importance of plastic shroud (air cooling the engine)

[xsh0rty]

recently I layed my scooter down thinking i was leaning in on a turn w/ a racebike or somthin.... aka my spree...haha...those skinny bicycle tires... I slid out like a baseball player, skinned the knees and palms, but luckily i wasnt injured, but afterwards my scooter was running like CRAP! It would run up to 20mph no prob then would start to bog out... no power... checked everything! -nothing! Lost a couple hours trying to clean/tweak the carb. Then....dont know why i didnt notice it before- but I noticed the plastic cover that keeps the air circulating around the engine was loose, and cracked....after i fixed it and put on properly, everything went back to normal! I even roll w/o my exterior panels normally because im always tweaking this and that.... and i guess even with the cover slightly knocked loose, air wasnt cooling the engine and i guess i was overheating? maybe soft seizing my piston?

either way i never would have thought it would have made such a difference to tighten the bolts on the fan cover. I went right back up to 30mph.

Anybody else have similar experiences?

[808BMW]

A lot of people take off the shroud to "get more air" to the engine and then seize their motor. The shroud directs air around the fins to pull away heat, very important.

[xsh0rty]

I was so suprised how quickly it made a difference, but now makes me wonder if there are ways to actually ensure more air/cooler air reaches the engine. What about cutting out the small circle where the fan spins to allow more air to run its pattern around the fins but keeping the rest of the plastic in tact. I know it would draw in more dirt etc. but we are always messin around with our scoots i dont think cleaning the fan would be a big deal.

[Arnadanoob]

It's very important. Keeping things cool is a great thing, however keeping temperatures consistent and under control is even several steps beyond that. For example if your bike is hitting 400F+ and all of the sudden you get so much cooling that it drops to under 200F in 10-15 seconds, that's not good either.

Engines can seize at any temp, even cold. Engines seizing from too high a temp is often due to excessive thermal expansion of certain moving parts, in combination with a lack of lubrication. Then there's the kind of seizing that occurs from excessively hot parts cooling too quickly, warping forming irregular tolerances.

[Arnadanoob]

If you ride longer distances, you could think about opening up your airflow to the fan by cutting out some of the grill fins on the shroud, you just have to make sure that you don't accidently suck up a plastic shopping bag or excessive leaves. Some of us modify our shrouds to include a fan scoop.

[xsh0rty]

yeah thats exactly what i was thinking about. Good note about the variety of temperatures. Yep, same reason why you cant put cold water in ur car when ur overheated.

How did you make your scoop? or is it purchased? very cool.

[Wheelman-111]

Greetings:

A-Noob, that is without a doubt the cleanest, best-looking custom scooter/bodywork I've seen on here. Did that used to be an '87 SE50? Magnificent work!

[SpyderMike]

Greetings:

A-Noob, that is without a doubt the cleanest, best-looking custom scooter/bodywork I've seen on here. Did that used to be an '87 SE50? Magnificent work!

my guess is its the canada sb50...is it pal or something

[scooterwerx]

thats an elite e/pal/sb50 with a monsta dio in it! drool what a rad * scooter!

[Arnadanoob]

The bike is built by someone here in Hawaii, I'm just sharing the pics to the shroud's air scoop. It's hard to tell from the pics but it has a stretched motor mount thus longer wheelbase. The fan's air scoop is purchased seperately but you need to cut and shave down the fan shroud to make it fit correctly.

[808BMW]

HMP's ah? That thing is clean, I like the seat.

[GIJoeBob]

Is the shroud still necessary if you are running the scooter with no body panels?

[808BMW]

yes

Only time you can get away with no shroud is when you have no fan

[noiseguy]

Is the shroud still necessary if you are running the scooter with no body panels?

Yes. The stock cast jug is completely inadequate to cool the engine at speed. When the board first started there were a couple of noobs that burnt engines up this way after I'd repeated warned them not to run them like that.

If you want to see an "adequate" design, check out an Express. Big Al fins, and right out front.

[GIJoeBob]

Is the shroud still necessary if you are running the scooter with no body panels?

Yes. The stock cast jug is completely inadequate to cool the engine at speed. When the board first started there were a couple of noobs that burnt engines up this way after I'd repeated warned them not to run them like that.

If you want to see an "adequate" design, check out an Express. Big Al fins, and right out front.

That's kind of a drag as I was hoping to have a naked, painted engine for the next couple of projects I am working on.