The Library of All Knowledge

To Mod or Not to Mod?

Cheap tricks on how to avoid spending big bucks!

First off make sure that the bike works properly.  You might find that simple maintenance would have the desired effect. (I once replaced a shot KIPS valve on my Kawasaki and gained about 8-10 hp. Not bad for twenty bucks.) Test the bike thoroughly while it is in good condition. Then compare notes with other riders of the same model for bike and see what they have done. You might find that some mods don't deliver the performance they promise. Also look at cheaper alternatives. You should consider configuring the controls and suspension first.  This will give you the ability to control the bike at faster speeds. Then if you're considering engine modifications then have the bike properly tuned. If you do this right you can improve the engine performance with stock components.

Professional Fine Tuning Tricks

1.) Change gears: Basically when you think of changing gearing you think of two things. To either improve top speed or to lower first gear for tight sections. Professional mechanics have other reasons. The most common approach is gear down by adding a rear sprocket a tooth or two larger than stock. This helps keep the bike on the powerband when upshifting. This pulls the transmission ratios closer and make bikes with narrow powerband a little easier to ride. These also make the bike easy to control in the slick stuff.

2.) Adjust Ignition timing: Most bikes have the ignition timing set for everybody. But you can set it to give a little more snap. (But you can also botch it and blow up the engine. Consider the effect of a large explosion near a gas tank and your family jewels.)  On machines with left side ignitions loosen off the stator plate mounting bolts. Turn the plate slightly clockwise and listen for pinging when you ride. If it does ping then back it off because you're using too much advance. The amount of advance that you can use depends upon the jetting, fuel quality and engine mods.

3.) Change head pipe volume: Add some more gaskets to the head pipe at the exhaust port. This effectively extends the length of the head pipe and provides a stronger bottom end.

4.) Adjust the front forks: Sliding the front forks will steepen the rake angle of the front forks. This will make the bike turn sharper, at the expense of stability.

5.) Adjust the wheelbase: If you run a short wheelbase the bike will turn better. This will also make the rear suspension feel firmer. The bike will have the tendency to wheelie a bit better. If your prefer stability then extend the wheelbase. Your suspension may feel softer and you won't corner as well.

6.) Check tire pressure: Adjust your tire pressure to suit the riding conditions. In mud I've heard of riders running as low as 8psi. I would settle for 10 to 12psi. This will allow the tire to deform and grab more mud. In hard terrain I would run 15psi so the stiff tube forces the tire into the dirt.

7.) Adjust the carb: Play with the airscrew. It's key for getting crisp, quick throttle response. It's simple. Warm up your bike, then while holding the throttle open so it idles, turn the airscrew in until the rpm’s start to die. Then back the screw out until the rpm’s peak. Then set the idle speed adjustment. If the ideal airscrew setting is less than one turn out, you need a larger pilot jet. If the setting is more than two and a half turns then your need a smaller pilot jet.

Contents Copyright (C) Michael Fodor 2012.