Please Help!!! Upgrades Upgrades Upgrades!!!!!

[psprat496]

Ok, I have a Schwinn Riverside with a 66cc skyhawk engine mounted on it. Everything is stock and I love it but I want to go FAST!! I top out at 32mph right now (courtesy of the speed trap down my street) and I want to be able to maintain that speed for a long time and for it to not be my top speed. Basically what I'm looking for are upgrades. My original plan was this:
1x Black Expansion chamber exhaust (sickbikeparts.com)
1x 36tooth Sprocket (spookytoothcycles.com)
1x CNS Carbeurator (spookytoothcycles.com)

From what I understand, the exhaust is going to help the engine cycle the air out allowing the air filter on the carbeurator to suck in more air. The carbeurator will also be gulping down more fuel than stock allowing me to travel without that bogging sound I hate. And the sprocket is just going to add another 8mph automatically because it's just gearing.

Now what I need are your opinions. Any flaws in my plan? Anything I shouldn't buy? Anything I should maybe look at? I am really not too good at understanding these bikes but I thought this would be a great place to get everyones opinions. Hope you guys could help me out. Thanks!!

 

[bairdco]

from what i've heard, those cns carbs ain't all they're cracked up to be. by that, i hear they crack at the mounting flange, are hard to tune, and that they suck, and not air, like they're supposed to. I run the stock (at least with my 66 starfire) NT carb and i think it's a great carb, after i polished it all out inside.

the "8mph" with the sprocket is approximate. depends on weight, rolling resistance, etc, but gearing is the main way to get any top speed outta these bikes, it's just how long it takes your bike to get there. you'll sacrifice low end and off the line start-ability.

but who cares, right? (i run a 32t on my 26" and a 30t on my 24")

expansion chamber's a good way to go for bolt on performance.

while you're waiting for all these expensive parts, you can port-match your intake manifold, dial in your mixture, plug, needle setting, and everything else you can think of, so you're getting the most outta your engine before you start bolting other stuff on.

 

[oylavabeer]

Port and polish

 

[Hot Wheels]

Shift Kit.

 

[bairdco]

real motorcycle.

just kidding.

i just think it's better to do what you can with the stock engine before you start throwing money at it. (sorry sponsors and vendors)

i mean, expansion chambers and new carbs and all that are great, but it's fun to see how much you can get out of your motor with nothing spent but time. even if you know very little about the inner workings of them, it's easy enough, and there's enough threads around that'll walk you through anything.

like my bike (http://motorbicycling.com/f38/backwards-engine-experiment-1939-colson-13458.html,) carb, exhaust, and engine are just modified from stock. the only cost was gasket material and dremel bits, and time.

i'll put this bike up against anyone in a race. it screams.

imagine what it'd do with a dellorto carb and a tuned exhaust...


(edit) by all means, support our sponsors, they're the future of our "hobby," i'm just sayin' to get the most out of your bike, learn to tune it, first...)

 

[MikeJ]

Get a real motorcycle if you need speed.

By law, these motorized bicycles are limited to speeds around 30 mph, depending on the state. If you intentionally exceed engine output power and speed limits imposed by state lawmakers, you should look forward to going to court and paying fines. This is only the beginning. If you have an accident, don't expect anyone like insurance companies to come to your aid.

Learn your state's laws. Ride with discipline and responsibly. And ride often!

MikeJ

 

[Venice Motor Bikes]

Doood... Seriously, go with the expansion chamber & a 40T sprocket & adapter from Jim!! (Keep the stock carb!)

Oh, & get good brakes!!!

 

[BarelyAWake]

It's interesting how infatuated we all are with top speed, doing whatever we can to gain that elusive coupla extra miles an hour lol - while I can sympathize, heck - I've more than once found myself hunched o'er the bars with the throttle cranked, trying to "will" that last 1/10mph to flicker on my GPS...

Yet I gotta say it's only part of the equation. While top speed is ofc related - acceleration is my "holy grail" and fortunately it's where ya see the most improvement for your efforts... provided ya don't mess up the gearing too much in a sacrificial attempt for top speed.

While top speed is great fer braggin' rights - acceleration is a heck of a lot more useful whilst playin' in traffic, or even racing another MB heh

Still, it's pretty much the same game as far as mods go - expansion chamber, light port & polish, a real carb ifn ya can, shift kit and as much weight & drag reduction as feasible - it's amazing how much even a dry chain will slow ya down

I will say the phrase "geta motorcycle" makes my ban button itch o.o

 

[Pablo]

Think 40 mph face plant. Bike helmet? Hmm.....40 mph with a sprocket bolted to your spokes. I trust in very little these days.

Don't need another dead motorized biker. Every incident screams "Ban them things off the roads!!" Who here doesn't think there isn't some do gooder politician just itching to make more and more MB laws? Or just outright and complete ban. And they would have big industry on their side.

Top speed? Yeah it's alluring. But many, many potential customers first questions are: "How fast will it go?" and/or "What is top speed?" And yes I too have topped out a bike or two on the street. 41 mph. I felt REALLY stupid afterward.

So, BarelyAWake nailed it home on what you should be after. Torque. The others gave you EXCELLENT advice on some beginning steps.

1) Carb - I've tried a few. I run a stock carb. These un (reed) valved engines are just not able to take "advantage" of sophisticated carburation. Use stock, but jet it properly. Use a good air cleaner.

2) Exhaust - no doubt in my mind you are correct there. An expansion chamber is the single best bolt on item for a 2-stroke engine. I've drilled, cut, hacked the stock exhaust and sorry there is no gain there, but every time I bolt on a chamber, whammo bottom line grunt, mid rpm power and top end freedom.

3) Buy a Dremel. As the others have mentioned this is about the cheapest, best thing you can do. See how terrible the intake manifold matches the intake port. Open up the manifold at the flange, cut out the restriction at the bend. (BTW the mini sanding drums work the best). Of course make sure the gasket matches. Ditto on the exhaust side, even with the expansion chamber, get port, gasket and little mini-manifold all matching. A little humor is the stock exhaust gasket with it's dime sized hole bolted to your nicely port matched manifold!

4) Compression ratio. Increase it. Raising compression ratio increases torque. It's that simple. Get a slant head or better, mill your stock head, use a good new gasket. Use the Al paint trick if worried about leaks. Use good head studs.

5) Spark. Good plug. I have a hard time beating NGK. I like the extended tip BP6HS. I don't run plugs really long, but these rarely foul. I just consider plugs as consumables, fairly inexpensive. And get a good wire and boot, plus use silicone grease on both sides.

6) Fuel/oil. Midgrade IF you increase your compression, regular if not (you will see NO gains and maybe losses with premium on a stock engine). Pick a good oil and run it fairly oil rich. I don't like Amsoil 100:1 and I don't like Opti 2 100:1 in these engines. Neither gives top ring seal and top performance and may add to bottom end wear. After break-in, a couple tanks at 20 or 25:1, running at 25:1 or 32:1 with a good synthetic oil is ideal. For better performance. I use castor oil for one on the fluid ounces to make a gallon.

7) Use your gears!

Do the above (all) seven properly and you will love your bike more, respect the deadly top speed, and actually find the 0-30 to be the most fun you can have while fully clothed.

 

[Whizzerd]

This might be kind of a Mr. Obvious thing but keeping your tire pressure at max recommended helps with acceleration, top speed and fuel economy. And of course a Tuned Pipe exhaust system. I've always been amazed at how they work.

 

[psprat496]

Thanks everyone for all the replies! So what I'm going to go now is throw that CNS Carb out of the equation and replace it with one of those High Performance Air filters from Sick Bike Parts. Now about tuning the stock carb. I've heard in almost every thread people telling each other to "port" and "jet" their carbs and I kind of feel stupid asking since you guys use it so much around here, but what is the process of "porting?" And like I said I'm not really familiar with these parts and the tools I'm able acquire are limited.

 

[Venice Motor Bikes]

Don't forget better brakes!!!

 

[psprat496]

Don't forget better brakes!!!

Yeah I'm going to swap out my brake pads for new ones. I got a dual pull lever too so that really helps. Also, has anyone ever tried put like a front disk brake on their bikes?

 

[Cannonfish]

I installed a front disc on mine, there's not much to it at all. Avid makes an all-mechanical disc brake they call the "BB5" - they don't require you to mess with brake fluid, they're relatively cheap (about $30 for the caliper and rotor, and you can use your old hand-lever), and they have excellent stopping power.

If your current fork doesn't have drop-outs for a disc caliper, you can find a replacement fork with drop-outs online for pretty cheap. Or ask the mechanics at your local bike shop if they know anyone who could weld drop-outs onto your existing fork (not difficult, but it will damage your paint job). The disc brake adapters out there that bolt onto your axle are scary; I wouldn't use them on the front wheel.

 

[Venice Motor Bikes]

has anyone ever tried put like a front disk brake on their bikes?

You haven't looked at the pics on this site much, have you?

 

[psprat496]

I installed a front disc on mine, there's not much to it at all. Avid makes an all-mechanical disc brake they call the "BB5" - they don't require you to mess with brake fluid, they're relatively cheap (about $30 for the caliper and rotor, and you can use your old hand-lever), and they have excellent stopping power.

If your current fork doesn't have drop-outs for a disc caliper, you can find a replacement fork with drop-outs online for pretty cheap. Or ask the mechanics at your local bike shop if they know anyone who could weld drop-outs onto your existing fork (not difficult, but it will damage your paint job). The disc brake adapters out there that bolt onto your axle are scary; I wouldn't use them on the front wheel.

Well this is a Schwinn Riverside Beach Cruiser I have so would the disk brake fit on my front wheel?

 

[psprat496]

Think 40 mph face plant. Bike helmet? Hmm.....40 mph with a sprocket bolted to your spokes. I trust in very little these days.

Don't need another dead motorized biker. Every incident screams "Ban them things off the roads!!" Who here doesn't think there isn't some do gooder politician just itching to make more and more MB laws? Or just outright and complete ban. And they would have big industry on their side.

Top speed? Yeah it's alluring. But many, many potential customers first questions are: "How fast will it go?" and/or "What is top speed?" And yes I too have topped out a bike or two on the street. 41 mph. I felt REALLY stupid afterward.

So, BarelyAWake nailed it home on what you should be after. Torque. The others gave you EXCELLENT advice on some beginning steps.

1) Carb - I've tried a few. I run a stock carb. These un (reed) valved engines are just not able to take "advantage" of sophisticated carburation. Use stock, but jet it properly. Use a good air cleaner.

2) Exhaust - no doubt in my mind you are correct there. An expansion chamber is the single best bolt on item for a 2-stroke engine. I've drilled, cut, hacked the stock exhaust and sorry there is no gain there, but every time I bolt on a chamber, whammo bottom line grunt, mid rpm power and top end freedom.

3) Buy a Dremel. As the others have mentioned this is about the cheapest, best thing you can do. See how terrible the intake manifold matches the intake port. Open up the manifold at the flange, cut out the restriction at the bend. (BTW the mini sanding drums work the best). Of course make sure the gasket matches. Ditto on the exhaust side, even with the expansion chamber, get port, gasket and little mini-manifold all matching. A little humor is the stock exhaust gasket with it's dime sized hole bolted to your nicely port matched manifold!

4) Compression ratio. Increase it. Raising compression ratio increases torque. It's that simple. Get a slant head or better, mill your stock head, use a good new gasket. Use the Al paint trick if worried about leaks. Use good head studs.

5) Spark. Good plug. I have a hard time beating NGK. I like the extended tip BP6HS. I don't run plugs really long, but these rarely foul. I just consider plugs as consumables, fairly inexpensive. And get a good wire and boot, plus use silicone grease on both sides.

6) Fuel/oil. Midgrade IF you increase your compression, regular if not (you will see NO gains and maybe losses with premium on a stock engine). Pick a good oil and run it fairly oil rich. I don't like Amsoil 100:1 and I don't like Opti 2 100:1 in these engines. Neither gives top ring seal and top performance and may add to bottom end wear. After break-in, a couple tanks at 20 or 25:1, running at 25:1 or 32:1 with a good synthetic oil is ideal. For better performance. I use castor oil for one on the fluid ounces to make a gallon.

7) Use your gears!

Do the above (all) seven properly and you will love your bike more, respect the deadly top speed, and actually find the 0-30 to be the most fun you can have while fully clothed.

Now what exactly is porting or jetting? How do I do it? Can I buy a carb from someone who has already done this?

 

[Bikeguy Joe]

Ultimately, if you want to go real fast have someone put you and your bike in the back of a pick up truck and run down the free way,

 

[oylavabeer]

Porting is maximising air flow through your motor. Jeting is drilling out the fuel jet in your carb to let more (or less iff you solder it ) fuel through the carb

 

[Creative Engineering]

Now what exactly is porting or jetting? How do I do it? Can I buy a carb from someone who has already done this?

Kid...just enjoy the ride, and be glad you haven't fallen face first into the pavement!

90% of the bicycles available are not intended, (or manufactured), for high speed. If Ya wanna go fast...start with a high dollar...go fast bike. It will be expensive...very expensive.

Jim