989 yamaha 125cc dirt bike?
Why did he change the head gasket in the first place?
That engine is water cooled - if the head gasket was blown, it would leak coolant out of the cylinder, or the compression of the engine would be blown into the cooling system and blow the coolant out of the radiator cap.
The head gasket is the least of your worries.
Bad gas or incorrect premix ratio.
Dirty air cleaner.
Dirty carb.
Worn out top end (cylinder, piston %26amp; rings).How do I change head gasket on 1989 yamaha 125cc dirt bike?
man, so many answers to this question.
First, do you have the tools and skill to do the job. Have you ever removed the heads on a bike before. Do you have the equipment to determine if the head is actually warped now or not, and the machinery to fix it if it is? Do you have the shop service manual on the bike so you know what all the correct torque settings are for the head bolts.
Do you know how to set the timing and what the specs should be when you get the heads back on. Do you know how to adjust the valves.
Bottom line, could the problem your having now be the heads? Yes, it could also be any one of a dozen other things as well after having the heads removed. If the guy THINKS he might have over tightened then that tells me he didn't use a torque wrench or go by the specs, which means he probably didn't go by the specs for anything else.
If this is a bike you really want to ride, take it to a shop and let them figure it out, you can permanently mess it up if you don't even have the basics like the shop manual and proper tools, to say nothing of the skills.
