APEX MISFIRE,HELP!

[MikeChorn]

Need ideas! stock 2011 ape xtx ran perfect, installed a new MBRP muffler and now has a misfire only on near or wide open throttle, no trouble codes, all appears normal.

 

[steiner]

Sounds like the exhaust gaskets may have gotten compromised doing the install. Try the "rag" test and see if the engine stalls or continues to run.

Side note. Was just in Narol yesterday helping a buddy pick up an Attak that was for sale there.

 

[vx700xtc]

Rev limiter?

 

[stevewithOCD]

It ran perfect until you changed the muffler.
Start with the assumption that YOU did something.
Put 2 rags over the exhaust. It should stall in a few seconds. If not, YOU made a leak.
If it does stall, get back to us & we'll take it from there.

Oh BTW: WELCOME Mr first post Mike

 

[MikeChorn]

Thanks all, no exhaust leaks, replaced all donuts in the process, think i'm on to something now. Pulled all plugs and seems to be lean, looks like i've got to turn up the fuel, for sure more air flow with the exhaust so likely not enough juice at full throttle.

 

[Stubbs]

2011+ Apex’s were very lean up top out of the box. Sounds like you may need a PCV for correcting the AFR with the new exhaust. You may also want to add some mass to the tips of your flyweights in the clutch to keep the RPM down where it belongs.