I have a 1985 XJ700 Maxim N (Air cooled) , the exhaust was U/S so I bought a mac 4 into 2 set

I now have problems with low end power and it splutters terible at 6500rpm

I was told when I bought them that they were the same for the X (water cooled) or the N (air cooled)

Does anyone know?

Also I have contacted MAC Exhausts and they assure me that it does not need rejetting?


Please help a lost soul..... :(

Does running with some choke on help the low end at all?

no it makes it worse

I would say that if it was running clean before the swap, and there were no other changes, that it must need re-jetting no matter what Mac says. What you are describing is classic symtoms of mixture problems after the installation of a new pipe.

Funny, if you don't need to re-jet after installing an aftermarket pipe, then the pipe is no more efficient then the stock one was. If that's the case then what's the point?.......... B)

i would have to agree with whisperer on this one if it ran fine before and dont now it needs rejetted always had to do this growing up on my yz 250 and my xt500 when i changed silencers let alone pipes.

Thanks Guys, You have answered my thoughts. :o)

I now have to concider what jets to use? I have a bank of carbs of an XJ750J in good order.

Worth a try you think?

I just say put those kn stage 3 kits on the carbs myself always had good luck with them. And i believe swapping carbs isn't going to change much just rejet and since your that far clean and adjust the carbs. I do most of my own wrenching so i dont know how much shops charge if your not up to the task (no offense ment I was raised by a truck driver and my grandfather owned a 300 acre farm.)