Need Help!!!!

[kennyo1]

I have a 2005 -400ex, Curtis sparks X4 pipe 155 main, 38 pilot. It has run with these jets for 2 years so Jetting should not be an issue. I recently installed a Sparks +6 key. Started it in nuetral seemed to rev good, idle good, so I thought all was OK. It has been sitting a while since I started it. Stated the other day and it ran like crap. Today I dumped the tank, totally dissassembled the carb. The pilot jet did have dirt in it. I used carb cleaner and compressed air to clean all orifices and jets. I filled with fresh 93 octane. The F/A screw is out 3 turns.

I also cleaned the plug with a small wire brush.It did not seem that dirty.

I just stared it and there is no difference. It is hard to start, intermittendly pops through the exhaust while idling and seeems to break up when I rev it up.

I tried closing the choke to see it made a difference- no difference.

Could I have messed up something in the carb? Lost a small part. Any ideas??? Could the recently installed key be a problem?

Any help would be greatll appreciated.

[JOHNDOE83]

If all that usually checks out good, the next step is the coil. try to switch it with a friends or one you can find for cheap and see if it works.

look up the online manual and see if you have all the carb parts before buying a coil though...lol.

[kennyo1]

Will that cause it to run like crap? Is there a way to test it? Can it be tested with an OHM meter?

[JOHNDOE83]

I think it can be tested wit a average volt meter, a guy I used to hang out with re wired a coil from a ninja to fit a suzuki 250 atv using a cheap volt meter.

You could try taking off the front plastics, ride around and try to wiggle the coil a lil bit and see if it messin up when you do it, or look for a loose coil ground wire. try to let it idle and wiggle the plug wire also.

[kennyo1]

Will a coil or wire problem cause it to pop through the exhaust while idling?

[JOHNDOE83]

usually a lean pilot jet will make it pop, but I would guess that a bad coil or plug wire could make it backfire if it were messing up the spark.

Show some video of it if possible....lol.... That would really help.

[kennyo1]

I don't have a video recorder available. It pops through the exhaust while idling. it breaks up when revving. Could the A/F screw be out of adjustment? I have it three turns out.

[TRXRacer1]

Jetting won't really cause popping just idling. First thoughts are contaminates from a gas can or electrical. Does it do this with a cold engine too or just after warmed up?

[kennyo1]

Pops cold and hot, but haven't ridden it. Just tries extrwmws on the FA screw1 1/2, 3 ,4 and 5 turns out, doesn't make much of a difference.

[JOHNDOE83]

In your sig it says rev box for one of your mods, if you still have your stock rev box, try putting the stock one back on and see if it helps, sometimes the aftermarket rev box changes timing a lil bit, with that along with the key, you could have to much timing?

[kennyo1]

THANK YOU JEDI MASTER!!! I just put the stock rev box on and it started up, idled smooth and revved just fine.
I would have never thought that would be the fix.

Is a rev box a bad idea with the sparks key????

If you are ever around New Orleans I owe you lunch. Thanks a bunch!!!!!

The kids will be happy, now I can take them riding.. :) :) :)

[JOHNDOE83]

Not that its a bad idea, just that some after market rev boxes have an increased rev limiter, that along with a +6 degree key could have made the timing to advanced....in this case it did.

All the carb trouble shooting was done and fine, that only leaves the ignition system, Once I read your sig and saw rev box and a +6 key, I knew that had to be it, you had all the symptoms of a lean pilot at first, Then I read the sig and saw you had the box then installed the key, then had the issue.

If that wasnt it and the coil wasnt it, I would've asked if you put the key in backwards...lol.

Glad we solved the problem...lol.

[kennyo1]

The rev box was a Procon part # PE-C-AH400-B. It was installed by the previous owner. The funny thing is that when I first installed the key, I started it and it idled, and revved fine. Because it sat for a while I thought it must be the carb.