6.5 clone popping

[Frank Bullitt]

My clone motor pops when I come off throttle. It is stock except I took off the airbox cover and put a header on it with one of those generic briggs mufflers. When I made the header I used the stock flange which is a piece of crap because it is round when the exhaust port is d-shaped. Could this mismatch cause this?

 

[blownengine]

The popping isnt really a problem persay. I actual think its cool. :thefinger: Its just unburnt gas being ignited in the exhaust

 

[Sinner70]

used to do that on my clone, then I put one of those cheap mufflers on the end. Still does it, now only half the time. usually when I let off the throttle going full blast down hill. Shouldn't be a problem. sounds cool too.

 

[typeone]

could be running lean now with an open airbox and pipe. fatten it up a bit and see if the popping on decel clears up.

 

[Strigoi]

you're probably running lean. after messing with the jetting mine doesn't pop very often anymore.

 

[nostrixoxide]

It is common for these little engines to pop like that on decelleration. When you let off of the gas your basically engine braking until the rpm drops low enough for the clutch to disengage. Similar to how a big rig uses a Jake Brake to slow the rig down, except your not restricting the exhaust side of the engine. It really depends on how loud the popping is. If it's sounding like a huge explosion then more then likey it's lean pop...

What you really need to do is make a high speed run on your bike & then kill the engine while the engine is still at high RPM. After that you should pull your spark plug out & check the color. The lighter the color the leaner the engine is running. The absolute best way to run this test would be to get the engine warm by riding it around alittle. Then bring it back into the garage & install a brand new spark plug. Then do the the test & check your plug reading.

White / Light Grey = Too Lean
Tanish Brown = Just about perfect.
Black = Too Rich

Here is a link to better explain this process.

Reading Spark Plugs Correctly

 

[Sinner70]

It is common for these little engines to pop like that on decelleration. When you let off of the gas your basically engine braking until the rpm drops low enough for the clutch to disengage. Similar to how a big rig uses a Jake Brake to slow the rig down, except your not restricting the exhaust side of the engine. It really depends on how loud the popping is. If it's sounding like a huge explosion then more then likey it's lean pop...

What you really need to do is make a high speed run on your bike & then kill the engine while the engine is still at high RPM. After that you should pull your spark plug out & check the color. The lighter the color the leaner the engine is running. The absolute best way to run this test would be to get the engine warm by riding it around alittle. Then bring it back into the garage & install a brand new spark plug. Then do the the test & check your plug reading.

White / Light Grey = Too Lean
Tanish Brown = Just about perfect.
Black = Too Rich

Here is a link to better explain this process.

Reading Spark Plugs Correctly

:thumbsup:couldn't have said it better myself. and thanks for the link.

 

[nostrixoxide]

No problem Sir, glad I could be of some assistance :drinkup:

 

[Frank Bullitt]

awesome thank you for the most excellent tech info. It isn't really loud or really even annoying. I just figured it might be a symptom of improper carb tuning or something and didn't want to keep running it if it is causing damage or something.

 

[nostrixoxide]

awesome thank you for the most excellent tech info. It isn't really loud or really even annoying. I just figured it might be a symptom of improper carb tuning or something and didn't want to keep running it if it is causing damage or something.

No problem, just keep in mind that you allowed the engine to breathe better by doing the mod's that you did. So you deffinitely leaned it out a bit, probably not enough to lean it to the danger zone. But it's always wise to check your spark plug anyway when you do any performance related modifications just to be cautious. Always remember small changes in these little engines make a world of difference most of the time...