I Give Up

[chinaguy]

I give up. I don't know what to check anymore.

About two weeks ago I got the bright idea of fooling around with the carb, just to see if could get it to run even better than it was. I should have left my hands off. Once I moved the needle clip the bike will idle, but at about 3,000 rpms it breaks up and backfires, like an extremely lean condition. I moved the clip to a couple of of different spots and nothing helps. I tried turning the fuel mixture screw all the way in and then trying to adjust it from about 2 1/2 turns out. I checked the plug, checked the gap, tried a new plug. The plug is a little whitish, like it was running too lean. Nothing helps. I don't know anything else to try except take it to the dealer and see if he can fix it. The whole thing p****s me off, because it was running good, and now I have to load it up and take about 25 miles in the back of my truck.

I should add that I took the carb off and cleaned it and the main jet.

Anybody know anything else I could try?

[IronFist]

Check your intake and exhaust manifolds for leaks?

Maybe it's not related to the mod at all. Mice in the airbox?

[alonzo]

yep, if you did not tighten the carb down to the manifold good enugh it will cause a lean condition, and the leak gets worse as the vacum/engine speed increases.

If the manifold is straight makesure that you carb didn't get fouled up when you had it apart.

[forchetto]

Have you removed or modded the airbox?. I don't know the bike details but, if it has a CV type carb, messing with the airbox can end in tears. Ordinary piston-type carbs are not so fussy, but is still best to do your testing with the original airbox in position.

[chinaguy]

Sorry. I should have mentioned that it is a slide needle type carb. It doesn't makes any difference if I run the engine with or without the air filter.

[alonzo]

did you take the float bowl off?

Isn't 3,000 where the main jet takes over for the idle system? you might just pull the carb back off and take you float bowl off and pull the mainjet and clean it up with a can of carb cleaner.

[Jim]

I had water in my gas, it would idle just fine, but if I gave it throttle it would die out, I don't think that's your issue, just putting it out there...

[VinceDrake]

Just re-reading the post, I was kinda thinking, maybe somewhere in the process of the carb-work, maybe the fuel supply line got kinked or collapsed? Might be a good idea to trace the supply line, and do a quick flow test....

--Vince

[red2003]

Yup, for sure you got main jet issues. There must be something in there. Take a break and breathe. You will probably have to pull the carb and clean it again. Take ALL the jets right out (un screw) and spray some carb cleaner into each port and make sure it flows out somewhere else in the carb body. Use some compressed air to make certain nothing is blocking the jets. Like stated above, make sure the bolts are all tight, and the o-ring seals are all in good shape so you have no air leaks. Also, make sure you have the choke cable attached correctly so the choke isn't partially on when you think you got it shut off. Make sure you got the needle back in the slide correctly. I'd try one position up from the pointy end and 2 turns out on the fuel screw. You CAN AND WILL figure this out. It's something simple, I am sure. You just gotta plug away at it. It'll come around!

[tigertamer]

Another thing to check is the material of your fuel line...Mine was shipped with vacuum hose instead of fuel line 8O

Also, if you're in doubt, you can change the fuel in the tank, just in case you got a bad dose :idea:

Good luck,
Tigertamer

[warrior91]

Another thing to check is the material of your fuel line...Mine was shipped with vacuum hose instead of fuel line 8O

Also, if you're in doubt, you can change the fuel in the tank, just in case you got a bad dose :idea:

Good luck,
Tigertamer

Indeed ,mine as well. It took about 2 weeks of fuel running through before the rubber started splitting/cracking and tearing....

[chinaguy]

I took the carb off again today (which is really a PITA) and I cleaned out the jets again. I buttoned everything back up and just took a spin on it, and it's about 80%. It still sputters a little under hard acceleration. I might be able to adjust the fuel mixture screw a little more to get it just right. I'm thinking it was water (or something) in the gas, or dirt in the main jet. The baffles in the tail pipe have come loose again- I already had them welded once - so I will probably get that fixed before I really fine tune the carb.

Thanks to IronFist, alonzo, forchetto, Jim, VinceDrake, red2003, warrior91, and tigertamer for the encouragement and advice!!

[IronFist]

You sir are very welcome! :D
I'm glad to hear it lad. More than I can explain. As my motorcyclye guru says. "I work for appreciation."

I'm sure alonzo, forchetto, Jim, VinceDrake, re2003, warrior91, and tigertamer will say the same.

Red too. I'd vote for red :wink:

The other 20% is reachable. At 100%, the bike may surprize you. 8O

[Jim]

Glad to hear it :), the baffles in my gy5 came loose too, but after re welding them it was fine... I considered gutting it and putting it back together empty, but it was fine after the initial repair so I didn't bother... I figured it would wind up with a similar effect as others have achieved by drilling some holes in the end cap, but I don't know for sure...

[VinceDrake]

I'm glad to hear you're mobile again, sir!

If nothing else, by the time you're back to 100% you'll be a carb master! (and with these machines, that's probably a very good thing!)

In all seriousness though, it would probably be wise to change out the fuel hoses to something competant. I can't speak for your specific model, but everything I own, and have worked on has the nastiest, cheesi-est crap on them for fuel lines. May a fuel filter would be a good idea too.

But back to the subject at hand-- You're getting there. Patience and perseverence wins every time, and the more you can handle yourself, the lesss you are at the Mercy of the bike shops. At least locally, I've found bike and boat shops really have no idea how carbs work. (Ask me about the local Mercury Marine dealer sometime....)

Best Wishes
--Vince

[chinaguy]

Vince,

Thanks for the tip on the fuel filter. I actually was thinking of doing that anyway. The line from the tank to the carb is short, I'm guessing about 10-12", but I think I can squeeze a small filter in there. It would probably prevent trouble down the line.

Jim,

I had the baffles rewelded a couple of weeks ago, but some of the bead broke. This might give me a good excuse to get a MIG welder, haha.

[tigertamer]

Pizzarider may want to borrow that MIG when your'e done :lol:

TT

[chinaguy]

Well, as usual, I spoke too soon.

I thought I had everything fixed when I took the carb out and cleaned everything (for the 2nd time) yesterday. I went for a little ride last night and there was a little hesitation when applying throttle, but I thought I could adjust the fuel mix screw to smooth it out. Nope. This morning, I started it up and it breaks up around 3,000 rpm again, all the time.

Now, I'm starting to suspect crud in the gas tank. I guess I'll have to drain it out into something and fill up with fresh fuel. What am I supposed to do with the fuel I drain out? And, another question: I've using regular unleaded in both the bike and the lawn mower. Should I be using mid-grade unleaded?

[AZ200cc]

Regular unleaded is fine, May snag a can of seafoam and use that for a tank or two. An inline filter will help a bunch if that tank is nasty.

[tigertamer]

I only use 93 octane in mine.

How much fuel do you have, you may be able to salvage some for your Lawnmower! You can put it in an approved container, and pour a jar at a time to examine the fuel for water and particulates.

The water will accumulate on the bottom, so you just ladle-out the fuel. The fuel can then be filtered with a cloth. this can be used in your small engines.

Just remember safety when you have unsealed fuel containers!

Keep pluggin,
Tigertamer

[IronFist]

Regular :wink:

You might try a rejet if too lean. Your fuel mixture screw is for idle. :wink:

[theENIGMATIC]

Sounds like you might have screwed something the wrong way as it all worked until you tried the mod???
Ive done that to my bike several times....I would inspect everything with the carb and try to put it back to how it was if possible.good luck! :?

[VinceDrake]

Just a warning-- I use the seafoam treatment pretty often on older bikes, BUT! Put in a Fuel filter FIRST Not only does it dislodge crap from carbys, it dislodges crap from the fuel tank too!

Just for my curiosity, what does the plug look like when it comes out?

--Vince

[chinaguy]

The plug looks tanish-whitish, like you would expect a plug would look like from an engine running lean.

I'm definitely going to get a fuel filter, and I'm gonna drain the carb and the tank. I thought also that I might have put something back wrong, but I can't see anything that doesn't look right. I hate it when stuff works off and on; it makes it really hard to pin down what's going on. I'll keep slugging away and keep you guys posted. Maybe we can all learn something - probably how NOT to do something.

[VinceDrake]

You knwo, I was just thinking about it and a couple of members have had problems with the vent in the fuel cap plugging up, so as you draw fuel out of the tank, it builds a vaccuum, and starves the Carb to death.

Easiest way to check, take the bike for a rip with the fuel cap unlocked (Try not to set it on fire...)

Phase 2-- Check for fuel flow at the carburetor. Remove fuel line from carby, put in suitable container, and open petcock. Should come out in a solid stream, not dribble. (insert phallic comment here...)

I figure we'll prove the basics, and move deeper from there...

--Vince

[alonzo]

keep in mind this is in the morning "when fuel is cold" so if there is a good "ish" seal on the cap it migh be a vaccum problem.

Did you flush the entire main jet circuit with carb cleaner? you Need to make sure to take off the main jet and spray carb cleaner directly into the port. any slight amount of sludge will foul up this jet make sure it is 110% clean.

[chinaguy]

Thanks guys. Three great suggestions.

1. Check the fuel cap for proper venting (try the bike with cap off).

2. Clean the carb jets with carb cleaner ( I didn't so that).

3. Check the fuel flow from the tank to the carb.

I'll try all three of these tomorrow and report back.

[duck]

Oke, just for your own sanity, check all the wiring connections, make sure nothing is melting against the exhaust (like under the seat), and that none of the wires have pulled out of the wiring blocks next to the carb.

I know...it happened when you did the carb....but you had to get interference out of the way to work on that carb and 'stuff happens'.

Next, check for a carb to intake leak, with a running engine you can point a small propane torch (with flame off!) at the carb to manifold connection...if engine speed jumps up, you have a leak. Do this safely, if you're not sure how to, don't do it, propane goes boom.

[IronFist]

Duck:"check for a carb to intake leak, with a running engine you can point a small propane torch (with flame off!) at the carb to manifold connection...if engine speed jumps up, you have a leak. Do this safely, if you're not sure how to, don't do it, propane goes boom."

Or you could try 10W30. It temporarally seals the hole. If the bike runs better for 30 seconds, because you sprayed 10W30, then you have a leak.

The bonus with 10w30 is that when you wipe it off, you clean your bike, also no "BOOM" 8O .

[theENIGMATIC]

Good thinking, I noticed the wire tube thing that connects to the spark plug was burning on my exhaust, lucky I caught it and zip tied it out of the way or it wouldnt have taken too long for it to burn in half?

[VinceDrake]

If you don't like the messiness, Carb and Choke cleaner works excellent too. Engines like the propellant, and they speed up nicely when they get a little C&C instead of raw air.

Thinking about it further, Mr. Duck has a good point, intermittent electrical short *will* cause igniton break up on these machines. Good idea to check for grounded/melted/poopy wires, while you're in there anyways.

--Vince

[metcalfguitars]

Check the boot on the spark plug. I changed my plug and inadvertently let the boot slide up the wire, away from the plug and it would start cutting out about mid-speed (no tach). I was grounded a few days until I discovered it!
Tim

[chinaguy]

Metcalfguitars sounds very familiar; do you belong to Harmony Central's acoustic guitar site?

[metcalfguitars]

No, but several of my guitars have been reviewed there.
Tim

metcalfguitars.com

[chinaguy]

Well, it's good to know you because you're interested in China bikes, and the fact that you are interested in guitars, as I am, is also nice!

[jshellito]

Well, as usual, I spoke too soon.

I thought I had everything fixed when I took the carb out and cleaned everything (for the 2nd time) yesterday. I went for a little ride last night and there was a little hesitation when applying throttle, but I thought I could adjust the fuel mix screw to smooth it out. Nope. This morning, I started it up and it breaks up around 3,000 rpm again, all the time.

Now, I'm starting to suspect crud in the gas tank. I guess I'll have to drain it out into something and fill up with fresh fuel. What am I supposed to do with the fuel I drain out? And, another question: I've using regular unleaded in both the bike and the lawn mower. Should I be using mid-grade unleaded?

I have to run 92 min, I tried regular and the bike ran like crap.
Whats the owners book call for?

[chinaguy]

I finally found out that a loose ignition wire was causing the stumbling at about 4,000 rpm. The wiring plug was ok, but one of the wires was loose.

As far as fuel, my owner's manual says "We recommend that the gasoline brand is RQ-90 or over RQ-90." I don't know what that means. I think that regular unleaded is 89 octane, so maybe that's what they are referring to. It stands to reason that these engines would probably run a little better on a higher octane. It might not be a bad idea to use mid price unleaded. I'm not sure; is mid price like 92 octane?

[jshellito]

I finally found out that a loose ignition wire was causing the stumbling at about 4,000 rpm. The wiring plug was ok, but one of the wires was loose.

As far as fuel, my owner's manual says "We recommend that the gasoline brand is RQ-90 or over RQ-90." I don't know what that means. I think that regular unleaded is 89 octane, so maybe that's what they are referring to. It stands to reason that these engines would probably run a little better on a higher octane. It might not be a bad idea to use mid price unleaded. I'm not sure; is mid price like 92 octane?

87 is reg, 89is plus, 91 and above is super.
Try the super i'm pretty sure thats what you should be running.

[chinaguy]

That's good to know. I've been running 87 octane (regular) in mine. I'm gonna try a higher grade.

[jshellito]

Considering the tank size and the mileage we get, It don't hurt are wallet to much for better gas. I'm just glad my car don't call for super that would REALLY hurt.