|
|
Post by prodigit on Jul 13, 2013 15:09:29 GMT -5
I always double nut my exhaust. I don't know why they can ship scooters with only 2 nuts that aren't even locktited.
It's probably the most common thing for scooters to lose their exhaust nuts!
If you have a 50cc, or sometimes a 150cc too, that's not performance tuned, you can actually use the vinyl sealing nuts.
On the 250's the vinyl will just burn off, and the nuts will fall out when going wot. Too hot I guess. But so far it's working fine on my 150cc. Though I'm not riding it a lot, neither a lot on the highway.
|
|
|
|
Post by prodigit on Jul 13, 2013 15:05:09 GMT -5
It'd almost be like installing a corvette engine on a bicycle.
|
|
|
|
Post by prodigit on Jul 13, 2013 15:04:04 GMT -5
If you want to reduce exhaust heat from the pipe to the engine,
I've noted my ATM50 uses a regular gasket. Those gaskets insulate heat.
However I've seen metallic gaskets, and I've seen copper gaskets.
Those gaskets actually transfer more heat into the engine than the exhaust wrap is insulating the engine from.
Exhaust pipe may be hot, but most of the heat gets transferred via metallic gaskets, not via the air or radiation around the pipe.
Then there's another danger, in if you let the bike sit in rain, the wrap will soak up water, and keep the exhaust pipe wet for a longer time, causing it to rust faster.
|
|
|
|
Post by prodigit on Jul 13, 2013 7:34:13 GMT -5
I wonder if using a bigger exhaust pipe actually causes worse gas mileage?
|
|
|
|
Post by prodigit on Jul 13, 2013 2:23:32 GMT -5
Right, I forgot the pipe has a gasket inbetween that insulates the heat too!  Perhaps try putting a thicker gasket might help too?  There's also heat transfer from the pipe through the bolts/nuts into the engine block, but that should be minor. I believe the fan scoop is responsible for most of the drop in heat in the oil. I personally wouldn't put it on a 50cc 4 stroke, but perhaps on a 2 stroke or a 150cc or up it might prove handy, as usually under 35MPH those scoops don't provide a lot of cooling. On the other hand, cooling down the engine this much, makes it lower performing. Most of the time my scooters perform between 5 to 10% better when they're hot (riding WOT for at least 15-20 minutes), than when they're cold. |
|
|
|
Post by prodigit on Jul 13, 2013 0:25:51 GMT -5
It would be interesting to know if you could plug in a stock pipe, see how it performs as is with a stock pipe, and then just hone down the smalled diameter pipe to be ~1in at the mounts, to 7/8" on the pipe, kind of create a funnel, like in image below; and see how that compares to a 1" diameter pipe!  |
|
|
|
Post by prodigit on Jul 12, 2013 23:13:23 GMT -5
know that there is more heat transfer to the engine from metallic contact, than through air!
|
|
|
|
Post by prodigit on Jul 12, 2013 1:14:12 GMT -5
Sounds pretty retarded to me! |
|
|
|
Post by prodigit on Jul 12, 2013 0:16:16 GMT -5
What kind of gears let go a lot of flakes? I've been working on all kinds of industrial gearboxes for 30 years. The only gears that shread are the bronze helical gears not found in scooters or cars.These gears are all hardened, and a scooter lacks the power needed to wear them out.I dissassembled a scooter transmission at 10,000 miles,No wear on the gears, the bearings were perfect and the oil was as good as the day I put it in. And there were no shavings or flakes.just a litttle darker On my ATM50, and EVO150, there where a lot of metallic flakes in the transmission. When the gears are first used, a lot of the teeth need to settle in, burrs chip off too. |
|
|
|
Post by prodigit on Jul 11, 2013 23:53:07 GMT -5
I think it could also be rich.
Easy cold start is signs of being rich.
Dying on hot is signs of being rich.
Same principle as a choke. You RICHEN the mixture at a cold engine, and it dies when hot, when the choke is still pulled out or enabled.
|
|
|
|
Post by prodigit on Jul 11, 2013 7:58:01 GMT -5
I presume it is possible on some bikes, with heightened needle, that the needle is fully out of the jet at that 80% level, and you are only getting faster because of the increase of air (running leaner), but not fuel (as it's already maxed out). It might be a possibility too.
|
|
|
|
Post by prodigit on Jul 11, 2013 7:54:52 GMT -5
I think the radiating is a lot better than trapping it. The metal pipe will get hotter, and a lot more heat gets transferred via metal than via air to the engine...
If you ask me, it's working counterproductive.
I know they do it in cars sometimes, but that's only because the majority of the air in the engine compartment is not moving or circulating very fast. With a scooter, the air goes over the pipe almost always, unless you're standing still, or riding with the wind at the same speed as the wind... my 2 ct.
|
|
|
|
Post by prodigit on Jul 11, 2013 5:50:59 GMT -5
Why the wrap on the exhaust? It only traps the heat?
|
|
|
|
Post by prodigit on Jul 11, 2013 0:02:33 GMT -5
Perhaps it is possible to file off the exhaust pipe edge (the wall you describe) to make it more like a cone instead of a wall? I can certainly see how the pipe would heat up part of the engine more, not a problem in most cases, unless you're riding in the desert, or hot climates (say, above  degrees). |
|
|
|
Post by prodigit on Jul 10, 2013 23:54:42 GMT -5
Gear oil usually lasts for 3k miles. Though the first oil change should be done before 300 miles, as the gears let go of a lot of metal flakes in the beginning. I use 75W90 or 80W90 gear oil. 80W140 is not better oil, it just has more additives in the oil; and since you change the oil not because of pollution, like what happens to engine oil; but you change it because of wear; it's better to get the first number up as high as possible (80) for better lubrication and longer oil consistency, and the second number as low as possible ( ) for less additives, and less resistance, and better MPG. The gearbox is pretty much a closed compartment, unlike the engine, so gear oil additives can last for years, if not a decade, without wearing out the additives; unlike an engine that constantly sucks in oxygen, and blows out carbon, heats up high temps, and sometimes allows humidity/water damp to enter into the engine compartment via all the cracks and nooks of the moving parts. 85W140 is better for heavier bikes like 250's. For a 150, the 80W90 is good enough. For a 50cc the 75W90 might be better, but should make almost no significant performance improvement. A bottle of gear oil costs you $6 $15 per bottle, and is good for ~2-3 oilchanges, or ~10k miles! |
|
degrees).