Enduro21 takes a detailed look at a KTM 250 EXC TPI built to race (and finish on the podium) at the 2021 ISDE, a two-stroke bolted together with enough technical savvy and skills on the spanners to be a set-up benchmark for any off-roader…

Away from the factory bikes and rental machines in the International Six Days Enduro paddock with their endless supply of parts, the list of well-set-up bikes built to go the distance is a long one. But while some bikes finish the Six Days gasping their last breath, a select few skip happily over the line ready to do it all over again.

Bolting together a bike which can do it all again takes skills on the spanners but crucially experience of what can both commonly and randomly go wrong with an enduro bike and we reckon we found one of the best prepped machines to cross this year’s ISDE finish line in Italy.

This is Rosie Rowett’s KTM 250 EXC TPI just as it left the last motocross test and after taking her to the podium and another hard-earned medal. As ever with our bike features, we’re side-wiping Rosie (no offence!) and focusing on the machine, the parts fitted and the set-up nuggets we can all learn by looking at the finer details. There are lessons we can all learn from, no matter if you ride enduro, trail, hard enduro or whatever else…

Rowett’s 2021 KTM 250 EXC TPI spec list:

• Hel brake & clutch lines
• K-Tech Full suspension ORVS on the front, bladder kit on the rear with 10mm lowering Kit due to Rosie’s height
• P3 master cylinder clamps
• 9mm master cylinder clutch
• Force Accessories clutch cover
• Force Accessories billet throttle housing
• Michelin Enduro tyres and mousses
• Motion Pro throttle tube
• Radiator bottom outlet set at 30 degrees
• Samco cooling system hoses
• KTM Power Parts triple clamps
• Cooling fan and manual override switch
• V-Force 4R reed block fitted
• TM Designs chain guide
• Raptor Titanium footpegs
• Twin Air high-flow filters and cage
• Standard front brake caliper/ Brembo factory rear plus
• DP Brakes pads

Making life easy

Servicing time is short at the ISDE, and time’s even shorter if you crash and break something. That’s why so many bolts and parts on this TPI are lockwired for their life so they couldn’t come loose and try for an extended stay in Italy this summer.

The dedicated pair of hands behind this bike build is “factory Phil”, Rosie’s dad who makes no apologies for the amount of lockwire around their 250 EXC.“It’s peace of mind,” he says, “it’s easy to just do that back home, before the race and then not have to worry about it at the event.” Scan this bike and try and spot where there isn’t any lockwire might be an easier task.

It’s another indication of the difference between the factory bikes at ISDE, and all their parts bins, versus the privateers who work hard on set-up. It’s not that the Rowett’s can’t fix their bike, they just don’t want the additional hassle. There’s enough to worry about at the ISDE withouth constantly having to fix a bike problem.

Check this mod on the side panels…

Team Rowett have looked at the standard KTM side panel mountings and decided they needed a twist. The side panels are attached by the two upper bolts into the tank like normal but Phil has removed the two inside, connected to the radiator and replaced them with side stand rubbers.

The rubbers pull through the bolt holes and run across the front of the radiator guard to clip on an aluminium brace against the frame.

The side panels sit tight but can also be easily unclipped to gain access to a radiator or simply remove mud or grass build-up behind the rad guard.

While you’re poking around this area of the bike you’ll spot Phil has also fitted two tether cables – the type you fit to the rear brake lever tip and join to the nearest engine bolt – to the radiator and oil filler caps. “That’s a simple one, it just means we don’t drop or lose the filler caps when we top up in a hurry.” Adds Phil.

30-degree angle lower radiator pipe

One modification high up the smart ideas list is a mod to the left side, lower radiator exit pipe. It’s one of those things you wouldn’t even think about until you have the same thing happen as Rosie did on her first ride on this TPI.

“I basically hit a rock,” Rosie explains, “and it pushed the radiator back against the engine. It didn’t bend or break anything, but they flex on their mounting points and it pushed the lower hose against a bolt head and that put a hole in the hose. It wasn’t bad but was enough to stop me riding.”

Luckily this happened while training but it’s just the kind of thing which can put you out of an event like the ISDE and when you’re in podium contention, you don’t want to take that chance. 

Their solution is to get a radiator specialist to make a small alteration to the exit angle of the lower pipe on the left side radiator. As standard it points horizontally but they’ve removed and re-welded the pipe at a 30 degree angle.

With tougher Samco hoses fitted (removing the bulky thermostat in the process), that lower pipe heads across the front of the engine at a different trajectory, missing the offending bolt (which they ground away a little as well).

Stronger union

You have to look closely for some of the clever mods here, like the tweak to the fuel pipe at the bottom lug of the tank (lower left side). The stock pipe exits rearwards, does a 90 degree turn and heads to the throttle body. Phil has replaced the stock part for a stronger aluminium one and turned it on the union to head straight towards the throttle body.

There’s another ‘tweak’ lurking under the TPI throttle body too, a manual screw to adjust the idle. “We had a problem with the bike not wanting to idle after you clock up a few hours. So this just helps to let us adjust it if we need to and stop it cutting out when I’m riding.” Explains Rosie.

(More images are in the scroll gallery at the top of this article)

Quick-release clutch hose 

This is a quick solution if you crashes and breaks a clutch master cylinder or snag the hydraulic clutch hose. A quick release hose joint using HEL hoses, just behind the headstock, means the master cylinder and top section of the clutch hose can be removed as one unit and quickly replaced without the need for bleeding or full hose replacement.

They also run a 9mm bore master cylinder, which is a common modification to make the lever feel lighter.

K-Tech Suspension

Perhaps best known for their British Superbike and Isle of Man TT road racing expertise, K-Tech tune the springers on off-road bikes too and have helped Rosie set-up her bike to suit her light weight and height.

They run lighter springs in the front and rear plus K-Tech’s own ORVS (Off-Road Valve System) with fork top adjusters in the forks and a bladder kit in the shock absorber which is better equipped to cope with heat build-up than the OE WP part. The shock is also set 10mm lower to reduce the seat height for Rosie.

Simple wiring mods

Apart from the smart LED headlight, the electrics are not modified except to fit a manual override switch to operate the fan and moving the light cluster from the handlebars.

Many EXC owners will know a fan is not standard but is an easy retro fit and was necessary in Italy where cool air was at a premium in the extremely dusty tests and transfers. The manual fan switch sits just behind the front number board.

Switches? They’re mandatory for FIM events and not having working lights caught a few people out at the scrutineering in Rivanazzano paddock (another reason to replace the headlight with an LED one). The switch cluster is moved from the handlebars, where it is more likely to get smashed, and also tucked behind the front number board.

The dust in Italy was horrendous as anyone who was there will tell you and Rosie was changing air filters and covers as often as they could – basically every service point. They use the Twin Air filter cage under the filter but also the hairnet-type cover over the top which Rosie says they replaced even more often as it was like a first defence against the dust (and a quicker change). 

Further down the intake line from the airbox is a VForce 4R reed block which improves the ‘carburation’ compared to the stock part. Blowing out the other side of the cylinder, the exhaust system is standard except for the stronger exhaust flange guard to protect against the potential for the dreaded cylinder head damage if you bash the pipe hard.

This is our second bike this year…

How are they liking the 250 TPI model? “It makes life so much easier,” says Rosie who rode the carburetted 125 before switching to the 150 TPI when they came out ahead of this 250. “It is better for the obvious reasons of having more power without being much heavier.” She adds. “When you’re competing against the other women in the World’s [EnduroGP] you need that extra power because they’re all on 250s.

“I’m more of a two-stroke person really but having said that we’re going to try a 250F over this winter period to see how I get on because all the other people I’m racing against are on four-strokes.”

Bolt-on protection

A lot of the parts on this 250 EXC are easy to source but the Rowett philosophy seems to be more about getting the right part for the job and not necessarily going for a list of bits from one manufacturer or sponsor (in fact, plenty of the parts on their bike are bought and paid for).

The front disc is shrouded in the KTM Powerparts disc guard and they don’t run a rear disc guard but do have a sturdy, home-made rear caliper protector. Rosie is happy with the stock front brake caliper but prefers the extra power of the Brembo Factory part for more power on the foot brake, plus they use DP Brakes pads.

The sump guard is the Acerbis carbon one which is light but notable for being really good at enveloping the vulnerable engine cases, water pump housing and even the footrest mount lugs on the frame. They also fit an Acerbis flywheel cover and a heavier duty Force Accessories cover on the clutch side.

A pair of P3 master cylinder clamps are hardly visible but they basically fill in the gap between the master cylinder reservoir and the handlebars. They reduce the chances of a heavy whack to the bars pushing the clutch or brake master cylinder against the bars.

Whose bike is this really?

It might be more accurate to say this is Phil and Rosie’s 250 TPI. Phil has “just a few years” of riding off-road himself and has amassed plenty of experience which he puts into making sure his daughter’s bikes are in prime condition as she claims ISDE medals and finishes fourth in this season’s Enduro Women’s World Championship. 

For a pretty standard bike there’s a hell of a lot going on here which is far from stock! It made fascinating viewing and it was clear the longer we looked, the more we’d find.

A lot of the prep time for Phil Rowett is about making sure the bike is bulletproof for Rosie to do her job but there are some smart and practical fixes here too. The potential for a radiator pipe to so easily hit against the cylinder bolt and split was a new one on us and made us think. The side panel mod with the sidestand rubbers is just a plain and simple good idea.

Apart from that, who’s not inspired to #bemorephil get a bit busier with the lockwire pliers?!

Photo Credit: Enduro21