200x Help!

[jkg2003]

I'm begging for help!

84 200x
Air box lid delete
Uni filter
Header
Richter exhaust

Ok my issue is while cruising all gears it back fires/misses. Full throttle runs fine, but once it's hot, won't idle unless idle screw is all the way in. It is extremely rich and wet spark plug with the factory 108/40 jets. Air/fuel screw 2 1/4 turns, needle 4th clip. I've recently dropped to a 102 and no change. It should be lean at 108 with the air lid and exhaust not rich. I've checked my intake, only thing I can think of is the timings off, not sure if that will cause my issues!

Please help, I'm about to give up!

[jkg2003]

Anyone????

[Jmoozy27]

Sounds like weak spark or clogged air filter

[Dirtcrasher]

I've never seen timing change aside from the assembler screwing it up.

108 main jet seems quite a bit lean if the air box lid is off. Isn't stock around 112 or so?? Lid off would mean an even larger jet....

2.25 turns out means you can jump up the pilot one size.

Make sure the exhaust has no leaks.

Make sure the air screw is complete (screw/spring/washer and last, the O-ring)....

[jkg2003]

That's why im confused, it's rich even with all the other items.http://uploads.tapatalk-cdn.com/20160501/e1b54b739634b2ba40602042a9e57263.jpg

[Scootertrash]

have you given the carb a thorough cleaning lately?

[jkg2003]

Not a dirty carb, haven't rebuilt it, the picture above is with a 102/40 jet

[jkg2003]

No way it should be that rich

[Jmoozy27]

Weak spark

[jkg2003]

Not a spark issue

[Jmoozy27]

Not a spark issue

Just because it sparks when you turn it over doesn't mean that it has good spark. It needs a fat blue arc.

Also check for a clogged exhaust. How old is the filter? Is it oiled?

[jkg2003]

I understand, but there isn't a spark issue, exhaust not the issue. The filter is oiled, will put a new moose filter on it tomorrow with the needle.

[fieldy]

Do you know the compression? Have you checked for air leak around intake? Is this the factory carb?

[jkg2003]

Air leak causes a lean situation, but yes I checked the intake. Factory carb. I think a worn needle seems plausible, maybe a clean filter...

[Jmoozy27]

Air leak causes a lean situation, but yes I checked the intake. Factory carb. I think a worn needle seems plausible, maybe a clean filter...

What part of Texas are you?

[fieldy]

I havent followed these 200x threads latley so to me it sounds like a dirt in the carb with the backfire situation. Not sure what else causes backfiring on deceleration. A compression check may save you time. Did it ever run right for you? Hope you get it going.

[RUNMEDOWN]

sounds like a dirt in the carb with the backfire situation. Not sure what else causes backfiring on deceleration.
Sounds silly but a broken/weak choke valve spring did this to me for a bit on my 110, it looks open when sitting but will suck itself shut and run rich until you let off the gas. I was at wits end with it until I read the same advice on this site somewhere. Use a pull tie to lock the arm open and see if that helps.

[jkg2003]

It back fires during the cruising not deceleration. Choke is open, carb is clean. The only time it ran better is filter less.

[jkg2003]

I'm near Dallas! McKinney actually!

It's going to be something out of the norm, I'm very mechanically inclined and have tried all the normal ideas. I didn't come to y'all before, I've tried almost everything already.

[yaegerb]

how old is that sparkplug?

Only two reasons for your backfiring on acceleration.

1. Air to fuel mixture incorrect
2. Electrical issues (timing and/or not enough spark)

Backfire on deceleration, that's a different story.

[jkg2003]

Not back firing on acceleration either, only constant throttle, cruise control! I'll change the needle then adjust my air/fuel mixture again, but with the exhaust and air box, something is bad or out of place. Hoping the needle or seat is bad, that way I know it was something beside normal tuning. Spark plug has 10-15 mins riding time

[jkg2003]

I'll check timing, I also think that may be a cause!

[yaegerb]

Not back firing on acceleration either, only constant throttle, cruise control! I'll change the needle then adjust my air/fuel mixture again, but with the exhaust and air box, something is bad or out of place. Hoping the needle or seat is bad, that way I know it was something beside normal tuning. Spark plug has 10-15 mins riding time


uh, constant throttle is acceleration....you have to keep momentum somehow.

[oscarmayer]

Your dumping fuel into the engine. Are you sure the jet is correct? I know I have resized jets track side for my son's racing quad and made noted on the box. Try getting s known sided jet and put that in there. Also is the choke working properly. If choke is letting extra fuel by it will also cause this.

Only other thing,
Are you blowing smoke when it runs? If you are it could be some oil too.


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[YTZ drew]

What about float level, has it been checked? Put a piece of clear tubing on the bowl drain nipple, route it upwards, and open the bowl drain screw. The fuel should come up in the tube, and end up about level or a little bit lower than the float bowl flange.

[loganm]

If it's rich have you tried just going down in main jet size? Do the obvious things first and note what happens before you get into any nut job theories.

[tripledog]

I understand, but there isn't a spark issue, exhaust not the issue. The filter is oiled, will put a new moose filter on it tomorrow with the needle.

The moose filters are great. They will also help to keep elk out of your engine.

[jkg2003]

I am at a 102 main jet, tried that first, float level hasn't been checked, is there a way to adjust the plastic floats, only reason I didn't check it. No considerable smoke, only a slight puff at start up.

[oscarmayer]

No adjusting plastic floats. The needle may be bad.


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[jkg2003]

The moose filters are great. They will also help to keep elk out of your engine.

I heard they will keep caribou out as well!

[loganm]

I am at a 102 main jet, tried that first, float level hasn't been checked, is there a way to adjust the plastic floats, only reason I didn't check it. No considerable smoke, only a slight puff at start up.

I'm kinda drunk but, just run through the basics. Compression test, new spark plug, etc. Post up results.