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Discussion Starter #1
After completing the air box mod and black box delete mod (and running for near a month flawlessly) I'm beginning to get alot of backfiring. Only on heavy WOT accellerating. Not at idle, not on decelleration, but most always when rowing through the gears.

I went back to OE black box and air box (why the hell Honda built the damn thing like that in the first place is still a friggin' mystery to me since the mods are like "WAY COOL") and it still backfires. No change at all.

Some friend of mine asked me to look into changing my FPR screw all the way out (or was it in??). This friend, however, happens to also be a guy who recently blew an engine in his ghettoed out Civic.

Question asked to you is what else could it be if the plugs/wires/rotor/cap are all new and the mods were working fine for some time and then this crap happens..?..

Any suggestions??

Thanks as always and please don't hate on my question. If you truly are a Honda God, then snap the fingers and solve my backfiring problem instead of asking me do "search for it."

Again, thanks!
-Ivan
 

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Backfiring while on the gas or between the gears? Is there any hesitation while its backfireing? Or just noise?
 

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Discussion Starter #3
Power is definitley lost while acclelerating. Not in between gears, more like when I'm running in bewtween 4 and 6K RPM's. There is alot of hesitation as well....

Thanks,
Ivan
 

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check your ignition timing. Make sure the motor is getting fule too.
 

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The first thing that comes to mind is your accelerator pump might have just shat itself on the carbs, maybe its seized, could be also your choke is stuck open, on the other end of the fuel spectrum. Umm.. hm, well, the easiest thing to do right now is soak your carbs down in cleaner and jiggle everything around, that might free up something thats stuck.. But if your worried about your 'mods' being the cause, I'd say almost 100% no.

Try the cleaner first I'd say,, timing is a possibility but usually distributors dont just walk themselves off their settings,, I was also thinking maybe its your vac-advance but probally not, for one you ran without the black box fine for months you said, and I remember disconnecting mine and it didnt have any effect on upper end rpms.
 

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can we say timming
 

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carbs id check the ruber gasket thingys that thos bike carbs are clamped onto.

check you intake manifold for a leak
 

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Discussion Starter #8
hey, you know I was thinking timing today as well when I was driving it on the way to work....

I notice that there are rapid/sporadic backfires with almost no consistency.

It's almost like "da..da..da,da,da,da.....da.da..dadada" when I'm straight "Getting it" but when I'm at idle, its smooth.

(sounds like my kids when they were babies ..."da, da, da," :))

You think that the timing is off??

Should I or would it benefit me to advance or retard it a specific amount with the airbox/vac lines/black box mods that I made or should I run it straight up at Zero degrees?

I have a light and will attempt to time it until I get another repsonse.

Again, thanks alot for the insight y'all.

Take care,
Ivan
 

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He has a smooth idle, but bad top end, its not his timing, but hes now convinced otherwise. Everything hes said are symptoms of leaning out in the top end.
 

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IE fuel delivery or its an intake leak
 

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Discussion Starter #14
Sky_kiD said:
He has a smooth idle, but bad top end, its not his timing, but hes now convinced otherwise. Everything hes said are symptoms of leaning out in the top end.
I checked timing...dead on. I advanced it a couple degrees...no real change...retarded it, same thing. Runs best at 0 degrees in my case.

What can I do about the fuel issue? New electric high volume pump?? Go back to restricting air?? I like the airbox the way that it is and like the change??

I also am noticing that it doesn't start to "act up" until I driven it a few miles or gotten it into the "Normal" temp range. When I first get into it, it runs like a raped ape and doesn't backfire at all.

It's only after I'd say 12 - 15 miles and once it's warmed up.

Does that change any minds or thoughts??

Thanks for the insight all,
Ivan
 

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zomg im shocked you mean your timing was fine! :O

Checklist, or something

-Fuel filters, cheap, probally a good idea to replace them
-Carb cleaner, also couldnt hurt, maybe your choke is stuck open.

Its all downhill from there, checking your fuel pump and things like that, I'd try those two things first.
 

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Isn't backfire caused by gas getting into the exhaust system? One of your carbs maybe letting to much gas through. Try a couple of bottles of carb cleaner in fuel tank. How do your plugs and wires look? Could also be an igniter getting ready to fail or your coil.
 
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