| Author | Message | ||
     Bigdog_tim |
Still trying to figure out the front brake pulse on my M2. Can someone point me to an easy test to determine if the rotor is warped? Thanks, | ||
| Dentfixer |
I believe you need to lay it out on a surface plate and check it with flat feeler strips. Maybe using a plate glass and eyeballing it will tell you something too. | ||
| Ragnagwar |
I'm assuming you would like to do it on the bike. Get the front wheel off the ground, secure the forks so they don't move and give the wheel a spin. Just eyeball the rotor and anything real out of whack should be readily apparent. If it's something not readily obvious you can take any kind of laser device (pointer, level etc.)fix it to something solid, line it up with the edge of the rotor and give it a spin again. That will reveal just about any problem. Remember you don't want your forks moving or try to hold your sighting device by hand. I have also used this type of setup to align belts and chains and in my opinion gives reliable results. | ||
| Hexangler |
Yeah, Similar to what Rag said, but also try a machinists dial indicator mounted on a dial indicator base. Or you could try a Sharpie marker on a solid base, and slowly approach the rotor with the pen tip. Hex | ||
| Jadow |
I agree with the dial indicator, but I know the front disc assembly includes small springs under every disc mounting bolt. I have seen 1 or 2 get hung up with dirt,grime & brake dust. so applying the dial or pen can show an area that is stuck and not warped? New mounting hardware with a new disc comes with new springs. By the way, what year M2? the 2000 and up disc is far better than the earlier disc. Upgrade always! | ||
| Reepicheep |
The pads don't have a "return spring" of any kind... so if you squeeze the front brake lever firmly, and let it go, then spin the front tire a few times, the "warped" pistion will push the pads and pistons back into the capiper. Then you should be able to find the "low spot" by eyeball, and stick a feeler guage in there to see how much "gap" the rotor left when the high spot pushed the pistons in. There is probably some variable slop in the system, but it could give you an order of magnitude, especially if somebody with a good rotor would try it and see what kind of feeler gauge they can get in there. You really know this if the rotor is *bent* by a tire installer at your local non Buell HD shop. Pump up the brakes, head down your steep drive way, hit the brakes before you go in the street... and pump pump pump pump pump pump before anything engages. Every stop you have to try and pump the brakes back up (moving the pistons out of the caliper) faster then the bent rotor can push them back out... | ||
| Bigdog_tim |
Ok - thanks to all for offering suggestions. I decided to tackle this problem again (was just living with the pulse all winter and spring). Does anyone know the tolerance for warp? On a dial indicator, it varied about .006 - which I didn't think was that much. I can't find the spec in manual. Assuming that is within spec, what else could be the cause? Brake pads are virtually new (have about 1500 miles on them). | ||
| Bad_karma |
Timothy This maybe a build up of pad material not necessarily a warped rotor. Joe |
