u/cnkcnkcnk

Recently i noticed that every 6 days i have transaction which is sending 0.09ERG somewhere, im using Terminus, any ideas whats going on? It happens since 9 Feb 2026

Hi, i think i tried everything so will ask you guys for some input, help or ideas. I race track only Yamaha R3, fully built suspension, engine etc but brakes are stock due to racing regulations, only pads are different (I was using SBS DC for last 2 years). Some time ago i started to feel weird judder of whole front end when braking, specially when trailbraking far into corner on some lean angle, at first i thought that my front disc bobbins are worn out too much (they were really loose), so replaced front disc for almost new oem rotor (probably taken out of a showroom bike or something like that - still had these marks of factory machining). After mounting this new rotor still had the same judder, i can describe it like pulsating lever which leads to whole front end suspension vibrating up and down. It happens after 5-7 fast laps on small local track, before that brakes are perfectly fine and ideały smooth. After that i measured this „new” disc runout and its about 0.09mm (manual says limit is 0.15mm), thinking that maybe my „new” rotor is somehow not ideal i ordered another one, this time new OEM directly from Yamaha, mounted on wheel and tested runout immediately - result is almost the same - 0.08mm runout on factory new disc. Tested wheel and disc mount holes runout and this is perfectly fine, so looks like rotors from factory with slight runout are standard. In the meantime i also checked head bearings and if head is tightened - that looks ok, head bearings were changed 1yr ago for tapered (btw now im in process going back to stock ball bearings - i think theyre more precise and better for track). Also i tried to scrub brake disc with sandpaper and once again try to bed in SBS DC pads - i feel like nothing changed. Recently changed to SBS RST and then EBC GPFAX and i feel like maybe its a bit better? But im not sure…

So to summarize, what i tested:
- rebuilt front caliper, cleaned pistons etc, works perfectly fine
- i dont think that matter in this case but rebleed everything
- „new” brake disc, bobbins are fine and lets rotor to float
- scrubbing rotor, re-bedding brake pads
- changing front suspension settings
- checking headstock bearings

Question is - would i feel 0.08mm of front disc runout? Even if yes, why i feel it only when brakes get up to temp?