AMERICANS: Would you buy a 125cc motorcycle for the street?

[ProDigit]

Originally Posted by woodsrat

I know I can be pretty obsessive about motorcycle weight (irritatingly so among my friends who ride "big bikes" who can't understand why I like flyweight bikes so much and won't ride bikes like they have anymore) but a vehicle's weight vs. it's power output is a very important factor in how well they perform, whether in outright performance or fuel efficiency.

I found a blog that uses basic math to show how much weight has on a vehicle's performance and wanted to share this with you:

How to Compare Weight Savings to Horsepower Gains | Tuner University

Like I said for me it's not so much about riding a 125 as it is enjoying a bike that you can throw around like a bicycle. If I could ride a 250 that weighed about the same as a currently available 125 like my K-Pipe (around 250# out the door) I'd be on it.

Problem with 250cc's is the power output.
It'll go faster, thus it'll need better brakes to stop from higher speeds.
Better brakes means the frame needs to be sturdier.
A grom does fine at 60MPH, but I had a similar scooter, that I took to 80MPH (downhill and tailgating), and the whole frame became wobbly and unstable!

If you're interested, there are people that have successfully modified the Grom 150cc engine with a Turbo (probably an ihi rhb31 turbo, since that's the smallest commercially turbo available), and a fuel commander; which is about as fast as the tuned 180cc BBK that's for sale for it. (Round about 100MPH)

[jcp123]

Maybe a 125 two-stroke? I had fantasies about buying just such a KTM many moons ago when I moved to Texas.

I've never ridden anything under 600cc (Honda Shadow) on the street. I definitely would feel comfortable going smaller, but I have little enough experience that I'm not sure how a 4-stroke 125 would feel.

[woodsrat]

Riding my stock Lifan 125 powered step throughs and K-Pipe is a hoot. Around town they have plenty of power and on the 40-50 MPH streets they have plenty enough speed to keep from being run over. The Passport with the 141cc kit and cam is even more fun and regularly impresses people with how fast it is light to light.

Occasionally I'll hit the in-town interstate (50-55 MPH) for short distances if I'm in a hurry and while I'm the slowest vehicle out there so far I've not been run over. Yet.

There are lots of guys on the hondagrom.net website who regularly get on the autobahn with their bikes. They're very brave.

Me? I prefer to travel on the backroads and old highways. I feel perfectly safe traveling the roads that were left behind when the interstates came along and obsoleted them.

For those with interstate addictions small bores ain't the ticket. For everybody else they're a hoot and a nice alternative to riding a heavy bike. I haven't straddled a big 'un in years and don't miss 'em at all.

[ctmaybury@yahoo.com]

When I was between 15 and 20, it was all about performance, racing friends in the mountains. I learned a technique called counter steering to easily throw a 500 lb bike around from corner to corner. Riding a bike stopped being about racing long ago. The bigger the better mentality hasn't changed yet though. Bikes on my wish list include a 1800 cc goldwing and a giant harley with full fairing trunk and bags. Like all motorcycle enthusiasts, I'd like to have about 10 bikes ranging from small to big, dirt to street. Years ago I rode a honda v twin 1800 cc that was a lot of fun too. Is there a place for these bikes on ecomodder? Not really. I'm trying to be the other side of the coin here, and say that the fun is still there with big bikes.

[ProDigit]

If you get a high-rev engine, often times 600CC is all you need.
Plenty of acceleration in the higher RPM range, lower gears, yet not too much HP lost on top.

With anything bigger than 600CC, the bike will be most fun to ride at 100+MPH, which isn't street legal.

On the 1500/1800cc bikes you like, there's plenty of torque (too much actually; you can make the wheels spin), the weight is too heavy (about 1/2 heavier than a 600cc sports bike), too low MPG (averages between 30-50MPG, vs 50-66MPG for a 600cc), and peak HP is limited (because most of those big bikes only do 120MPH tops).

I don't think anything beyond 100MPH is any fun to ride.
So for me, the optimal bike would be anywhere between 400-600cc.
A 600cc sports bike, is hard to keep the front wheel down on a 0-60MPH run.

[ctmaybury@yahoo.com]

If I was still interested in that kind of riding, I'd probably be on a gsxr 1100. I don't know how fast it goes, but guess would be 180 mph. I've been to 150 on a 1000 interceptor. Top speed is more a function of aerodynamics than displacement anyway. Adrenaline junky days are long gone. Fun and top speed are 2 very different things. The performance you get out of a 600 these days is amazing, but I do prefer the gearing and torque on a litre bike. You get nice low rpm on the freeway and you don't have to rattle the gearbox so much. The fastest bikes in the world used to be the 500cc 2 stoke formula 1 bikes. I think those were replaced by superbike 4 strokes, but don't follow racing anymore. These days, my idea of a great ride is the wife on the back, a great mountain road, all the gear with (winter and summer jackets chaps and rain gear just in case). In Colorado the weather can change fast. I like the trunk / backrest so she's comfortable. All this stuff makes the bike in the 700 lbs range. Better have a liter minimum.

[jcp123]

I think talking strictly displacement is a bit misleading.

I had a 1200 Sportster. It had a specific output about where a Chevy LS/1 was, less horsepower than a 600cc sport bike, but with a flat powerband. At 545lb wet with a low center of gravity, it felt good.

[ProDigit]

Originally Posted by ctmaybury@yahoo.com

If I was still interested in that kind of riding, I'd probably be on a gsxr 1100. I don't know how fast it goes, but guess would be 180 mph. I've been to 150 on a 1000 interceptor. Top speed is more a function of aerodynamics than displacement anyway. Adrenaline junky days are long gone. Fun and top speed are 2 very different things. The performance you get out of a 600 these days is amazing, but I do prefer the gearing and torque on a litre bike. You get nice low rpm on the freeway and you don't have to rattle the gearbox so much. The fastest bikes in the world used to be the 500cc 2 stoke formula 1 bikes. I think those were replaced by superbike 4 strokes, but don't follow racing anymore. These days, my idea of a great ride is the wife on the back, a great mountain road, all the gear with (winter and summer jackets chaps and rain gear just in case). In Colorado the weather can change fast. I like the trunk / backrest so she's comfortable. All this stuff makes the bike in the 700 lbs range. Better have a liter minimum.

The first thing I do, when I buy a bike, is gear it as high as I can.
Change the front sprocket, to +1 tooth (or +2 if possible), and the rear anywhere from -3 to -10 tooth.
That way, the final gear is pretty tall.
All the gears are taller, but I can still shift without using the clutch (they're close by one another, but the overall gear ratio increases a lot with the sprockets)..
It's hard to explain, but it acts more like a wide space gearing (like on a 4-5spd roadbike), while it still is geared narrow enough to shift without using the clutch.

Most of the time, the bike revs at around 2k RPM at 45MPH, which is about the same as my car.

A lot of my street bikes reach between 60-80MPG.
If I'm not holding down the front, my FZ-07 does a wheelie in 1st or 2nd gear. 3rd gear is more forgiving, but if I lean back too much, it'll do a wheelie there as well.

[Daschicken]

Originally Posted by ProDigit

Most of the time, the bike revs at around 2k RPM at 45MPH, which is about the same as my car.

Jealous! My CBR 250R is running 5640 RPM at 45, the little viffer is doing 3959. The VFR 800 would be doing 3099, below 3K in top gear it would develop a sort of chain rattle that moved throughout the whole bike and felt as if the engine was lugging. The VF 500 I rode before the 800 had a chain that was looser, yet would never make that rattle, it was also a 360 degree crank if that matters. I can go full throttle in 6th gear at 2K RPM in my 17K RPM capable CBR 250 and it doesn't complain at all. Don't remember how the VFR 400 reacts to that kind of sitcheation', haven't ridden it enough, or recently enough.

Originally Posted by ProDigit

A lot of my street bikes reach between 60-80MPG.

More jealous! Carburetors and low coolant temperatures, along with having to keep up with my dad prevent me from seeing numbers like that. I need to start blocking off the radiators on the bikes.

Originally Posted by ProDigit

If I'm not holding down the front, my FZ-07 does a wheelie in 1st or 2nd gear. 3rd gear is more forgiving, but if I lean back too much, it'll do a wheelie there as well.

The VFR 800 I used to ride would do power wheelies in first, which tops out around 60-65 mph, but wouldn't do them anywhere else. If it was wet out it would do a rolling burnout. Neither the CBR or the little VFR will even tempt a power wheelie, the throttle response on them is way too slow even if the power was enough. Carburetors! Yay!

[ctmaybury@yahoo.com]

My last 2 bikes had shaft drive (v65 magna and suzuki madura). I liked skipping the chain maintenance. Do any of the small bore bikes come with a shaft drive? It used to be chain=performance bike and shaft=old mans bike. Or in the case of a sportster 1200 like jcp123 mentioned belt drive=performance. Sportsters are very high on the fun factor. That flat power band is great. Does anyone remember the 2 strokes of the 70s? Rd400 yamaha or suzuki gt series. No power at all until you hit that power band then you couldn't keep the front wheel down.