19/08/2024
Write up on my TBI experience so far. 🙂
I’ve ridden 5 x 2024 KTM TBI’s now:
My first TBI bike 2024 - 100hrs
Romania June 2024 hire bike - 15hrs ish
Romaniacs TBI - 35hrs
My friend Stuart's TBI - 5-7hrs
My new 2024 TBI - 3hrs
All 2024 models. :)
It’s the first bike I have owned where within an hour, I can set it up to be EXACTLY the same as the one before. I’ve never been able to do that before and always took me weeks/months to get the same feeling back when switching bikes on the TPI’s and before.
TBI Chassis:
Chassis balance on the new bike is super important. Moving from a PDS bike to Linkage and then back to PDS again has been interesting. SAG plays a major role in the feel of the bike (more so on the PDS version as the rear sits a bit higher), it affects the steering and stability of the bike more than I have experienced before on other chassis.
Front end is higher on the new TBI bikes - so lower bars essential. Renthal 821 Fatbar or Astra Aurora 30mm/28mm are my preferred choices. Incidentally, when using my friend Stuart's bike the first time I had bad wrist pain when riding the bike. 2 differences - he’s running standard springs in his suspension and using Renthal 999 Twinwall handlebars (Renthal 821 Fatbar and 999 Twinwalls are the same bend, the Twinwall is just much stiffer). So I put my own suspension on the bike but still had the wrist pain, so can only put it down to the bar stiffness. I took the crossbar off the Twinwalls which helped a tiny bit with the wrist pain but it’s still too stiff for me. On my new bike (currently standard KTM bar - which is an 821 copy) I am experiencing no wrist pain whatsoever. So for me personally there are 2 drawbacks to the Twinwalls, they limit your lever position choices due to the design and they are way too stiff for my old wrists - so it was a confirmation I won’t use them again. I’d rather ride with more flex, and replace a bent handlebar than have those hassles. Standard KTM bar or Astra for me.
2024 Bike bodywork is narrower than before - I like it, slimmer feeling and playful. Easier to move around on the bike, easy to get forward on the bike but even more important to lock in with your knees. Seat is firmer which I like but some might not.
Plastics are very different, better in some ways. A whole new way of assembly, few more and somewhat unnecessary screws. Jury still out over all.
One pain on the 2024 bike is the way the fuel tank connects to the throttle body, it’s an awkward threading of the fuel tube through the frame. Sometimes a 2 person job. Some people have said the bikes run out of fuel due to the new fuel pickup. I’m glad to say I have not had that issue.
TBI Engine:
TBI Engine characteristics is very different from before. I’ve read that the TBI EXC engine makes around 5-7BHP less than the TPI EXC engine. The internal gearbox ratio is very different so the bikes ship standard with 13:45 gearing. I run 13:47 for regular enduro (Jake still prefers 13:45), and in Romania we used 13:50 (Ben Wibbs used 13:51 which I think might be the magic number for Silver lever trails) for hard enduro.
Very different engine characteristics is in part engine mapping & port timing related. The engine feels ’softer’, smoother and is so much easier to ride than the TPI bikes. Believe me it still makes great power but doesn’t have outright powerful feel of a TPI bike.
Throttle body is different, it’s the one that has been used on 4T’s for a while so you have idle and cold start adjusters. No need for an idle screw mod any more! Throttle cam changed, more twist required of the throttle to achieve the same engine RPM change which makes it easier to ride.
Crank Case Pressure sensor moved to airbox, hopefully solving the unreliability issue of the CCP on the TPI.
TSP setup:
I’m running a full TSP (Two Stroke Performance) setup. You don’t ’need’ it but it makes a noticeable difference to improved power delivery and engine torque feel.
Currently using a Medium head insert & .K ECU Map (GREEN standard and WHITE richer). Used the High insert on my first TBI bike - great feel, the Medium just feels a tiny bit smoother.
I’m also running the TSP Power Valve cover which increases power valve volume - this adds 2BHP BEFORE the power valve opens which means better low down torque - amazing for hard enduro. Used that characteristic a LOT in Romania on the Silver class hills. Just lugging the bike before the PV opens. Never had a single stall. Awesome.
It’s important to set the throttle position up correctly so the TSP maps works optimum, using the TSP ERM model connected to the bike, the TPS (Throttle Position Sensor) needs to be reset to 0.4v super important, idle 0.53v and cold start 0.63v to get it all working right. Then a throttle end point reset and an ECU power reset.
I’m pairing that with the new OXA header exhaust - which has been specifically matched to the new port timing on the TBI’s and the OXA end cans (standard and long which I am still testing). Initial indications are the longer ‘Hard Enduro' version revs out longer and cleaner. Jarvis, Wade, Brightmore’s, etc. all are using the OXA pipes right now. I can feel why. :)
TBI Suspension:
The new 2024 Standard fork is closed cartridge - it’s the best production fork ever on a enduro bike. It’s an improved version of last years WP 6500 cartridge. Amazing. Good enough for most people at most speeds in standard form (with corrects springs for rider weight).
I recently upgraded to WP Pro Cone Valve forks. At very high speeds the mid valve is safer (less deflections) than the CC fork. That’s the only real difference. Incredible fork.
Standard 2024 Rear PDS shock is probably the weakest part of the new bike. It can be massively improved with a bladder kit and revalve but Jake and I both opted for WP Pro rear shocks.
The WP Pro ‘Trax’ shock is UNBELIEVABLE. One of the best upgrades you can make to the new 24+ PDS bikes. Super consistent, planted feel and it rides through hits like nothing I have felt before. I don’t think the 2024 linkage bikes need it as much as the PDS bikes, not sure because I haven't spent much time on a 2024+ TBI linkage bike yet.
Overall the best KTM variant I’ve owned. Took a while to find the 'magic' setup but now that I have, and it’s completely replicable from bike to bike, the bike feels amazing. I feel like I can ride this bike faster than any bike before while maintaining great control and wheel placement accuracy.
The fact that I could hire a brand new bike, put my parts on it and finish Silver class Romaniacs is testament to just how good the new bike is and how replicable the setup is. Super happy. 😁👍👍👍
