Okay I think I may have done something stupid(not the first time btw...) I have any 07 FXST Softail Standard, Stock. I bought these new pipes/headers on ebay that said they were off a Softail custom 07. I got them because my rear heat shield was scratched and it looked like they had some aftermarket slip ons that I could use/resell. Okay, so I get them and realize the rear header does not match mine, and the only picture/bike online that I can find that it does match(visually) is the 09 110cu. SE Softail springer. I also notice that the 'slip ons' that I think are aftermarket Pythons are actually the stock ones off again, what it looks like the 09 Springer softail. So I want to confirm that they still 'fit' my bike. They go on fine, but I have to use the new mounting hardware that came with them via. the ebay purchase. I only use the 1 rear header/heat shield as my front HS/header is fine in good condition. I also put on the new slip ons as they look cool and I want to see if they are stock or not... They have same stock sound as my origional pipes, so I think they should be fine they are stock pipes and look cooler then my origional ones.. I think no problem, the header is different shaped but looks good..... Then, I drive my bike to work today and 1/2 way through a 15-20 minute ride my engine light comes on.... I'm frustrated, don't know why this would come on..could it be the change in the header or maybe these 'stock pipes'?? I will be taking them off when I get home and putting my stock ones back on.. gonna test ride it to see if the light comes on again..I guess this would tell me if its the pipes or the header..but I thought maybe some of you guys could help clear my head so I can get something done today...I cant funtion when my baby is sick!!!