Is it worth converting a motocross bike into an enduro bike, a GNCC racer or a woods bike? In some cases, yes. A motocross bike is very light, cheap, and has fewer things to break. And the extra power and firmer suspension might suit the experienced aggressive rider who is racing. The test bike for this vid was kindly supplied by Rob Ferrington from Queensland Offroad Tyres:

But the light weight and racing pedigree of a motocross bike has disadvantages for enduro or GNCC racing. Motocross bikes aren’t plated which restricts where you can ride them legally. In many cases you’ll have a non o-ring chain, close ratio gearbox, small fuel and oil capacity, no electric start and that 19 inch rear wheel is more likely to get punctures and restrict your choice of rear tyres – not good for enduro, GNCC or a woods bike. And the race tuning and firmer suspension of a motocross bike can be a real problem for less experienced riders in the woods.

So it all comes down to your budget, where you want to ride and how you want to ride. Some riders find that by the time they do their motocross enduro conversion they have wiped out any savings made buying a cheap motocross bike… and they still have a close ratio gearbox which isn’t great on a woods bike. Then again, some guys just love tinkering and modifying so here are the usual mods to make an enduro or woods bike out of a motocross bike.

Flywheel weight
Adjust powervalve (some two strokes)
Skid plate, radiator & hand guards
Lower gearing
Spark arrestor

Suspension changes
18″ rear wheel
O-ring chain
Auto clutch with higher gearing
Lighting coil
G2 Throttle Tamer
Two stroke – pipe change
Two stroke – head mods
Two stroke – low tension reeds

Today I get to ride the YZ250 belonging to a well known local gumby, Rob Ferrington who is Queensland’s Goldentyre distributor and owner of Queensland Offroad Tyres. Rob lists the mods he’s done, then I’ll get to ride the beast and see what I think of it.

My first impressions on Rob’s motocross enduro conversion? Very very nice. Rob’s mods have given the little 250 plenty of grunt and a very meaty midrange. I’d be tempted to put an even heavier flywheel in just to suit my style of riding, but love the engine overall. The YZ250 is known for great suspension already, but it’s like a magic carpet ride with whatever tweaks FFRC made… very plush. You can see why they are popular in GNCC racing.

The YZ250 has a dry weight of only 96kg or 212lb so it is feels ridiculously light and nimble. For tight single track or extreme enduro terrain you can see why light weight is the holy grail and these motocross enduro conversions are popular.

Rob doesn’t mind constantly changing gear and likes how the close ratio gearbox ensures the perfect gear, but I really missed the wider gear ratios of a proper enduro bike. Plus the Yamaha still only has a five speed box which limits it even more. Some riders go the option of higher gearing then fitting an autoclutch for the slow stuff… an expensive compromise solution at best.

Is it worth converting a motocross bike to an enduro bike? Sadly in most of Australia there are few places you can legally ride an unplated bike. But other countries like the US have plenty of GNCC events and places to ride an unplated bike. If you are on an extreme budget and can live with the compromises it makes a lot of sense. Or for the competent aggressive rider, it could be a nearly ideal solution. And of course some guys love a project bike and don’t mind throwing money at something like this. But of course it can make far more sense to just buy an enduro bike then strip it back to save weight and put a lithium battery in it. Got any further tips, mods or suggestions? Let me know.

Questions about this YZ250 conversion can be directed to Rob Ferrington at


TheRiddickFarm says:

here in Colorado if you have a spark arrestor you are good to go! we can even ride any ohv In our town and use a few highway sections for access to more trails without any license on the machine. thanks for the awesome channel! I’ve learned much from your lessons.

d1977j says:

What xactly did he do to the head, fix squish probably, but for enduro did he increase or reduce compression. I presume increase for low end.

Trevor Sigmon says:

Rob ferrington? that’s not how you pronounce Vladimir Putin

2Wheels 4Life says:

I prefer motocross bikes as enduro bikes actually, plus in Canada , in my province anyways u cant make a 2 stroke off road bike street legal anyways so that dosent matter to me, I got a 2017 ktm 150 sx , with a lectron mule hv carb on it, vforce4r reeds, a fmf 2.1 powercore, 10 oz flywheel weight, and got the mapping wire unplugged for the softer hit and let me tell u its a woods weapon , going to put the fmf gnarly pipe and vhm head on it next, but evn right now it has a ton of power and is stupid light, not even 200 lbs,

Thomas Wunner says:

Yamaha lost my trust. Why? They are not able to build a serious dirt bike! The YZ is pretty good, but that’s the one and only bike from Yamaha. I used to drive an XT 125 R for my first enduro experience. Well, for the beginning it was a good bike. But if you go harder 10 horse power are just not enough. Also the frame is not meant to jump or to do hard enduro stuff. The next generation bike from Yamaha, the WR did not really the big change. It was a bit better, but can not call it a hard enduro. So, Yamaha, I’m definitively out.

iEatVodka 69 says:

you can get a rec reg kit tho

RXV 963 says:

I think no matter what, we as guys are going to modify the !@#$ out of our bikes.
It could be a full blown race bike from KTM / Beta, and I’d probably find something i’d want to modify.
Find something that fits you in your style and go from there.
Don’t worry about money, it grows from a few trees in my back yard

John Fraser says:

you can put an O-ring chain on any bike, am I wrong?

Google User says:

I just picked up a yz250 2003 and will do some enduro mods. Can you provide more detail on a proper header pipe for enduro style riding? What characteristics should I be looking for in a new pipe? Thanks!!!!


I have a fully converted KTM250sx for single track and enduro with tons of mods.

I am interested in how that head was machined and what he was aiming for. Basically the 250sx is a rocket, looking into dropping a 250xc head on to tame her down and gain some traction

Zedro nurinburg says:

Finally, something that goes with those pants.

Joe L says:

I had a converted yz250 for a long time that was used as a trail/xtraining bike.  It was a love and hate relationship.  I was never entirely happy with the gearing, there was always a compromise, too short for this, too tall for that ect…  Not to mention the resell value of a $2000 bike that you put $2000 into is still pretty much $2000

spacebartabenter says:

absolutely awesome video mate, covered just about everything and very good points.

Jacare1973 says:

That KX500 is a thing of beauty! I would rather ride that!

Animalmother85 says:

Hey Barry,
I have a 2003 YZ250 her in the states, which my friends and I have affectionately named ‘The Donkey’ because when I bought it last spring, I it was in incredibly rough shape (SAE hardware where it should have been metric, suspension was all screwed up, etc). I wanted a steel framed bike over a Aluminum for trail riding and the engines are relatively the same from 2003-2016, so there are tons of parts out there.

Anyhow, I ride trails, not that the fruitier equestrian dressage of motorcycle riding which is known as motocross.

Here are my mods to date;
9oz flywheel weight
Lectron Carburator – totally changed the power delivery to be more trail friendly, added about 10 MPG = 28.2 litres per 100 kms and is easier to tune
GT216AA fatty front – really plants the bike and keeps it from washing out
your typical armor products, skid plates, case saver, etc.
Tall seat
It came with an X-ring chain.

I’ll be doing some more work to it this spring, but I’ll eventually hit the wall of “how much more money do I want to put into a 13 year old bike?”

Future mods include
head work
KYB SSS suspension
18″ rear wheel with GT230
Steering stabilzer
Fasst Co bards

I was just riding with a friend last night who picked up a YZ250FX. His bike has as follows;
power generation strong enough for a radiator fan and headlight
6 gears wide ratio
18″ tire
electric start

I said the same things to him that you mentioned; the YZ250X needs:
6 wide ratio gears
Larger Tank
Electric Start
49 more CCs
Hydraulic Clutch

The issue is with the US market, most people only know Red, Green, Blue, and Yellow with Orange becoming more familiar. Only small handfuls are paying in depth attention to KTM/Husqvarana, Beta, Gas Gas, Sherco, and TM. However, we are starting to see a slight shift to off road riding due to the fact that people are waking up and realizing that their hopes, dreams, and aspirations of becoming the next Travis Pastrana are not grounded in reality.

Yamaha has been doing some interesting things over the past few years. Maybe they’ll pony up. Personally I’d like to see them go to a steel frame for the X model, like KTM and Beta.

Jack Richter says:

I have a 03 YZ250 similar mods but with the long range tank , for the gear ratio’s you can use the YZ 426 no 3-4 and 5 gears to make the WR gearbox, it works great.

Moto Tayls says:

I got a KXF250 first when I started to ride dirt but found it very difficult to ride (not impossible). After swapping to a wr250F I was immediately riding better/faster and with more confidence on the first ride than I ever did with the KXF250. I think mostly due to not having such a snappy throttle I was able to relax and focus on riding, not hanging on with a death grip. What parts on an enduro bike would you suggest stripping to save weight besides lights?. Thanks 🙂

Scott McHone says:

I started out riding pretty technical single track on a kx250. I added an 11oz flywheel weight and moose racing makes an easy pull clutch lever that really helped the wrist cramping. Some guards and a skid plate for protection. The suspension was stiff and kick starting the bike in the middle of a technical uphill section was tricky. But it got me addicted to this stuff at a price I could afford. Though I have to admit the first time I went out on my 300 XCW it felt like I was floating over some of the stuff that I had struggled over on the Kawi.

Mark - says:

I own an older YZ250 and finally converted it to a woods bike a few years ago (pipe, weight, suspension, chain, steel sprockets, and few other changes), and I have to agree that you’re much better off performance-wise getting a full enduro bike. Mine does fairly well and can tractor up most technical stuff (mostly due to 13/50 sprockets), but it’s not the easiest bike to ride compared to others (which, since I need the exercise, suits me). I also don’t have the advantage of that lower 1st or higher 5th gear.

The differences between track and enduro bike engines (especially 2-strokes) are the porting, timing of the power valve and spark, and carb size (lower rpms require smaller carbs in order to maintain intake velocity). Until those changes are made, a track bike will never equal the low-end grunt of something like your 300 Beta.

Also, I think most will find that there’s little weight difference by the time many of those changes are made.

Brennan Paden says:

Not sure if someone already said it, but Rocky Mountain ATV has a wide range gear conversion kit so your YZ250 will have gearing like a YZ250X.

Ian says:

My YZ295 has a 295 kit, re ported, reshaped head, fmf gnarly and Shorty, 11oz flywheel weight, torque spacer, different needle, bigger rear wheel, throttle tamer, mousse tire, and it has wr450 gears in the gearbox

Eddi Nice says:

Hello guys, great video.

I am interested in buying YZ250 between 2006 and 2016, my budget is £2500. I would like to make it enduro-friendly, sort of like KTM 250EXC, but cheaper. Can you guy help. Thank you

James Kelly says:

Love your videos! Great job

 Write a comment


Do you like our videos?
Do you want to see more like that?

Please click below to support us on Facebook!