Poppin'

[pdxguy]

Hey Guys,

We have a local indoor track here and I finally decided to go check them out. Didn't ride, but went down to watch the action.

While we were there, they had some bikes (not quads) running around and we noticed that two of them were poppin' pretty bad, like a back fire. Not sure what size bikes they were, but one was a Kawasaki (four stroke) and the other was a Suzuki (2 stroke). It seemed to pop when they got on it - going through the whoops and sometimes when throttling up for a jump.

This got me thinking - what makes it pop? Seems like I have read here that running lean will do it. Are there other things that can cause this? I've also noticed that occasionally on my quad if I'm running around, it will pop a little (not real loud like the bikes where) when I let up off the throttle.

-pdxguy

Oh the site for the local track is: http://www.hindsightmx.com

 

[yamarider]

they were probably running lean. I notice the same thing at races, there seems to be a lot of popping, but usually there's only one or 2 bikes or quads that do it out of the entire pack, and they're usually towards the tail end of the field by the end of the race. Before I rejetted with my HMF my warrior was popping loud like that a lot and shooting 8 inch blue flames out the exhaust when I ran it hard.

 

[pdxguy]

My dad was with me and he mentioned that he saw flames. I couldn't notice them, and any flashes of light were hard to determine whether it was a reflection or a spark/flame.

Where you running lean by just running a pipe or had you changed the intake/filter as well?

 

[yamarider]

I had a UNI 2 stage filter in it too, but that doesn't make much of a difference for jetting. My flames weren't real noticable, I didn't even think about it until I watched my cousin ride it in the dark and saw that the header was glowing and there was "fire in the hole"

 

[pdxguy]

Okay, I'm running an aftermarket pipe for now... but I haven't changed anything for intake yet. I rode it really hard on New Years - most of the night and didn't notice any glowing so that's good. I know I need to do a plug chop at some point, and I want to go K&N as well, but it'll be atleast a few months before I make the change.

 

[DeathShadow]

Sometimes a high performance bike will pop on the deexcel just because and its normal.

 

[pdxguy]

Hey Death,

Is this is reference to the bikes I was watching or my own? I guess I don't really consider a stock warrior a high performance bike, but mine seems to pop occasionally on deexcel. However, the bikes at the track seemed to do so when pushing them, revving high for jumps and running through the whoops (granted this seems to be a combo of sorts between revs and deexcels)

-pdxguy

 

[DeathShadow]

Hey Death,

Is this is reference to the bikes I was watching or my own? I guess I don't really consider a stock warrior a high performance bike, but mine seems to pop occasionally on deexcel. However, the bikes at the track seemed to do so when pushing them, revving high for jumps and running through the whoops (granted this seems to be a combo of sorts between revs and deexcels)

-pdxguy

Ive found that many bikes with motor mods or high performance add ons do this and the jetting is perfectly fine. Mine use to pop occasion during deexcel and the jetting was perfectly fine - I metered the entire thing and the mixture was well with in acceptable at all ranges.