As soon as you crawl out of bed tomorrow morning, try this experiment: run outside and sprint down the street. Aside from embarrassment over your jammies (or lack thereof), how do you suppose you’ll feel?
Your motorcycle likewise needs to warm up a bit before hitting the street. Many of the people around AMSOIL love anything to do with an engine, including motorcycles. So to get the technical details explaining why, I consulted a few of our resident bikers.
The heat is on
Metal expands when it’s heated, and anyone who’s sat astride a motorcycle knows they make serious heat. Subjecting a cold piston to extreme heat and friction without first allowing it to warm up can cause rapid piston expansion and scuffing.
Here’s what John Skuzinski, our mechanical test development manager, says:
“Optimal parts clearances inside the engine are not achieved until normal operating temperatures are reached. If clearances are less than normal due to low engine temps, and the throttle demands the engine goes to work spontaneously, internal temperatures can rise very rapidly. Most frequently the pistons will heat-up and expand well ahead of the cylinder bores. The chances of clearance-related scuffing and seizure are thereby increased proportionally.”
Translation? Something might break.
Our director of facilities and maintenance, Rollie Everson, agrees. “I like to get them [engines] warm before putting any type of stress on the mechanical components. This makes sure components expand at a gradual rate when they are cold.”
Go with the cold-flow
Another reason to warm-up your bike is to circulate the oil. Here again John Skuzinski has some great insight. “Cold oils inhibit pumpability and flowability, making it more prone to thin-film and hydrodynamic-wedge breakdown. Under extreme cold-oil conditions, it is possible that the oil won’t be able to flow into the oil pump, leading to bearing and journal damage and wear.”
Translation? Again, something might break, this time due to lack of oil.
Of course, a good solution to poor cold-flow is to use a high-quality synthetic that flows quickly to engine parts despite cold temperatures. AMSOIL laboratory chemist Dale Beck explains:
“The highest chance of wear should be under the initial startup when the oil has yet to be circulated to all the components in the upper end. AMSOIL motorcycle oils have very good pumpability at cold tempatures, definitely colder than I enjoy riding the bike at, so I don’t worry much about the oil not being circulated enough. Our oils also have very good protection for cam wear, relating to initial startup, so unless you are redlining the engine after startup there shouldn’t be any worries about other engine parts.”
How long should you warm the engine?
Everyone I talked to said about one minute is plenty of time to allow the piston and other parts to gradually expand and ensure good oil circulation to the upper end. In fact, most riders just start the engine and then spend a minute or two putting on their helmet and preparing to ride. Once they’re ready, so is the bike.
Rollie Everson: “I only warm it up for a few minutes. Just enough to get it to a low idle.”
Patricia Stoll, AMSOIL trade show manager: “I warm mine up so I know everything is running well. I usually do this while I put on my helmet and make final adjustments before departing on a ride.”
Jim Swanson, AMSOIL trade show representative: “I usually let it warm up while making my last adjustments (ear plugs, gloves, glasses, etc.). This takes about a minute or two.”
Dale Beck: “I would guess that mine only warms up for around a minute. I usually start it just before putting on my helmet and gloves. In my opinion, anything more than a few minutes is a waste of fuel and can lead to deposit formation on the spark plugs and exhaust.”
John Skuzinski: “I like to let temps rise for about a minute before putting the engines to work. I equate it to a little muscle stretching before a heavy gym workout.”
To wrap it up, warm up your bike for at least a minute before heading out. Just use the time to buckle your helmet, slip your gloves on or finish other preparations. That way you’re not wasting time – and you’re likely saving your engine from wear.