Hey guys,

have moved from NE Vic to Brisbane, my EVO is really backfiring a lot now that i'm by the coast, well I think the alttiude change is causing the back fire.

Did a plug chop on a HD plug 5R6A pics below, has really white top but with a little soot around thread, I think it looks oK maybe a little in the lean side?

Would an incorrect mixer setting cause it to backfire, have a screaming eagle hi flow Air cleaner, all the hoses are tight with no leaks around the carby.

Have always run uppercylinder lube on this engine, has done around 30K, when you light it up and hit 60 MPH and then back off the thing lets off 3 or 4 backfires then it sometimes barks out the carby, bit strange , any thoughts?

 

 

hi  maybe replace the inlet manifold seals to the cly heads  if thay are over 6yrs old ? also check voes  hose  then clean out the fuel system & check the jets  etc 1st

 Thanks Kiwiwdave & daddy racer,

Kiwidave, the SE kit was installed back in 98, motor hasn't been touched in years, only stuck it on a trailer recently to move it up here.

Will  pull off carb and manifold etc to check all the seals. Maybe somethings perished over time.

tks again

The Plug color looks right, Could be you Fuel,,,,,,,,, Unleaded only has a short Life span,,, If the Bike has been sitting for more than 2 months I would be dumping it....
Also check the Exhaust Flanges, Start the Bike up Cold and just run your hand around the Flanges,,,,,,,,, Leaking Exhaust Flanges with cause Back Fire like your got

 Thanks fellas,

pulled all the carby and air kit off, was fine with jetting 50 idler and 180 main, couldn't remember what I jetted it with, so was could to note down for future.

Turned out to be a slight leak on front header when cold,, all fixed tks 

So do I win a Prize ?