letting the engine rest?

Hi

well the other day a friend writes that for every 1hr of use on a scooter you should let the engine rest for 15 min. I reply by saying, does a Tmax really need 15 min break after only 1 hour? or a silver wing ? So he replys saying "only on small scooters"

So since I don't want to say You are full of it, I ask you if you have ever heard this or it is not true. and why?

Thanks
Damasovi

In my research so far I only found cooling mentioned with respect to running in. Doesn't make sense otherwise - either it is overheating or it is not.

Very extremely rare conditions. A buddy125 bent the crank during a scooter cannonball. Otherwise i think the motors are fine

Must be in the union contract, no?

Regards, Paul

He's full of it.

Its a machine, not a horse.

Letting an engine "rest" stresses it.

What you're doing is letting it cool - contracting the metal; stress. Then heating it back up...expanding the metal, more stress. Better it should stay at operating temperature - especially since probably the total time it will be run in that period will be the same anyway.

If the engine is overheating, it should be let to idle or even shut off...but we're assuming the cooling system is functioning normally and is up to the situation.

I let my engine rest when I'm not using it.

thanks amigos, he did not made sense to me and you confirm it.

Damasovi

Once upon a time, over on another forum, folks who were caught in heavy traffic congestion and had the oil temperature gauge on their oil-cooled boxer engines go up to 5 bars (max) were advised to change the oil immediately.

I do not believe the designer of the engine intended such a rest nor do I believe that a user handbook ever recommended such action. It helps to use the correct oil specified for your climate if you are riding at constant WOT on a 50cc scooter but will probably not destroy the engine if the grade is slightly out.

John

The belief there is that the oil, at those temperatures, would oxidize and gell and clog up oil galleys. Overstated and exaggerated, maybe; but not a bad precautionary practice.

That has little to do with "resting" an engine, however. If an engine is operating out of its design range, the thing to do is take it down back into its range, or shut it down. But for it to just be working...and then shut down for a "rest"...

The longest-lived auto engines are in taxicabs. Why? Because they're hardly ever shut down to cool. Round the clock, they're running...idling a lot, but almost all the time running. What happens?

Back around 1982, I worked for a small cab company that ran Ford Granadas with six-cylinder engines. And those engines would last for over 500,000 miles. What generally killed the cabs was either rust or an expensive transmission failure. But by NOT "resting" those engines, they lasted five times as long as ones used in personal cars.

They were always warm and the engine always lubricated. No cold, dry start-ups.

Back in the late 70s a group of us decided to run a Vespa 200 for 72 hours without shutting it off, putting on as many miles as possible. We rode in 6 hour shifts and put on over 3500 miles with no trouble whatsoever. Riding down the highway at 3 am in the fog wasn't a lot of fun though.

Why would you want to remove the condition for which an engine was designed - heat? A cold/cool engine is out of it's design parameters which is why there is a thermostat on them (the liquid cooled ones anyway). Even my air cooled Karmann Ghia motor has a thermostat - it helps to get the engine up to the operating temperatures for which it was designed for. Without that feature it would run like crap and in cooler climates the oil would never get warm enough to expel moisture - nor would it lubricate efficiently. Oil is designed to work best at about 200F.

MAYBE if its super hot, and its an air cooled, once in a while. But thats under extreme conditions.

But otherwise I'd say its unnecessary, unless as others said its overheating.

But I'd agree you don't need to do no such thing, espically on a liquid cooled motor.

Over the years, I have run across specs for diesel engines on how long they should run at full power, and I think there was once a suggested length of time for full power on Royal Enfields.
When in doubt, read and follow the recomendations in your owners manual.

I would agree with the "run them" school of thought. I ran long haul trucks for years. Now a 14 litre diesel engine is a different animal from a 50cc scooter, however the principal is the same.

When a truck is loaded and trucking, the engine is under significant load for many hours if not days. Even on flat straight roads, a stiff wind will have the engine pulling 80-100% of its load capacity, and I have seen many with well over 500 000 miles.

I also have a diesel pick up truck, and notice a big difference between after I have gone on a road trip with my trailer vs. driving around town empty. It runs better and pulls stronger after it has been worked.

Unless something is causing the engine to run hotter than recommended I would carry on. Your engine will thank you.

I used to worry about my chinese gy6s but then got to watching some kids on a gy6 gocart and decided if they could run two tanks of gas out without more than a fuel stop I wasnt hurtin the scoot.

Maybe they meant that YOU need a rest after an hour on a small scoot.....I know that was about my limit on the old 150.....not the silverwing though.

Thats strange how you says that they pulls stronger after they's been worked.:huh Is that a temporary effect?

1. self learning control units (with advanced fuel injection, not carburetor).
2. hard load cleans engine+exhaust.

Some air cooled aircraft engines should, or are better off, "resting" after running, especially ones with fuel injection and turbo chargers. You let the turbo spool down at idle for 1-2 minutes before shutting it down, lessens the possibility of the oil coking in the turbo. Starting it right up after shut down (if it doesn't vapor lock) and taking off on a hot day, you're more likely to have temperature issues, oil, egt, and cylinder heat issues. At least one turbine engine I've operated required spinning the starter or pulling the prop through by hand to get cooling air back into the engine - reputed to, over time, bow the shaft, if you didn't do this. The engines weren't back alley junk, they often lasted 7000+ hours.

Aren't we discussing scooters?

(Also, FI doesn't vapor lock...carburetion does)