i just bought a cat d5lgp runs good but it has system one undercarriage an 1 of the front idlers has humps on it does that mean it is wore out I haven't seen that before.
I haven't been around System one but maybe this could be similar to the scalloping you sometimes see on standard rails? We had a D7H we were using as a push cat. It started that stupid wear on the track links. We decided it most likely was caused by too high of travel speeds. The operator was running flat out 3rd gear backing up after every push. I'm not sure if it would be comparable to what your seeing but sounds possible since the wear characteristics are similar and the bushings are probably contacting the same places each time around the idler.
I would suggest a good starting point would be to contact your local Cat dealer and ask them to send someone out to do a complete measurement of the undercarriage (this will include every component in the undercarriage system) and produce a Custom Track Service (CTS) report. If you give them the impression that you're planning on buying new undercarriage from them then the report will be done at no cost to you and in double quick time. Once you have that document post the results back here. After receiving the report go back to the dealer and ask if there are any Caterpillar factory support program for your particular S/N of tractor. Earlier versions of System One undercarriage had "issues" and Cat do support them with factory programs to either upgrade to the latest version of System One or switch to conventional undercarriage.
I've seen some some that looked darn near like sprockets. In system one, since the idlers run on the bushings and not the links, the wear can be quite uneven. Best to do as nige said and get a dealer PsSR to come take a few measurments.
There are several versions of System 1 running gear, specifically some come with a narrow scalloped idler that runs on the bush rather than the rail. To my mind this gives the roughest ride of any configuration. I think that's what you've got there. I'd still go with Nige's suggestion that you get the full measurement done.