Modern Vespa

So I have been riding my LX50 around, having a lovely time. I know that after we get to the top of a long hill I can feel some heat under the seat cushion. While I wait for my partner to get to the top of the hill on her bicycle I shut the Vespa off, and remove the pet carrier to let some of that heat out and help cool the engine a bit.

Am I being silly in doing this? Do these ever overheat?

Yes, it can overheat if the cooling fan or shrouds are damaged. However, in your case it sounds quite normal. In my opinion it would be much better to let the engine idle while you wait so the fan can keep the engine cool. The heat that you see under the seat is normal.

Bill

I find it pretty cool that as I was reading your response my spouse is in the next room playing clawhammer banjo!

Ditto, Bill

I overheated my LX once. It took a 140 mile ride in temps from low '90's up to 108 to do it. Don't worry, you'll be fine.

Haha, good catch on the banjo peg head Troutgirl! I play frailing on a Wildwood and grew up in eastern Mass. Small world. Oh, and ride a Vespa.

If it is a four stroke, you could add an oil cooler. If you dont hear pinging or increased valve noise, your engine is probably running cool enough during those climbs.

Is there a fan on the LX50?

Yes.

Thanks. I didn't think of those fans. I was thinking about the fans that operate on the water cooled engines. My bad.

Last year i over heated my LX 150mas well. I was over heated also. It was a rare day in the high 90's. No wind and bumper to bumper traffic, with 100% humidity. I was in the Pearl City area. Took me a hour to go 4 miles. There are a lot of concrete high rises and the road is 4 lanes of traffic. Because of the damn rail their building people are forced to use this road. I had cement buildings all around me and cars and trucks between me (i was in the center lane). My scooter started to cut out. The cool thing is i met this cool guy on a moped and we stopped for a drink on the way home. We both let our scooters cool down and we cooled down with some nice cold cokes with water chasers. To bad he was so young. First time i've ever had a scooter over heat but it had to have been that because the bike was fine when i got out of there closer to home where it's always cooler. Scared the crap out of me.

My S150 blows hot air from the start. The magneto fan and shroud seem to be okay. I tseems to be directed towards the inside of my left ankle. When I changed the tire I looked to see if anything was wrong but all seemed fine. Question:

The magento 'fan' is suposed to blow air in, isn't it? Like into towards the magneto?

@ Max6200: Yes. It draws air in and forces it past the cylinder's cooling fins through the shroud. The air heated by the engine then escapes under the bike (hence your warm ankle).

The following ONLY applies to air-cooled (LX series, Piaggio Fly, etc.) bikes:

If you need to cool the bike down after an extended high-speed run or whatever, consider putting the bike on its centerstand and revving the engine up. The additional airflow from the fan spinning at higher RPM will far more than overcome any additional heat from burning more than "idle" fuel.

Two cautions: First, the bike will "walk" (slide around) on the stand due to vibration -- you may want to keep the RPM below where this happens, or just hold the front brake to minimize how far the bike wanders. Note that the centerstand will likely leave nifty scrape marks on the pavement in the process. Second, when you're done use the rear brake to stop the rear wheel if you're taking it off the stand again immediately, so you don't launch the bike.

You can do something similar on a 2T classic Vespa, but since the rear wheel isn't raised from the ground by the centerstand, you need to have the bike in neutral, the clutch lever pulled, or preferably both. (This assumes that you trust both the clutch cable and the transmission's ability to stay in neutral...) If circumstances permit, it's probably simpler to ride around for a bit near the top of first or second gear without much throttle.

Why not just turn it off?

Probably some experimentation is needed to validate our statements.

I assume the engine is really hot from long hill climbs and high summer temperatures. Also I assume that having a fan on the motor when sitting still is better than no fan. This gives better convective cooling rather than mostly conductive cooling at the fins, especially with the fins inside a plenum. So probably it would be better to shut off a typical air cooled motorcycle with no fan if you are going to be stopped for a while.
Also, idling means the motor oil is pumping to help move internal heat from the hot spots.
I am not sure that reving up the engine is helpful, though.


Bill

It can over heat like i said above. I don't think that it helps much by taking out the pet carrier. Maybe doing that along with letting the bike cool off for a while. When mine over heated it sat for 30-40 min (didn't take the pet carrier out). I think the metal body traps the heat in. My Vino's (plastic bike) doesn't get a hot at all under the seat. MY LX keeps food warm. I would say the heat around me was about 10 and i was sitting in traffic not enabling any "cooler" air to be sucked in by our small fan. That doesn't help very much.

Underlined for emphasis. Very much so if there isn't forced-air cooling, and in that case revving the engine makes things worse.

With forced-air cooling, revving up the engine should be a significant help, as the airflow at any given RPM ought to be adequate to cool the engine under load at that RPM; unloaded, that's a lot of excess cooling capacity.

I never had an overheating situation but I wondered if removing the spark plug access panel would aid cooling?

I think it would add some relief but I don't know just guessing.

because the gas is a coolant when running. use do this a lot when riding dirt bikes in the 70's and come out of a long woods section. we use to use the manual choke to help cool the cyl while riding slowly for a half mile before opening it up again.

learned the hard way once when I came out of the woods and just let er rip and a half mile down the road it seized big time. wound up breaking the cyl skirt and dropping a bunch of bits in to the crank cases. that ended my day and a DNF.

No, if you remove the spark plug panel the incoming air will not run through the full cooling circuit. If you are idling in heavy traffic, overheating and not moving, as in Judys case, the best thing to do is what she did: shut it off and let it cool down. If you have just come from an high speed run, like the highway, and you are pulling over, it is best to let it idle a bit as the circulating oil will help it cool down as well as the fan. Reving it will just bring the temp back up.

Was this a 2 stroke bike or 4 stroke? If 2 stroke, I can understand this method. In a 4 stroke, gas will not cool it down much of all, if any. In a 2 stroke, the point is debatable. Jet it right , timing set good and you will have no problems.

2 stroke,

as far as jetting it right, what would you jet it for? woods, i.e. slow quick bar banging or deep power robbing mud, or higher speeds of roads? oh and don't forget water crossings, long dirt hill climbs all over the course of 100+ miles.

Stopping to change jets in the middle of a race when minutes matter sometimes seconds, ain't happening either.

Old, I guess I was thinking more of a road two stroke bike. I did some enduros in Florida growing up and it was always a challenge to getting the jetting right. Down there it was some wet areas, but mainly, sand, sand and more sand. Hot as hell, especially in full gear, but you did not have to worry about mud clogging up your cooling fins. I will say I was in one race, doing really well, just came out of a heavily treed pine forest(for Florida) and hit a wide open field with the finish line ahead. I hit the throttle hard, holed the piston and drifted across the finish line barely winning. But still losing, because it was my buddys bike and I had to pay for a new piston, rings and hone. All I needed to do is run a little choke. Lesson learned.

I will add too: water cooling those two strokes made a world of difference. A lot easier to jet. Of course, then you have to worry about getting a hole punched in the radiator.