2006 Apex backfires

[Murse]

I would not tighten those clamps on the titanium stock y pipes you will for sure crack them. I f you have stainless shouldn't have tighten the crap out of them too much just to stock.

 

[DigitalFusion]

im sorry, but I would have a really hard time trusting any dealer who went straight to it being a valve issue (at 8,000 nonetheless?!?!?!)

 

[UP Michigan rider]

This is a motorcycle engine we are talking about and 8000 miles is nothing. The engine is indestructible. Backfire is from lack of fuel not too much fuel. Is it hard to start? You might not be getting enough fuel.

An engine can backfire for a few reasons.

1. Lack of fuel.
2. Improper timing.
3. Improper firing order.
4. Stuck or damaged valve.

 

[UP Michigan rider]

Works fine as long as you do not let off throttle for extended period of time coming down from higher speed.

I just reread your post and the sentence you wrote backs up my theory that you have a fuel starvation problem. I think your engine is running too lean, it isn't burning enough gas for the amount of air that is being drawn into it. I will be interested to hear what the dealer finds

 

[Bigdog39]

New spark plugs installed 1000 mile ago. I will have spark plug wires and plugs checked before tearing into engine.

 

[Bigdog39]

Spark plugs changed 1000 miles ago. Will have mechanic check spark plugs and wires and I will check out putting balls in exhaust to see if engine shuts down.

 

[Bigdog39]

Mechanic a dealership listened to Apex for 10 seconds. Said you have an exhaust problem. Next day he pulled out exhaust and discovered a big blown out flange section of a y pipe. Flanges on other Y pipe were cracked. The backfiring is due to air being sucked into exhaust thru hole at broken flange area when off the throttle when slowing down. There is actually a negative pressure when off the throttle. If you are off the throttle long enough oxygen mixes with unburned gas and explodes when you get on the gas again. Ordered two new Y pipes and donuts. Should be back running nice and purring like a lion by Friday.

 

[thor452]

exhaust donusts

X5

Told you so.

 

[Bigdog39]

You were right. You would not think it would be the donuts again in only 1000 miles. Turns out the flanges were thin and could have been cracked a little when the new donuts were put in the first time and the dealer did not catch it. Now it should be good for many miles. Love my Apex especially with a TeamFast air wave suspension to give my old bones the softest ride ever and still go fast.

 

[Murse]

hope you got stainless and copper donuts

 

[UP Michigan rider]

Glad to hear there is nothing wrong with the Engine. You have to love these indestructible engines. Great, after reading this post now I am hungry for some Dunkin' Donuts

 

[ersky]

id check the flex pipes at the head 2 of mine where cracked