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Cheap and easy Flapper mod

8K views 23 replies 13 participants last post by  robsp2 
#1 ·
Hey guys, I did the flapper mod and wasn't able to spend the cash to purchase one of those sharper looking covers that bolts onto the snorkel so I went to Lowes and for $1.50 picked this cover up and put it on. Let me know what you think.

Sorry if the picture isn't very good. But you can get them in Chrome or black.

They are crazy light and sit almost flush on the housing.
 

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#3 ·
It's a Hole Plug. Size is 1 3/8. I found it on the nuts and bolts aisle. The part # is 139432. All I did was press all the tabs done except for two the were directly across from each other and I kind of bent those out just a little. Than I worked the two tabs into the slots that the previous tabs would be inserted into and turned it. I figured if it stays it looks great and if it happens to fly off I'm out a $1.50. But it feels pretty snug in there.

Here's a picture of the plug.
 

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#7 ·
Haha, I like the duc tape but I do believe that may set you back more than $1.50 if you have to buy a roll. But well done.
 
#11 ·
Air tight?

Shouldn't this be air-tight?
I would think this contraption cap at high speed while you shut the throttle off too much pressure may send it up to your face.

Maybe if you can find an o-ring for it to seat on and then drill and attach the valve's spring/blade on to secure it?

Maybe even stick a little digital clock on it and cover the bolt head :)
 
#12 ·
Maybe you can dab some super glue underneath it but last night I was riding at speeds over a 100 and that little guy stayed put.



Has anyone else tried this? I'm just curious. I love it but I may be a little bias.
 
#13 ·
After all this talk, how can I tell if the previous owner did this ? The cover on my bikes looks a bit suspect to me...is there a way without tearing down the bike to find out ? Would pictures help ?
 
#15 ·
ZeroGara got a good point. i think of the fact that you're not re-using the factory spring thingy that holds the cap securly to the airbox. it's gotta be a lot stronger than the two tabs you're relying on to hold it in place under an extreme condition. not critisizing, just saying...
 
#18 ·
Thanks Sub / Rob and Jon, I will take a good look this weekend.
 
#19 ·
I think the ram-air effect is slightly higher pressure at high speed, just enough so you do not have lack of air in the airbox and even then I think at top end max speed WFO throttle the pressure is less than 1atm. When you shut the throttle off at high speed air accumulates and pressure builds at about 1.1-1.15atm = 1.5-2psi, not much. Without the ram air it may drop down to 0.7atm.
So any leak at that point where the snorkel is will disable the ram-air. It doesn't have to pop-off to leak.
 
#21 ·
Hey everyone, I just wanted to follow-up on this old post of mine. There were some concerns about the cap not being strong enough and flying off. I have had this installed for about a month now and Mindy Sue (That's my RC) Is my daily driver. I have gone out and raced, lot's of highway and in-town riding, and some long distance rides and those two little tabs haven't given at all. I just wanted to say that for those who were interested in this but worried about that, shouldn't have a problem.
 
#22 ·
Interesting physics problem.
If you can attach a hook at the center of the cap and pull on it with a pull scale and record at what force the cap loses the seal, that would be like a pressure regulator valve.
If the area of the cap is say 3squarte inches and the force is 24lb, then the pressure is 8psi. If it is 60 lb it is 20psi (1.4bar) that's good turbo boost :)

Alternatively you can find a small pressure gauge, drill and plug in the sensor on the cap and watch the pressure rise real time.

OK, OK, enough! :)
 
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