A quick glance at this bike and you might think it's the Kawasaki KLX250, but look closely. It is a little Kawasaki KLX140L that has been modified. The engine got a 160cc big-bore Stage 2 upgrade from American manufacturer Engines Only. The 160cc Stage 2 big-bore kit for the Kawasaki KLX140 includes a high compression piston with rings and clips, head and base gaskets, high performance camshaft and valve spring set.

The performance of the Kawasaki KLX160 is a claimed 16 horsepower out of the modified engine. The modified Kawasaki KLX160 big-bore has a compression ratio of 11.5:1 and runs on regular 91 octane fuel. We used a K&N air-filter and on the Mikuni 28mm carburettor. Kawasaki stock KLX140 comes with a weird shift linkage that doesn't make a lot of sense, so it was scrapped, and an Engine Only shifter took over the gear changing duty.

The combination of 20 more cc and a simple exhaust modification made the little lime-green KLX140/160 monster sound like it was ready to take on the best – and perform like it too. The modified Kawasaki KLX140 lays a beat down on a stock KLX140 in every aspect, from power to handing.

I'm in love. No, make that lust. After a frustrating delay while stock arrived from the USA, Project Kawasaki ZRX1200R is now proudly sporting a pair of K&N air filters purpose-built for the Keihin FCR39 flat-side carburettors. I can now go for a decent ride without fear of sucking rocks, birds and small children through the Keihin FCR's open bell-mouths. It also means I'm likely to in-danger myself if the novelty of snapping open the throttle doesn't subside sometime soon.

The Kawasaki ZRX1200R throttle response with the correctly jetted Keihin FCR39 carburettors is instant, with close to maximum torque on tap from 4,000rpm onwards.

The Kawasaki ZRX1200R power and torque dyno curves are famous for being the most linear in motorcycle history, with a meaty 101.5 to 114.2 Nm delivered over a 4,500rpm range from 4,000 through to 8,000. The power curve is as good as a straight line from 1,500rpm all the way through to 8,000rpm.

I can't resist snapping the throttle open at 4,000rpm and basking in the bark from the four-into-one exhaust and induction rattle from the Keihin FCRs. The sound is simply amazing.

Lots of people are asking themselves how to increase power, for some increasing the bore of the cylinder and cylinder head is the answer. It is true big-bore pistons can produce more horsepower at a very low cost. But sometimes taking doing a bore-up means the thickness of the cylinder walls become unsafe.

What are the alternatives for increasing the combustion volume? The answer is to stroke the engine. Once the piston is in motion, it will do more work if you let it more farther.

Instead of increasing the combustion dome area more and more, stroking an engine allows you to increase the depth of combustion.

Stroking an engine isn't easy. Moving the big-end crank pin off-center by as little as 0.5mm increases stroke 1mm. That means the piston travels up the cylinder an additional 0.5mm and comes down an additional 0.5mm closer to the crank. Obviously, it will hit stuff at both ends unless compromises are made.

If your bikes fuel-tank doesn't leak and you're scratched the paintwork, just carry on riding. If the fuel-tank has more damage, especially on a chromed tank, including dent removal, re-plating and painting, think about serious amounts of money. Fortunately, there are plenty of options in between for refurbishment your fuel-tank.

Simple Dented Fuel-Tank

Simple dents can often be hammered out by a skillful metalworker – if you're lucky, without even cutting a section out of the base. If you try ti yourself, remember that welding or brazing a section back in place can distort the fuel-tank, and welds can leak. Startlingly, even long-unused tanks can ignite momentarily as the petrol varnish inside is reactivated by heat. Part-filling with water during welding is a precaustion, but leave the cap off or the resulting steam can burst the whole thing open.

Complex Crunched Fuel-Tank

Complex crunches are impossible to get perfectly smooth again, though you might be able to get them acceptable. The professional solution is to get the surface as good as possible, then have it copper plated to a depth of upto 2mm. This gives a skilled operator enough leeway to polish out the imperfections without making the fuel-tank itself too thin. From then on it's the usual nickel followed by chrome plating for a perfect finish.

It is no secret, your engine needs an air filter to keep abrasive dust, grit and water out of the combustion chamber. Most motorcycle use a pleated paper filter, and if these are neglected they can get clogged up. This means the engine has to work harder to draw air in.

A dirty filter can also affect the air/fuel mixture on carbureted motorcycle, making the engine run rich, wasting fuel and reducing peak power performance.

A new air-filter costs only a few hundred Baht, but blowing out the dirty one with compressed air is nearly free, and can take much of the dust and crud out. This will allow the engine to breathe easier and get more oxygen flowing, and that means more power!

Most modern cars and many modern motorcycles have immobilizers fitted to them. The reasoning is very simple: if they can't be started they're a less attractive target to thieves. And making your motorcycle less attractive is about the best you can easily do to protect it; you can't stop a determined thief without a very major investment in security.

Of course there's always tracking technology, which may see your motorcycle returned after it's stolen, but what I understand that's expensive and not even sure if this service is available in Thailand. A considerably cheaper alternative that might actually stop a theft is this neat around 1,800 Baht little aftermarket immobilizer.

We found it on the Internet and apparently it is an Australian product, they accept all sorts of credit-cards and Paypal for payment. We fitted one to a friends Honda Wave; despite the low price it looks like a quality piece of kit.

As Mr Errol Corby, of owner of Nicita Corby Australia, explains, the immobilizer offers protection against hoons, joy riders and amateur thieves. It is suitable for use on all motorcycles and scooters fitted with battery power; it doesn't matter whether it is started by electric- or kick-starter.

<img width="205" height="150" class="floatleft" src="https://motorcycleinth.com/images/articles/Engine-Builders-Season-Kicks-in_1.jpg" alt="" />December to mid-March is the busiest time of year for engine builders, in preparation for the forthcoming racing season. Mee has ten engines to do in eight days. It's labor intensive as some4 parts have to be assembled, stripped back down, then measured before being assembled again. Cylinder heads sometimes have to be torqued down onto the cylinder block and then disassembled six to eight times before they are right.

For one engine the cylinder block has been bored and hone4d to 800cc by an external service supplier. The bore diameters are all within three microns of each other, that is a very tight tolerance.

Mee has balanced the pistons and rods on scales, removing parts of the pistons' skirts to achieve perfect balance. The pistons have then been matched to the bores, the largest piston going in the largest hole and so on. Typical clearance between piston and bore is 28 microns all round.

Mee skims the cylinder block on his new-to-him Tecnodue SP330R skimming machine, he's not saying how much though; secrets are engine builders' stock in trade. The company invested in the machine so we doesn't lose time waiting for another company to do the work. Placing the block on the machine's bed, Mee measures that it's sitting squarely by lightly touching the surface to be machined with the cutting tool. Three corners need propping up with a single sheet of paper to make it absolutely right. He's working out exactly what piston-to-cylinder head clearance he wants, so when the conrod stretches at full tilt, the piston will just kiss the head without catastrophically crashing into it.

<img width="220" height="202" class="floatleft" src="https://motorcycleinth.com/images/articles/Changing-the-Handlebar-Height-with-Riser_1.jpg" alt="" />One of the beautiful aspects of a stock or custom motorcycle is the ability to fit the handlebars of your choice for looks and comfort. With that said and the daily increase in handlebar styles coming on the market, you would think there is a set of bars that are perfect for your application, and for 99 percent of riders, there is the perfect set of handlebars. But there are exceptions and a couple of you reading this fit into that short list of exceptions. Let's face the facts: Until you ride your motorcycle with a set of bars, you won't be able to know for sure they are the ones for you.

We found a set of bard that had all the right contours and bends, but the one aspect that needed a slight tweak was the height. This modification is easy to accomplish by using a set of longer mounting bolts and spacers, placing under the handlebar risers. For normal Harley-Davidson risers, a piece of 2.54cm diameter aluminum bar stock accompanied by a set of 12.7mm diameter coarse-thread grade-8 bolts, 2.54cm longer then the spacers is the easy cure for height adjustment. 12.7mm coarse-thread riser bolts have been the norm, but be safe; take an old riser bolt to the store when you shop for new ones to insure you have the correct thread.

Last month we raised the handlebars on our '06 Harley-Davidson Softtail 2.5cm by using spacers made from aluminum bar stock. We cut the bar stock to a rough length and then finished them to final length and drilled a 13mm hole through the length.

If you think that there's nothing too special about paint, you've never used special paint. I want want to tell you about getting a perfect match to your motorcycle's body or fairing color.

If you've had a minor indiscretion, want to touch-up stone chips or paint that new alien lookalike paint combination for your motorcycle, or want to upgrade your 2008 Kawasaki Ninja 250R to the latest color combination, you need to guarantee the color you use is the same as the manufacturer's original shade.

This is where the specialist paint people come in, as they can mix up any paint. If you have a stock motorcycle, there will probably already be a color code for that machine which will make life very easy.

<img width="200" height="142" class="floatleft" src="https://motorcycleinth.com/images/articles/What-is-your-Tire-Pressure_Waist-Energy_1.jpg" alt="" />It's such a no-brainer we're actually a little embarrassed to mention it. But judging by the number of people we have checked at the PTT petrol-station on Rama 2 Road today, plus some stories we encountered on the street, it's worth repeating. Make sure you have the right tires on your motorcycle, and check if they are mounted correctly and that they're set to the right pressures! It couldn't be simpler, yet people screw it up all the time.

If your tires are under-inflated, then every time the wheel turns a larger-than-normal part of the tire is distorted into a flatter contact patch. Secondly, when ask a dealer to mount new tires on your bike double check to be sure the arrows on the sidewall are pointing toward the right direction. Your tires will wear much faster if mounted incorrectly.