maiden voyage more like old hag scuffle

Discussion in '2-Stroke Engines' started by wrightmor, Jan 1, 2011.

  1. wrightmor

    wrightmor Member

    Apologies in advance if I am violating or duplicating. I have spent time searching the forums and can't find what I need.

    Today I finished the install of my Grubee 80/66 cc with the high performance carb. The test drive was atrocious. Skipping, sputtering, and dying out. Muffler was smoking when I got back after 10 minute ride.

    The carb is not like the one I had on old motor. There is no primer to press and I see no choke to pull up or push down. There is an extra cable (besides the throttle) coming from carb to handlebar. I am assuming this to be choke?? The instructions coming with these kits leave a lot to be desired. I did read one very detailed post concerning working with carbs and adjusting lean/rich position of the "pac-man" washer. But don't want to make matters worse if that's not it. Total green at mechanics. You think I should get into that, or does it sound like something else.

    The throttle came already attached to the carb and the [choke?]. I did reset the screw on the carb backing off 3 1/2 turns as the instructions said. Didn't seem to help.

    Brand new motor. SHouldn't be this much trouble. any help would be appreciated.

  2. GearNut

    GearNut Active Member

    Brand new motors should not be this much trouble, eh? You are new to the cheap Chinese engine scene arn't you! :)
    Don't worry though, it is fun to learn about them if you have the desire to do so.
    Most folks just replace that particular troublesome carb with the older version NT carb. This tends to solve all the problems with the new kit carbs. I have yet to see a good tuning guide for the newer carbs.

    As for the second cable coming out of the top of the carb, it controls an enrichner circuit. It adds extra fuel to the intake for starting assist but does it differently than a choke plate like the old NT carbs use.

    Try starting from the beginning with a plug chop to determine if you are too lean or too rich. I am betting that you are too rich but I could be all wrong.
  3. wrightmor

    wrightmor Member

    Sorry, "plug chop"??? Told u I was green. and Do you use the enrichner like a choke?
  4. GearNut

    GearNut Active Member

    Plug chop:
    1. Run engine for 1/2 mile or so at the speed in which it is acting up. Take note of the throttle position too. While at this engine speed pull in the clutch and hold down the kill button to simultaneously stop the engine and disconnect it from the drive line. Whatever you do, do not let the engine idle or run at all after doing this or else you will contaminate the spark plug color.
    2. You absolutely MUST let the engine cool down completely before removing the spark plug or you risk pulling the threads out of the cylinder head when you un-screw the spark plug.
    3. Remove the spark plug and take note of it's color at the sparking end. It should be a leather brown to a chocolate brown color. Chocolate brown being a more desirable color.
    If it is white then the carburetor is set too lean. If it is black then the carburetor is set too rich. If it is wet looking and black then the carburetor is set very much too rich.

    Also note that a malfunctioning enrichner will cause a too rich condition too, but let's do one thing at a time here....
    Last edited: Jan 1, 2011
  5. GearNut

    GearNut Active Member

    Oh yeah, yes the enrichner works just like a choke, it just goes about performing it differently.
  6. Dave C

    Dave C Member

    The instructions also don't show something: the plastic tube from the bottom of the carb goes to the barbed vent tube up next to the two control cables. To help prevent other trouble it's a good idea to add rubber tubing to the other two vents. Tie them with zipties so the openings are down, 5-6" of tubing will do. I wasn't too happy with the way they have to hook the cable up to the control. I'm working on a better setup. Might have to go to the cycle salvage place to get a handle there.

    But, yah, the choke setup needs to be hooked up to work right. At least for me it only has to run 10-20 seconds and I have it off. It's really nice not to have to reach down or stop to turn off the choke:cool:
  7. wrightmor

    wrightmor Member

    Great news, guys. Gearnut, I was going to put a fresh plug in motor so I could have a clear pix of the problem on a previously unsmudged plug. You probably already guessed it. No skip, no sputter, just smooth, clean ride. Still have to work with idle speed. I have great idle speed for a while and then the whole motor wants to die out until I use the enricher, then motor is back to normal as well as smooth ride but I lose my idle. That problem I can live with. I probably shouldn't have messed with the screw setting at the carb. When I find I do have an idle again I'll be sure and have my screw driver and try to adjust it. when idle is "good" the bike pulls itself at about 11-12 mph.

    Should have changed plug before I bothered with post. The non-working plug was the one that was already in motor when I received it. The new working plug is an "extra" that was packaged with the other loose parts.

    Thanks so much for your input. Wow, I'm on the road again. I love my bike. Hope it will last me. the other played out after about 2 years. Had I been mechanically inclined I might could have fixed it but I usually make things worse. and to pay for repair, I figure, why not go ahead and get a new and improved.

    Dave, thanks to you too. I'm still trying to figure that loose end air hose you were talking about. I have one. I figured it was supposed to be that way for ventilation or something. Honestly the instructions were useless. Thank God, all I had to do was rip out the old motor and put the new one back in. I was even able to use the same mounting holes on bike frame.
  8. motorpsycho

    motorpsycho Active Member

    If your engine is pulling you along at 11-12 mph without you touching the throttle, your idle is set way too high.
    You should be able to start the engine, pull in the clutch and let the engine idle.
    It should be (guessing) around 200-300 rpms "putt-putt-putt..." Your engine should sound like a weedeater when it's at an idle. (just "putt-putt-putting...")
    Get it running and take off. Once you get to a decent speed, pull in the clutch and the engine should return to a low "putt-putt-putt.." idle.

    You say "I have great idle speed for a while and then the whole motor wants to die out until I use the enricher, then motor is back to normal as well as smooth ride but I lose my idle. That problem I can live with."
    This is not how these engines are supposed to run! Yeah they are cheap little engines, but with proper tuning and set up, you can make them run excellent.
    This tells me that you are not caring that the engine runs at it's best. This would not be an issue if you fully understood how the engine is supposed to run and idle, and how to tune the carb.
    If you can live with this problem, I wonder how many other problems you have that you don't even know about.
    Last edited: Jan 2, 2011
  9. wrightmor

    wrightmor Member

    can live with

    What I meant was this problem (idle speed) seems a lot more fixable (turning the set screw til I get it right). Plus I was ecstatic that I got the ruff ride out of the motor from my initial ride. I know I have to make some adjustments and I am not content to ride without making them. It's just that I can see beginning improvements over what I had just yesterday.
    Granted, I'm not a mechanic (yet) but I know I can learn some of the more basic ins and outs of these motors and have a durable ride.
    Thanks, Psycho for your input. I value any thread of help I can get at this time, since I am relatively new at this.
  10. wrightmor

    wrightmor Member

    only complaint now is idle speed. there are two adjusting screws on carb. one is at an angle into the carb on the left toward the back of carb. the other is straight into side of carb and more toward center. The latter seemed to have more effect on idle, but still not able to adjust and keep idle speed. bike runs good but will threaten to keel out after a while until I pull the enrichment lever. I leave this lever out til bike runs normally then shut it down again for a few blocks til it happens again. I think both adjustment screws now are out of whack. The instruction manual I have is for the old carb not this new and improved[?]. so not much help. doesn't even refer to the second adjustment screw the one running straight into carb at center.
  11. motorpsycho

    motorpsycho Active Member

    Just a wild guess, but the screw that runs straight into the side/center of the carb is probably the idle adjustment screw. The easy way to find out is to remove the top cap of the carb, and pull the slide out. You should be able to look down into the carb from the top to see which one is the idle adjustment screw. The idle adjustment screw will be visible because it is tapered, makes contact with the slide, and it moves the slide up & down depending on which way you turn it.

    I'm guessing that the other screw is an air/fuel mixture screw and it will affect the idle even tho it is not an idle adjustment screw. When you lean out the mixture (more air than fuel) the idle will go up without touching the idle adjustment screw. When you richen the mixture (more gas than air) the idle will go down without touching the idle adjustment screw.
    When you turn the screw out (loosen it) this should make the mixture leaner.
    When you turn the screw in (tighten it) this should make the mixture richer.
    The trick is to find a happy medium with the air/fuel mixture screw so that the engine will sit there and idle without having to mess with the throttle or anything else, AND so that the engine runs strong and does not 4 stroke or bog under acceleration and at w.o.t.
    It can be tricky to get it set right.
    You want your spark plug to be a nice tan /carmel color, and you want your engine to idle good and run good with no bogging or 2 stroking.
    If you have to keep messing with it you may have an air leak, because normally once you get the air/fuel mixture scew set where it needs to be, and the idle screw set to where it needs to be, you shouldn't have to mess with them any more. Maybe later on down the road you may have to tweak them a little due to wear, gas/oil ratio changes, or outside air temps. Generally, once you find the sweet spot of the 2 screws, any tweaks that need to be made to them should be very minor.

    I have a cns knock-off carb called a wabro (no, not walbro), and it is very similar to the high performance carb with the air/fuel mixture scew, vent tubes and all that. mine works good, but it's jetted a tad too lean. I have been trying to find jets for it and the delorto jets that sick bike parts sells will not fit it.
    So, i know that tuning these carbs can be a nightmare, but it can be done.
    Last edited: Jan 4, 2011
  12. wrightmor

    wrightmor Member

    Great ride now.

    Many thanks, Psycho, for the adjustment info. You were 100 % on the money. Now that I know a little bit more about what I'm doing when I turn those two screws, I have very good idle and the motor is cutting out a lot less if at all. Didn't ride much after I tested idle speed.
    I did notice a couple of oil drops where I had parked bike, but could not find even a trace of oil moisture anywhere on the motor or clutch. Mystery. Not real worried about that - yet. Maybe a fluke.
    Thanks again for advice. You are 200 % more knowledgeable than I. I wouldn't think of rebuilding or tinkering with the guts of this carb (at least not yet). But I do enjoy the ride.
    Last edited: Jan 6, 2011