Topic: Changed exhaust, idles different and sounds funny?????

[manjisann]

My bike had the old four into four when I took it to the mechanic.  They tuned it up and it sounded great at the shop. When I got it home I took off the exhaust and put the new four into two I had ordered from dennis kirk. It is a mac slip on. I asked mac if I would have to rejet if I did this and they said no. When I went to start it was hard to start, and required fiddling with the idle screw. It also sounds a little different up front. I am wondering if I have an exhaust leak as I didn't change the gaskets when I remounted it. So, could the starting problem be an exhaust leak, or is it the new pipes, or something else. Thoughts??

Thanks,
Brandon

[mattcb350f]

The four into one might make the jetting a little off, but I'm not sure that it would change how it starts though.

I suspect the tune up the mechanic did changed how it starts cold which, I assume the first cold start after the tune up was with the MAC system?

Should probably get some new gaskets too. They're cheap and will seal up any leaks you might be having.

 Matt.

[nteek754]

Matt my guess is the four into two made it a bit richer but thats a guess not sure enough to say put smaller main jets in now for years I have changed to a kerker on three differant 750s taken baffle out run just the cone piece in it and they all run super (no jetting). and yes if you have a leak up front that can mess things up so Id say seal the leaks then see what you get. good luck Craig in Maine

[manjisann]

Thanks both, I will put new exhaust gaskets in and see what I get. cross my fingers that it fixes most of the problems.  When I started it at the shop it still had the four into four, but it started on the first kick. I just tried getting it to start this morning, and it sounded like it wanted to catch a couple times, but never really took off. Maybe with the leaks there isn't enough back pressure for it to work. I don't really know much about exhaust systems, but what I have read says you have to have some back pressure for everything to work right. I'll let you know how it turns out.

[manjisann]

   So, I changed the exhaust gaskets and lo and behold, starts real easy. Hooray!!