1500 mile update (in 10 weeks). I must be -kin- unlucky, the rear disc has warped and brake lever pulses lightly, dealer to replace under warranty. Never had a warped one before, even on 140mph track days on Bandit 1200 and discs went rainbowy blue. It just happened out of the blue mid journey. Weird.

Apart from that brill scoot @ 75mpg which I expect to improve with warmer weather. More kick when overtaking anywhere in the 35-75 range. Hand filed some more off the main stand feet and now does not hit the tarmac.

Bad luck with the disc. Maybe it's the hardening of the disc metal which is at fault. I've had the same happen on all sorts of bikes.
I've just been reading a "Winter test" done in MSL magazine were they compared a ride to Skegvegas on an XMax 400 and an a 390 KTM. Hardly a comparative test but I know which I'd have sooner been on.

You are not the first regarding the rear disc. I've a mate with a 2017 X Max 125 and he's also had rear disc replaced under warranty.

Strange one that regarding the disc. I have owned both a 2017 X-Max 125 and this years X-Max 400 and no problems with either.....

Bad luck indeed :/

Edit: Hmm.... Just been reading a few articles on the internet and it seems that some dealers are wrongly diagnosing discs as warped on all makes/models of bike. The same symptoms could be due to various issues including heat, wheel not true, pads wearing unevenly etc. I will be sure to be aware of how my brakes feel in future though and will let you know if I experience the same problem...

Spoogle wrote: Edit: Hmm.... Just been reading a few articles on the internet and it seems that some dealers are wrongly diagnosing discs as warped on all makes/models of bike. The same symptoms could be due to various issues including heat, wheel not true, pads wearing unevenly etc. I will be sure to be aware of how my brakes feel in future though and will let you know if I experience the same problem...

You'd have thought it'd be fairly easy to diagnose...a feeling of pulsing through the brake lever is a good indication of a warped disk, though I guess it doesn't preclude other issues.

Spin the wheel with a dial guage on the disk...
Or hold a piece of card?... Not hard

Yes MrGrumpy and Paul you are both right; it should be easy to diagnose if correct procedures are followed, however we all know that is not always the case lol. As for pulsing through the brake lever being a good indication of a warped disc, it could also be caused by uneven patches of friction material from the brake pads on the surface of the disc for example.

Occasionaly we would get a car in that had pulsing through the brake pedal, sometimes it was a warped disc, but more often it was hard & soft areas of the disc causing unequal wear. The hard & soft areas were caused by hard braking heating the disc, not a problem in itself but it became a problem when with the car stationary, instead of applying the handbrake which would allow the disc to cool evenly, the driver had held the car on the footbrake & caused localised chilling of the disc, hence the hard & soft areas.
So as well as checking with a dial guage for runout, it would be advisable to check for even thickness with a micrometer or vernier guage

I've had a few bikes with a warped disc, a ZZR600 and a 918 Fireblade, both diagnosed by the pulsing through the lever, both cured by new discs. I'm not saying it couldn't be anything else, but my interpretation of a pulsing lever would be a warped disc.

Oddly, I've had very few disks that have become warped in use, but several that were warped from new!!