Seriously Upgraded KLX 300 for Sale

KLX 300 with New IMS Tank and other goodies

Over the years, when the mood has taken me, I have been into restoring, converting or upgrading motorcycles, Volvo Vintage cars, BMW Vintage cars and the odd Jaguar XJ6 to my exact liking.

Since I have been in the USA, I have only done one recent motorcycle upgrade, but it was a grand old hoot that brought back all the on-the-fly engineering puzzles I seem to enjoy solving with much diligence with add on bits that require some additional out the box engineering Edward De Bono style to get them to work as desired.

Sadly, this latest Motorcycle rebuild project of mine will need to be sold but this KLX 300 has been upgraded specifically for a 6'3, 220 Lbs. Pilot (me) with some very sensible upgrades thrown in with it to make it a very attractive option.

It has served me well to get my US CA M1 License, have fun upgrading the crap out of it and having some serious enduro fun up at Bottle Hill up Sacramento way while I was at it.

I started by specifically looking for a very low mileage KLX specimen in all the cycle trader and online motorcycle classified sites and I found a 2021 candidate in superb condition up in the Aubern, CA area listed on Craigslist, funnily enough.

The guy that owned it was a tiny 115 lbs bloke who literally needed a ladder to get on the darn thing.

He never dropped it, but he did ride it like his grandma would have driven it if she could hypothetically mount it.

I think he never took it over 50 mph in all the time he owned it from new as I had to run it in properly when I got it with 2067 miles on the clock, which was a tad unusual.

The first thing that I upgraded was the standard seat which I still have by the way.

I bought a seat concepts unit for it which is great comfort wise and was highly recommended by my pal Greg Albertyn who was once a world motocross champion for Suzuki.

Greg has great taste, and this seat is lower than standard and is pretty comfortable at the same time.

Next, I added a tail rack which this sort of bike should have as standard gear, and it works really well on this machine. I had to bend a few things for it to fit right though.

Good job I have access to a hydraulic press for that sort of shenanigan!

After that I tackled the tires and changed to Dunlop D606 front and rear with 4mm heavy duty Tusk tubes which is working well both in the dirt and on the road for my particular mix of the two.

Serious off roaders might want to change the front 606 for a Pirelli MT21 though, it's better than the D605 but not as good as the MT21.

Next up, I did the ECU reprogramming right after I did the KDX 200 Snorkel mod and tuned it for my specific dimensions and weight.

I also replaced the standard KLX 300 footpegs with the IMS racing footpegs and this actually makes a huge difference to any KLX 300 on its own as the stock footpegs are a serious joke.

These just took about an hour to fit with most of the time going into the cotter pins on each side of the bike. I struggled to find the right pliers for the job.

I then worked on the risers and handlebars which led to custom cables for the KLX with all of the different types of risers I tried. I was surprised the simplest riser options worked the best on this particular bike but all of them would have needed cable changes!

I also had the wheel bearings replaced with better Swedish bearing units using exotic synthetic grease while I was at it.

I was going to use Japanese bearings, but they were not up to the task or as good as the Swedish fare, so I went agricultural.

I then had the engine gas flowed by my chums in the U.K who do work for Aston Martin and liberated a few HP that way.

I then did some work on the DFI while we did the ECU work - this was quite tricky but once the KDX snorkel and custom air filter was in it became a lot easier.

This all took a fair bit of time on the dyno and required I also upgraded the ignition system with better parts and the spark plug type which is now the Titanium series NGK.

The ECU unit needed a few programming runs to get the right curve that was linear and smooth.

I could have got 7 HP more out of it but the problem was that power curve was ugly and very non-linear.

In the end I went with the best linear curve from the bottom to the top and I am very happy with it.

Then I just had to do something about that puny 1.9 Gallon gas tank joke that it came with care of Kawasaki Engineering.

My pals over at IMS in So Cal were pressed into doing a 3.8 Gallon tank for the KLX 300 series and that has been done in Black so as to avoid CHP scrutiny.

This has made the bike seem a lot wider than the standard rig and is absolutely very cool.

Few folks can tell what this bike is without me telling them either.

There are no Kawasaki markers or logos on this thing by the way but if you are familiar with KLX engines you will know what it is at first glance.

I also decided to get rid of the stock lead acid battery and replace it with a much lighter and more reliable Lithium battery which saved a few lbs to the overall weight.

I also custom padded the plastic covers that rest on the new IMS plastic tank bits while I was at it.

I hate buzzing and bits that vibrate when they shouldn't - drives me nuttier than I already am!

I also played around with various exhaust systems by the way but surprisingly found that I could not tune it as well as the stock pipe, so I stuck with it after several CHP pals of mine said the noise on most of the custom pipes would attract bad attention for the rider from CHP folk who heard it.

I shared the power curve data with them and they also opined that the stock pipe and tuning was the best option they could see from the data anyway.

When they heard the first 4 pipes I tried, they told me I would get pulled over for sure on hearing them all so I think I got it to the best place it can be regardless of any of the other pipe options.

You can get pipes that sound cool but getting one that actually performs better than the stock pipe proved impossible. I spent 33 hours on it with four other pipe manufacturers.

Sounding good and producing the perfectly linear power curve are obviously not the same thing and I prefer smooth linear power to cool sounding audio effects myself....

The KLX is a naturally very quiet bike, not as good as an electric Zero but I can duck hunt with my shotgun on this thing just as quietly.

With 3300 miles on the clock, the exhaust has a long way to go before it needs replacement.

This machine has thus been tuned specifically for a 228 Lb pilot with a full 3.8 Gallon gas tank with noise pollution in mind.

It pulls like a train from low gears all the way to 85 Mph in case you are wondering.

This tune caters specifically to 0-40 Mph dirt bike riding though.

I also added a red KLX bash plate and had to use various rubber dampers to get the vibration issues sorted out. This also took a bit of time to get right, and another 12 hours went into that puzzle.

Front left side view

I also did yellow barkbuster hand guards, new grips, AS3 gear lever and longer clutch cable and I also had stronger springs fitted for the front shocks and the rear springer with 10W fork oil in the front shocks.

I did not like the standard brake and clutch lever at all, so I upgraded them both with much better units.

In all I added $3800 worth of goodies and mods to the machine (with labor), and it is now perfect for trail use or for about farm or town tootles.

I have a farmer who actually wants it, but he does not want to pay for it and I ain't giving it away like this for free!

Where I live in Nor Cal there are scant trails that can be used these days, and I have to drive 100 miles to Bottle Hill for a decent one to have fun on.

I had intended to drive on the many trails I can see from my aircraft, but they have made them inaccessible to dirt bike riders in these parts of Northern California over the years.

For that reason, I am switching to a Husqvarna Swartpilen 2 wheeled adventure bike chariot instead while I rebuild a Buell Ulysses machine for my dimensions.

I change the KLX oil every 500 miles (full synthetic) and check the valve clearances every 1200 miles even though normal service intervals are every 7500 miles.

This machine has all of the custom tuning and upgrades you would need to do if you are a 220 lbs plus Dual Sport nut.

If I had bought a brand new KLX 300 it would have cost me $9500 to ride one off the lot, then I would have had to spend $3800 to get it to where this one is for a total of $13,300.

That seemed like a bad deal to me so for the price of a low mileage specimen plus all the add on goodies I got a better bike than what a brand new 2025 model would have bought me.

Trust me, a standard 2025 KLX 300 with its puny 1.9-gallon gas tank is a thing that irks and eats you alive unless you also have a huge pickup truck with a motocross loader on the back to get it to Enduro trails.

As this is a fully modified low mileage 2021 Camo edition with all the mods, I think my $7200 ask price is actually pretty reasonable.

KLX 300 Clutch side grip, custom clutch lever and Acerbis view

I have done custom builds and mods for various folks participating in competitions like the Paris-Dakar, Roof of Africa and Baja 500 and all my bikes ridden by privateers have finished very well.

I have also upgraded several bikes for myself and my pals over the years with surprising results.

I usually buy these at auction for peanuts and do complete teardowns and rebuild them properly.

I had a winner in 1985 in the roof of Africa with my pal Willie Ireland and I did the setup on that machine for KTM.

When I customize a bike, I go to town on it. This one took me 3 months to upgrade from start to finish and the result is pretty awesome.

I get compliments on how cool it looks all the time.

I need the funds for my next project though, so here we go, one KLX 300 fully modified for a beefy punter.

KLX 300 front brake view

email me @ chaanbeard@me.com if you are interested and make me an offer I have one for $6K but I ain't keen...

FYI, if you did the full suspension tuning yourself with a specialist you would spend $2000 with them to do it properly.

The ECU, DFI and dyno tuning would also set you back a good $2400 all in - mostly labor charges for that bit.

All the other cables, levers, bash plate, electrical upgrades, new bearings and the gas flowing and all would also probably run you north of $2500.

As I did this all myself with my own chums in the biz, I did not have to pay for the labor, just put in the hours and time to get it all done.

With this one all you have to do is just jump on, drive off and enjoy...

Small Pygmy sized riders need not bother making inquiries, it would have to be set back to Japanese rider proportions and weight for this machine to be of any use to you and it has been setup for American dimension riders....