Top Speed - SH150i

[JetPilot]

What is your guys top speed on the STOCK SH150i scooter ????

In order to get a good average, please post only FLAT GROUND, No wind, no drafting, top speed with no external factors increasing or decreasing its performance. I can get a bicycle up to 70 MPH going downhill, so that kind of information is just useless and confuses the issue...

I ask because on my 2010 SH150i, with only 800 miles on it, maximum rated air pressure in tires, 200 pounds weight rider and gear, I get only:

62 MPH sitting up normally.

68 MPH in a full tuck, out of the wind, body and shoulders behind the windshield.

Mike

[TommyXP]

Personally, between 65 and 70mph on 2 SH's with full windscreens. I noticed it varies according to temperature, atmospheric pressure and humidity too.
Try the "Search" function, as I recall some highly detailed posts including graphs and mpg.

[stonerolled]

stock with full honda windscreen and trunk installed...
Mine will hit about 68 mph under flat windless conditions.
Add high speed traffic drafting and its 70mph.
Up an overpass with adverse wind can still count on 60mph.

[SWDan]

Put me down for 60 - 65 depending on conditions and I'm a big boy.

[luxroller]

Mine (2011) does over 120 Km/h = 75 miles on the speedometer.
On topspeed my SH gets instable on the frontwheel ( now the steering-bearings are stretched, before it was impossible to drive at topspeed).
Toni

[JetPilot]

Mine (2011) does over 120 Km/h = 75 miles on the speedometer.
On topspeed my SH gets instable on the frontwheel ( now the steering-bearings are stretched, before it was impossible to drive at topspeed).
Toni

Wow, that is REALLY DANGEROUS. You should get that fixed ASAP. If you get a wobble, you will probably crash at 75 MPH. At 68 MPH, mine feels perfect and stable, the only way I feel the speed is to look at the speedometer.

Also check your tire pressure. Low tire pressures can make instability even worse. How many miles do you have on your scooter ??? Bad steering bearings are really dangerous it will wobble and throw you off the scooter quick !!!

Mike

[JetPilot]

Mine will hit about 68 mph under flat windless conditions.
Add high speed traffic drafting and its 70mph.
Up an overpass with adverse wind can still count on 60mph.

Wow, everyone seems faster than me I am going to have to stick a GPS on my scooter and see if it is really slow, or if the analogue speedometer is just inaccurate...

Mike

[luxroller]

The steering bearings are ok but when i got the bike (new) it was far too loose like on many many SH. Before tightening the bearing riding at topspeed was like a suicide. Tire pressure is ok. I guess the front fork is not of good quality but i can live with it.

Do you have a new model ? I may be wrong but i thought the non-abs models have one horsepower more. Maybe thats the difference


https://flic.kr/p/CmKcZg

Toni

[TheLogo]

Again! So happy I came back to the boards.

THis was my scooter. Stock, flat, no wind, i might see 60.

I got mod's galore now and get to 70.

[robber57]

Hello to all new users!

i am Richard the admin and nowadays not often here as i am still recovering from a meeting with a Ford transit van on my (now totaled) SH, currently i am in the process of veeeery carefully riding 5 minute errants on my sh300, the 2006-150 will be replaced by another one.
But i have good days and this is one of them

an sh150 will top out at any speed depending on the state of your drive train and tires.
it is designed to go at max speed without using the full 100% of all horsepower available, so effectively it is a bit under-geared like most motorcycles, this saves the clutch and gives better acceleration and less fuel consumption, in other words it makes it more efficient for every day use but you wont be able to squeeze every last mph out of it.
"under-geared" is like driving in 5th gear while you have 6 available.

lets make an example with random values: at aprox 8750 rpm the climbing hp graph comes to its maximum at 16 HP and then starts falling again if rpm goes any higher.
At that 8750 rpm it will go 68 mph and only use 15 HP(of 16 HP available) and will not go any faster because to go any faster it will need more revs but at over 8750 rpm the hp is falling down so it will not go any higher in revs unless you are going downhill.
If the engine is running at max HP rpm it will not mean that it is also delivering full HP, it will only deliver enough HP to keep the speed associated with the rpm, or in other words; it will only deliver the HP that the total drive train is ASKING from the engine, if at 8750 rpm the speed is 50 mph it will only need 10 HP to do this so only 10 out of the 16 will be delivered.

But if you would install a tire with a slightly bigger circumference you will be able to use all of the 16 HP at 8750 rpm and accordingly it will go over 68 mph.

That means that the topspeed of an sh is depending on the TOTAL transmission RATIO.
Transmission ratio explained:
If you have 2 gears, one 15 teeth and the other 30 and the 15 teeth wheel turns at 1000 rpm the 30 teeth gear will revolve at 500 rpm, thus the transmission ratio is 1000:500 or 2:1.

The total transmission ratio is a calculation made from ALL the things in your scooter which transforms the crankshaft rpm to the rear wheel rpm meaning the multiplication of vario-ratio X final transmission ratio and added to that comes the wheel circumference as that is the device that transforms rpm to road speed.

this means that whatever wears down in your scooter that changes the transmission ratio will effect topspeed.(so this is different from a normal gearbox motorcycle as all the gears and thus the gear ratio in a normal gearbox are FIXED, the only thing that can wear is the rear tire)

So that includes the front drive vario, the rear driven vario, the belt, the gearbox which is fixed and your rear tire which becomes smaller due to wear or smaller because you installed a different type/brand.

simply said: if you wear down 1,5 mm thread on your rear tire you will loose 3 mm in diameter and X mph.
If your belt wears 0,2 mm it will reduce topspeed by x%
If your metal vario discs loose x% of material it will go X% slower.
If the vario rollers get flat spots they will have difficulty pushing the vario to its out most point, loosing just a few tenths there means a x% lower topspeed.
and all these tiny little bits add up....

To overcome this i installed a malossi gear kit in the final transmission that increases gear ratio, unfortunately all these kits are just a tiny bit to much which translates on a stock sh to getting a higher topspeed but only with the wind from behind, with the wind up front it will go slower then with the original gears installed, and of course you will have less acceleration from a standstill.
This is what you call "over-geared" and comes down to like driving in a fixed 7 th gear while you would like to be in 6th.
To counter this it will need a fraction more HP, so in came the Yasuni exhaust....

[i did several ninja-edits after reading this brain fart ]