Thread: Engine warm up
View Single Post
Old 07-14-2014, 02:51 PM
rackemblue's Avatar
rackemblue rackemblue is offline
Motorized Bicycle Senior Member
Join Date: Jan 2014
Location: Orange,Tex
Posts: 72
Default Engine warm up

For those of you who do not know the importance of letting the engine warm up for five minutes before takeing off on your bikes for the first time of the day or night. This information I learned in Motorcycle school. The pistons in all bikes are slightly cone shaped smaller at the top than down at the skirt. The reason for this is the top of the piston is going to expand more from the heat on top from all the little explosions of repeated fireing. After they warm up they are steight up and down on the walls from the top to bottom of the piston. The cylinder and head of aluminum also expands and contracts on their respective gaskets. So if you take off before they have expanded your piston is rattleing at the top from being loose in the cylinder and oils and compression can leak from your gaskets. That is what causes the most engine failures or excessive wear and blow by from your head gasket and base gaskets. Harley found this out the hard way when they went from the iron heads and cylinders to the aluminum Evolution motors. We had to change out many cylinder base gaskets and head gaskets under warranty. They were blowing oil every where. They then started changeing gasket material and looking for why until they realized how long it took to warm up and tighten up on the gaskets. Takeing off with a cold motor puts crank case pressue on gaskets and causes them to leak or blow out.
Reply With Quote