[Philbomoog]

I've just taken off my exhaust while looking for an annoying buzz/rattle sound which I thought may have been coming from the header pipe.

While its off I considered getting rid of the 'hotpipe' restriction thats in there. What effect would this have on the bike's running. Would I have to re-jet? Would it make any difference? Should I bother?

Your thoughts...

[D the D]

Yes, you will have to rejet the carb or it will run lean.  It improves throttle response and power noticeably.  Don't do it unless you can rejet the carb.
Many threads on this, many more on rejetting the carb afterward.  Just do searches for hotpipe and jet.  The threads will tell you what jets to order to get you in the ballpark.

[Superchuck]

I just removed my hotpipe last week in a sequence of mods I'm still in the middle of completing.  The hotpipe was a b!*&% to get out, but after taking that out, jetting the carb higher, and replacing the stock air intake with a K&N variety made a huge improvement.  Most people end up putting in a 17.5 pilot jet and a 120 main jet when doing these mods with the stock AVL carb (Mikuni UCAL BS29).  That's what I'm running now but I'm going to experiment with a larger main jet... still not perfect, but you can infinitely tweak these things and it'll still never be perfect.

[tooseevee]

I just removed my hotpipe last week in a sequence of mods I'm still in the middle of completing.  The hotpipe was a b!*&% to get out, but after taking that out, jetting the carb higher, and replacing the stock air intake with a K&N variety made a huge improvement.  Most people end up putting in a 17.5 pilot jet and a 120 main jet when doing these mods with the stock AVL carb (Mikuni UCAL BS29).  That's what I'm running now but I'm going to experiment with a larger main jet... still not perfect, but you can infinitely tweak these things and it'll still never be perfect.

    I think that's probably true, but we can't always get what we want, but if we try, sometimes, we just might find, we get what we need 

    I think I'm close (although I have not done my main yet); I went down there earlier this evening since the bike has sat since Thursday. Touching nothing, one kick & it was running. That's just not right 

    You would think you'd need two just to suck some gas in...... 

[Philbomoog]

I've put it all back together and left it stock, for now. The annoying buzz turned out to be the oil pipe touching the case.
I may experiment in the future but I don't want to risk messing with something that isn't broke unless I could guarantee some vast improvement.