What make are they although I am not sure if that makes a difference.
I fitted R&G crash bungs on my K4 and I had to replace the main engine bolt with the bolt supplied by them. A little daunting pushing the main bolt out but as long as you slide the replacement in at the same time there is no problem. Also make sure you have two socket wrenches (I believe they are 19mm) as you need to tighten/unsrew the bolts at the same time on each side
Here is a link to the fitting instructions on the R&G website. It might give you some idea of what I am trying to say
http://www.rg-racing.com/Images/Prod.../pdf200_60.pdf
Hope this helps dude