I just ordered a Koso racing clutch setup from eBay, so we'll be seeing a review of it here soon!

I get asked incredibly often how to choose variator weights. This is a tricky question, because the weights you choose depend a lot on where your bike is in its path to Voodoodom. Nearly any bike will get improvements by going to sliders from rollers.
A stock bike might work well with 11g sliders, while a heavily modified bike may have anywhere from 8g sliders to 14g sliders, and everything in between.

I'll show you here an easy way to choose the weights that will be best for your bike.

Assuming that you want a good balance between acceleration and top speed, you want a weight that will get the variator belt all the way to the top of the ramp as quickly as possible. Lighter wieghts will give you more off the line acceleration, but will not let the belt reach the top of the variator ramp, so you loose out at the top. Heavy weights will give you a bit more rotational mass at the variator which lets you squeeze some extra speed out of the top end, but you loose out at the line.

To get the best balance, first take apart your variator. Then take a dark colored marker and fill in the top inch to inch and a half in a square. Then re-assemble the bike and go for a ride. Choose a spot where you can try to make a run for your top speed on flat ground.

Then go home and take apart the variator again. You'll notice that the belt has rubbed off the marks you made as high up as the belt traveled. With any luck, you'll be just a few milimeters from the top. If thats the case, your weights are perfect. If you've still got a long way to go, then get heavier weights. Too sluggish off the line? You probably went too heavy.

On a near stock bike you'll want to start around 11g. For a modified bike with a heavy (1500RPM or above) contra spring, 12g or 13g is a good starting point.

MOD COST: Free!

MOD DIFFICULTY: Very easy, if you can change your oil, you can do this.

SPECIAL TOOLS: A Drill, a 3/4 inch bit.

BENCHMARK: Will increase both torque and HP output. Total increase depends on how much airflow you get, as well as altitude that you ride at.

Many people get discouraged by mods that cost a lot of money, and begin to believe that the only way to speed is through botomless pockets.

I'm going to do a series of mods that are cheap to free, and while they may not net you the gains that a bigbore kit will, they're noticeable and inexpensive.

The first mod and one that often overlooked is the airbox. All internal combustion engines from 50cc to 500ci are basically big air pumps. The more air and fuel you can get through them, the more power you'll make. So this mod is focused on the intake side of the engine.

The airbox is the small black plastic thing on the left side of the bike directly above the CVT(Transmission).

The first thing you'll want to do is pull the screws off and take a look inside, you'll see the airfilter, the cover, a intake tube connected to the cover, and on the back of the air filter a tube that runs to the carburetor.

You'll also notice there is a divider in the cover. This divider is a restrictor. It limits the total airflow ability of the air filter. The first thing you're going to want to do is remove that. Removing this part alone DRASTICALLY increases your airflow. The other part to notice is the tiny drain hole in the bottom of the cover that leads to the external drain pipe.
You can take a 3/4 inch drill bit and drill this out to provide a bit more airflow.

The last thing you'll want to do is remove the upper intake pipe into the airbox. This pipe will slow the velocity of the air down and result in less air into the carburetor.

Now that you've increased your airflow, you're getting into a part of the motor that requires a lot of tinkering. Your carburetor.
Its not worth much to increase your airflow if you're not also increasing your gas input. Infact, if you DON'T jet up at this point you're likely going to be running lean, and that can cause you serious engine issues.

Jetting up is very easy to do, but quite hard to do right. I could write at length here about getting your carburetor dialed in just right, but the fine folks over at Battlescooter have written this awesome CVK carb writeup Its geared towards the carburetor in a Honda Ruckus, but its exactly the same for the Buddy.

Apparently I was mistaken when I thought they'd said they WOULDN'T replace my pipe again, they actually meant they wouldn't want to keep giving me pipes likely to fail, and outlined several other options.

First some back story: Apparently there have been a VERY high failure rate of the Prima exhausts for the Vespa GT's. All of them are failing with a broken upper weld just like mine. Scooterworks returned/is returning all the pipes to the company who makes them(Apparently not NCY, but I missed who they actually said it was) with orders to revise the design across the board. It was mentioned also that a lawsuit might be pending over this...

So they said if it failed again, there'd be other options. A: They'd refund the money and I could find an alternative. B: I could wait till they revise the pipe design and I could get a new one hot off the presses. Or C: I could see if the carbon fiber generic GY6 pipe would fit, and they could exchange for that one.

So it looks to be a much happier ending that I'd feared.

I'm a big fan of Prima products, don't get me wrong. Many of them are made by NCY in Taiwan and are fantastic products.

From a performance standpoint, they add a LOT to your bike(I'll review them too!)
But it seems they have a serious flaw in their latest batch of performance exhausts. The upper weld just doesn't seem to be able to hold on. I've had it fail on TWO pipes now. The first one failed so bad that it caused other welds to break, and the cannister had separated from the header. The second weld isn't as bad of a break, but will likely get worse if not repaired or replaced soon.

I love Scooterworks, and their Prima line of parts, but it might be time to find another source of performance pipes for the Buddy, unless Prima can get their pipe problem cleared up.

MOD COST: $29.99 from Scooterworks

MOD DIFFICULTY:Most of you will have a shop do this.

SPECIAL TOOLS: A shop.

Most of you know that I put a lot of miles on my Buddy. Far more than nearly anyone else(Except Bonegirl!). That means that I get to try more tires than most people.

The last set I tried were Pirelli Diablo's, which I chose for their higher than average speed rating, and their reputation for good grip. And though I liked them, Pirelli has stopped making this tire in 10 inch. That means it was again time for me to go tire shopping and find a new brand.

Modernbuddy folks were talking about the fact that Scooterworks had begun carrying a new brand of tire out of China known as Vee Rubber. Nobody however seemed to have actually tried a set at that time.

There were several things that caught my eye about these tires, the largest being that they came in L(75mph) and P(92mph) ratings, a must for the speeds my Buddy can do, and far higher than many other brand's J(62mph) rating. The second reason for choosing this tire was it's relatively inexpensive price at $29.99 a tire, a fair bit lower than the $54.99 cost of the widely popular Contenental Zippy2's that many people use on their scooters(Also a J rated tire).

After getting them on my bike, I imediately noticed that the tires were extremely grippy.
They seemed to bite down with a ferocity that easily match the Pirelli's I had on there previously, and was far more at one with the road than the Zippy2's or ChenShin stock tires. As I rode them to work the next day, I was even more impressed. There is a good long twisty road on my way back from the office, and I took advantage of my new found magnetic attraction to the road to enjoy it.

I MAY have enjoyed it a bit too much....

I think Vee Rubber may have negotiated a deal with Mother Nature to get a pass on the laws of gravity.

Only time will tell if these tires will last through the miles that I put on them, and I will likely update this article after they have a few more miles, but for the 55 miles I put on them today and yesterday, I'm very pleased with the results.

MOD COST: $10-15

MOD DIFFICULTY: Moderate. Requires the disassembly of the clutch.

SPECIAL TOOLS: Impact wrench required.

MOD BENCHMARK: Big increase in initial acceleration, no change in top end.

NEXT STEP: Contra springs.

Clutch springs can be one of the most confusing upgrades you can do to your bike, but also one of the most rewarding mods to your off the line acceleration.

The biggest confusion is in how they are rated. You can get clutch springs in 1000rpm, 1500rpm, and 2000rpm sizes. Most people assume that this rating system is the RPM that the springs engage the clutch. This is incorrect. Its actually the INCREASE in RPM over the stock springs that the clutch engages. So that would technically make your stock springs a 0RPM spring.

All aftermarket springs are also rated by color, the 1000RPM is blue, 1500RPM is yellow, and  2000RPM is red.

The clutch springs control how much RPM is allowed before  the clutch engages completely.
This affects how hard your bike leaves the line, as well as how hard your clutch stays engaged while in motion.

The 1000RPM spring is mostly for those who want a slight bit of improvement in off the line jump, but want to ensure that they don't loose out in the top end at all. These would be good springs if your final goal is to have a bike with a very high top end, and you're not really worried about initial acceleration.

The 1500RPM Spring offers a great off the line jump without costing you much in the top end, and is the spring I use personally in my Buddy.

The 2000RPM spring will give you a HUGE jump off the line, but in testing has been found to not have enough strength to keep the clutch engaged at high speeds, and your top end will suffer badly.

This mod is much like installing sliding variator weights in that the more mods you do down the road, the more this mod helps.

MOD COST: $$199.99 from Scooterworks

MOD DIFFICULTY: Dificult. You should either be a mechanic or have your mechanic do this.

SPECIAL TOOLS: Regular socket set and some screwdrivers.

MOD BENCHMARK: HUGE increase across the board. Pulls HARD!

NEXT STEP: Replace the head.

The first thing I'll note is that after opening the box to inspect and verify all the parts that while there is a sheet with some tips you need to know about the kit, there are no installation instructions of any sort. This is not the sort of upgrade that you should try if you don't ALREADY know how to pull apart a motor.

The first thing I did was remove the petcarrier/seat assembly as well as the front panel (the one with the cooling vent behind where your feet sit)
to reveal the motor.

Next I removed the fan and flywheel cover to reveal the timing marks. This is important so you can get the motor timed properly for reassembly.
Note that when the "T" mark is aligned with the indicator arm, the crankshaft is at top dead center(TDC)

I then removed the vent return hose from the valve cover and the valve cover itself via the 4 bolts at the corners revealing the camshaft and rocker assembly.

The rockers are held in by 4 nuts with lock washers. These nuts are attached directly to the engine studs that hold the whole engine together.

After you remove those nuts the rockers should come off with some gentle pulling. Note the side labeled E X as this is the exhaust valve rocker and must end up on the same side of the head when re-installed.

After you remove the rockers, the camshaft will be mostly free of the head, though still held in place by the timing chain. Note that there is a line etched across the sproket on the end of the cam. When this line is parallel to the head and the hole in the sprocket is up, the cam is at top dead center(TDC). Gently pull up on the back of the camshaft to tilt it out of the timing chain and remove the cam.

Next I unbolted the two bolts holding the intake to the head and separated the intake from the head. Note that there is a tiny rubber O-ring on the end of the intake. Don't loose it!

Then I unbolted the two bolts that hold the exhaust to the head, and the two rear mounting bolts and removed the exhaust pipe from the bike.

Next you need to remove the plastic cover from the engine. It has two screws, one on each side of the motor, several tabs, and a bolt on the left side of the motor. Pull the top cover up and out(its a tight fit). You can leave the lower cover in place.

Now you can see the chain tensioner sticking out from the side of the cylinder. It looks like a tube sticking out of the top side of the cylinder with a bolt in the end and two bolts near the base. Remove the two bolts and the tensioner will come out of the cylinder.

After that I removed the two long gold bolts from the head that are on the left side of the engine. These bolts hold the head to the block directly.

The head should now be loose on the block, but you'll notice that the intake studs are too tall to clear the bike. There's a simple fix for this.
Unbolt the lower rear shock bolt and pull the shock out of the way of the motor. Now you can pull up on the rear tire to tilt the front of the motor forward so those bolts clear. This can be done by yourself, but would likely be easier with 2 people.

Remove the head now, being sure to pull it straight so as not to put any strain on the engine studs.

Now you should be able to remove the lower chain guide. It just pulls out now. The upper chain guide can stay in place.

At this point the cylinder should be free of the block, and you can pull it out and remove it. Again, be careful of the studs.

Now the piston should be free and open on the end of the rod. There are two C-Clips on the ends of the wrist pin on each side of the piston. Use a small flat blade screwdriver(Or a C-clip tool if you have one) and remove them, then push the wrist pin out of the piston with your finger. Now the piston will come off the end of the rod.

At this point its basically the whole process in reverse with one notable exception. The new cylinder comes with a different style chain tensioner that will not fit under the engine cover. You have to cut a chunk out of the cover to clear the new tensioner. DON'T opt to leave the cover off. Its needed for cooling.

If you've actually READ this far I'll just preface this again. You're replacing 1/2 of your motor to do this upgrade. If you've never done this before you probably shouldn't try now! THIS IS NOT A MOD FOR BEGINNERS!

MOD COST: $90 from www.buggypartsnw.com

MOD DIFFICULTY: Easy. If you can change your oil, you can probably change your variator.

SPECIAL TOOLS: Impact wrench is required to remove the variator nut.

MOD BENCHMARK: Noticeable increase in initial acceleration, as well as higher top end.

NEXT STEP: Clutch springs would be a good next step.

The upgrade of the variator is probably one of the biggest bangs for your buck that you can do early on in your upgrades.

The Dr Pulley variator offers both a steeper ramp path as well as a longer total ramp length than the stock variator. So you might ask what this means to you? I'll explain.
as you engage the throttle the variator plate is pushed apart by the sliders causing the pulley faces to move towards each other. This pushes the belt outwards and makes the pulley larger.

Your initial acceleration is affected by how quickly the pulley can move the belt to the top of the ramp. Since the ramp is steeper on the Dr Pulley variator than on the stock variator, you reach the top of the ramp sooner, resulting in faster initial acceleration.

The ramps on the Dr Pulley variator are also longer than the stock variator. This means that the belt can be pushed farther up than on the stock belt, resulting in a higher "final gear ratio" than the stock variator can achieve. Because of this the variator can provide a slightly higher top speed than the stock variator.

This is one of the few modifications that will give you a boost in both initial acceleration as well as total top speed, making this upgrade a fantastic bang for your buck. It also is a very durable well built part, so you won't be replacing it later time to keep up with your mods.

Another bonus of this part is that the manufacturer coats the ramps in a friction reducing compound, so these variators are easiler on your sliders/rollers than a stock ramp resulting in longer lasting weights.

MOD COST: $25 shipped from eBay seller Autotech355 or www.buggypartsnw.com

MOD DIFFICULTY: Easy. If you can change your oil, you can probably change sliders.

SPECIAL TOOLS: Impact wrench is required to remove the variator nut.

MOD BENCHMARK: Not a huge gain in performance, but a good starting point for new modders.

NEXT STEP: A variator upgrade would be a good next step.

One of the very first modifications I did to my bike when it was totally stock was to swap
out the sliders for something more performance oriented.

After reading around on Modern Buddy I settled on Dr Pulley as the brand I wanted. They offer a uniquely designed sliding weight quite unlike the stock rolling weights. These sliders move more smoothly across the ramps and allow for a more even power band due to the unique sliding design. They also allow for the variator to move farther open since they are slightly taller than the stock rollers. (See photos for example)

Dr Pulley also claims they last 20% longer, a claim that holds up in my testing.

I also wanted to change weight of the sliders, as I thought that the Buddy wasn't quite in its optimal power band, and that a slightly higher RPM would serve my needs more fully.
The stock weights are 11.5g, and the ones I was installing were 11g. Not a huge difference, but I wasn't going for a huge change in RPM. The Buddy runs NEARLY where it needs to be already if you are looking for a good balance of top speed and initial acceleration.