Like I said, I had quite a bit of trouble getting my HMF pipe on my wolverine...BUT, I dont remember there being a whole lot of pressure on the head pipe.....my troubles were with the mounting holes. I had to get one bolt in (Just started, not tight) and then fight with it until I was able to get the other bolt in..then I tightened both of them up, and then tightened the clamp on the head pipe. I have quite a few hours on mine since the instal, and not one problem yet because of it.
Where did you buy your pipe from? I got mine from Ebay, and it did come with a HMF 145 main jet...I also picked up a dynojet kit for the wolvy because I wasn't sure if the pipe would come with one or not...but I still have the jet somewhere in my garage, I would be more than happy to send it to you if you want.