135 mph 350x???

[HuffieVA]

there is a huge difference between 107 and 135, and at 4000 rpm, with 25" tires you would have to be running almost 1:1 / direct drive to get 100mph... I'm just saying I can see 100+ maybe even 125/130 with an RD350 twin smoker, but I just cant envision a mid 80's single cylinder 350cc thumper trike breaking 100mph, at least not without tearing itself to shreds in the process

[jensenracing77]

6th gear on a 350X is overdrive

[HuffieVA]

Yes you are correct:

Transmission 1st gear ratio: 2.750: 1
Transmission 2nd gear ratio: 2.050: 1
Transmission 3rd gear ratio: 1.609: 1
Transmission 4th gear ratio: 1.308: 1
Transmission 5th gear ratio: 1.103: 1
Transmission 6th gear ratio: 0.935: 1

But the Primary Ratio is 2.833: 1

So even though 6'th gear is less than 1:1 the primary ratio changes the actual ratio... and you are nowhere near a true direct drive...
if you were and you made it to 8000rpm you would be topping out at slightly over 200mph, at 200mph I would strongly suggest a full fairing and a visor-less helmet

[jensenracing77]

i wasn't thinking about the primary reduction. all i know is with what i had i made it to 107MPH and ran out of power not RPM.

[WilliamJ]

don't take this wrong because the ad is full of BS. i just want to say that 135 MPH may not be that hard to reach on an engine like that (if built right). i had a 350X to 107 MPH. the engine was stock bore and stroke but did have a nice cam, piston, valve springs and exhaust. we were trying to see just how fast we could get it to go with the engine built the way it was. i had 25 inch tires on the back, 14T front sprocket, 37T back sprocket. when we were up to speed the back tires were ballooned so tall they were rubbing the back fenders and almost to the heels of my feet so that made them over 25 inches tall total. the poor 350X ran out of power before we ran out of RPM. if i had the power to run it to its full RPM like a (correctly built big CC 350X engine) i think it would have ran at least another 15 to 20 MPH. i never done the math to see what RPM the engine was running but if someone knows how i would like to know. it didn't sound like it was screaming, maybe 4000 area if i was to guess.

The maths of the gearing are that to get to 100mph with those numbers you would need to spin the motor at between 8000 and 9000 rpm. I don't have 350x primary gear reduction details so I have used 86 250r ones. And as someone has pointed out, standard trike tyres are not meant for high speed

However the basic maths of aero drag are that to get from 107mph to 135mph you need roughly double the horsepower (all other things remaining the same). If your original top speed was 80mph then you need about 5 times the horsepower to get to 135mph!!

I don't know the coefficient of drag of a trike with rider but it is not a slippery shape so, being very optimistic, it could be about 0.8 Cd. Combining that with the frontal area - the head-on silhouette area - of say 9 or 10 square feet at best, you will need 60 or so horsepower at the rear wheels to get to 107mph. The additional 28 mph needs another 60 hp because of the drag resistance increasing by the cube.

I think the drag resistance is probably worse than I have assumed because with 0.8Cd and FA of 9 feet you only need 23 hp at the rear wheels to reach 75mph. I read there's about 36 hp at the flywheel of a 350x (it may be more) and 13 hp would be a big loss through the transmission and tyres.
Bill

[jensenracing77]

have you even been over 100MPH on anything? it is not as bad as you think. i had a couple quads over 100MPH several times also. they are not as bad in the wind as you think. at least not that bad on the ground... in the air the wind will blow you all over the place at a much lower speed

[HuffieVA]

have you even been over 100MPH on anything? it is not as bad as you think

Are you seriously asking me if I've ever been over 100?, I suggested a fairing at 200, especially because a 350X (as well as other trikes) has the same inherent aerodynamic qualities of a John Deere B model.... I'm not saying its impossible to get a 350X to do 100, what I am saying is its mathematically/mechanically imposable to do it at 4000 rpm are there quads that do 100? of course but they dont do it at 4grand either...

[jensenracing77]

as i said before, i have no idea how many RPM i was turning. the 4000 was just a guess.

[DRKCYDE]

Maybe its gotta VETC, yo.

[Xpress]

^Or just a VVT-i engine.

[Chazz of Blades]

NAW DAWG! HE DONE PUT ONE O' DEM TRICK PIPES ON DAT THANG! Slick custom exhaust be rockin' the speed.

[Nevkilahonda3]

I'm just throwing this out their maybe hes from europe and maybe he ment KPH k and m are right next to each other now I don't know if a 350x beefed up can do 84mph(135kph = about 83-84 mph) I have never owned one so lets say he clocked it down hill.What do you guys think.

P.S HuffieVA what kind of dodge were you in that did 135 my pos dodge can only hit 95mph maybe more if my ford is pulling it foward !!

[Chazz of Blades]

Check for bent axles and forks.






He might have dropped it down a canyon.

[fabiodriven]

All I know is if Jensen said he did 107, he did 107. Man's a straight shooter.

[HuffieVA]

my main argument was the 4grand not the speed, i think we settled it...