Carburator and other Questions

[KoolBreeze420]

I just got my motor kit installed and I am wondering about a few things first the carburetor in what direction do you turn the idle screw to shut the fuel off so if i need to increase or decrease the idle which direction does what?
The clutch cable has 2 springs one to protect from heat but what is the purpose of the other? I think it goes in between the cable housing and the idle arm. Is it really needed?
The problem I am having is when the spring is installed, I can't get the clutch arm far enough so that when I pull the clutch it disengages. The other issue is the chain how tight is too tight? And does anyone know how to put the chain guard on?

 

[GearNut]

I don't know what type of engine you have.
I will answer your questions with generalized, vague answers because of that fact.
I will assume that you have a China Girl 2 stroke in frame kit.

Turning the idle speed screw inwards raises the idle speed.
Do not confuse this screw with the idle mixture screw. It works differently and for different reasons.

I think that you are actually referring to the clutch cable and not the throttle cable, as judged by your stated issues with your clutch operation.
For clutch help, I refer you to this thread: http://motorbicycling.com/showthread.php?t=22726

I hope that this info helps you.

 

[KoolBreeze420]

Yeah I did mix it up and is now corrected, it's a 66cc skyhawk stock carburetor. The carburetor I have only has an idle screw. I will probable get the better carburetor eventually possible the expansion chamber and the boost bottle in the future and for what I will be using the bike for it will not break my heart I just need it mostly for Dr. appointments may grab a trailer so I can do shopping without having to wait for a taxi. No that thread doesn't answer my question I now how to install the clutch cable. I want to know what the purpose of the spring is and if it really is needed.

 

[2door]

Throw the small spring in the trash or your spare parts box. It serves no useful purpose except to make the clutch harder to pull. Use the larger spring. It is indeed a heat shield.

Forget the 'boost bottle'. You'll simply waste your money. If you want more performance go with the expansion chamber but don't do anything until you have 200 to 300 miles on the engine. They are slow to break in (seat the rings) and adding performance enhancement parts will not help until it is fully broken in.

Installing a smaller rear sprocket will give you an increased top speed but will hinder low speed (take off from dead stop) performance.

Mix your fuel at 24:1 or better still 32:1 and ride the bike. After you've burned two or three gallons then start looking at performance parts but don't be taken in by marketing claims put out there by too many vendors of neck snapping performance parts. Also unless you are mechanically inclined and have some experience with small engines, particularily 2 strokes engines, ignore the advice to start doing modifications to the engine such as porting, piston trimming and balancing crankshafts. Leave the engine alone, at least until it is broken in and you have gained some experience.

Tom

 

[KoolBreeze420]

OK thanks I am not looking for speed or anything like that I just want to get the most out of it.I was thinking of getting the carburetor that puts the choke on the handle bars just to make it easier for me in the colder months should I also wait on that until after I break it in? I am not going to be doing any of that porting and stuff as I said I just want to get the best bang for my buck which means making it run as long as possible and as cheap as possible.
What about the chain how do you know if it's to tight or to lose?
Yes I thought the same about that small spring when I had it installed the clutch was so hard to pull and even when pulled it wasn't far enough to disengage. With the spring not installed the clutch works perfectly this is why I came here to ask about that spring because it made no sense to me the clutch pulls out on its own.
SO the question Why would it need help via that spring? needed an answer so thanks for clearing that up for me.
I am mechanically inclined but not so much with like engine rebuilds I have changed mufflers starters and stuff but mostly I am an electrician. I have rebuilt a few carburetors but all for cars not much experience with 2 stroke engines but im sure I can deal with any problems so long as I can find instructions and diagrams. The instructions I have for this kit is lacking there isn't very much information there and I am sure there is better instructions somewhere I just haven't found them.
You say 35:1 and in the instructions it says break in should be 16:1 then run it 20:1. I have even read that you should break in at 20:1 and run at 50:1 so I am a little confused as to the proper equations for fuel mixture. Currently my first tank is about 18:1. so after 3 tanks I should goto 35:1?

Throw the small spring in the trash or your spare parts box. It serves no useful purpose except to make the clutch harder to pull. Use the larger spring. It is indeed a heat shield.

Forget the 'boost bottle'. You'll simply waste your money. If you want more performance go with the expansion chamber but don't do anything until you have 200 to 300 miles on the engine. They are slow to break in (seat the rings) and adding performance enhancement parts will not help until it is fully broken in.

Installing a smaller rear sprocket will give you an increased top speed but will hinder low speed (take off from dead stop) performance.

Mix your fuel at 24:1 or better still 32:1 and ride the bike. After you've burned two or three gallons then start looking at performance parts but don't be taken in by marketing claims put out there by too many vendors of neck snapping performance parts. Also unless you are mechanically inclined and have some experience with small engines, particularily 2 strokes engines, ignore the advice to start doing modifications to the engine such as porting, piston trimming and balancing crankshafts. Leave the engine alone, at least until it is broken in and you have gained some experience.

Tom

 

[2door]

Yeah, I don't know why they put that small spring in the kits. There is some theory that it helps keep wear off the clutch actuating parts, bucking bar and ball bearing. We say that if those parts are lubricated properly there will be little to know wear when the clutch is engaged.

Chain tension: Shoot for 1/2" to 3/4" slack. Measure it by leaving the clutch engaged and gently rolling the bike forward. When the piston comes up against compression the chain will go slack on the top run. Measure it at the center of the chain between the engine and rear wheel sprockets.

The carburetor with the handlebar control is the notorious CNS carb. Many don't like it because of the difficulty in tuning the beast. Those who have mastered it swear by it. And, it isn't actually a choke. It is a fuel enrichment control. A better option would be the NT carburetor. Simple, easily tuned and will provide all the performance you can expect from a stock, unmodified engine.
If you want a remote operated choke there are some old threads here showing what others have done using an old shifter lever, cable and a spring. Use the search feature and type in 'remote choke'. http://www.google.com/cse?cx=partne...19j12#gsc.tab=0&gsc.q=remote choke&gsc.page=1

You'll get lots of opinions on fuel to oil ratios. Most of us will suggest 24:1 for break in and 32:1 thereafter. Then you have weirdos like me who run 100:1 from break in on.
It is pretty much agreed that the kit recommendation of 16:1 is too much oil and will cause you problems like spark plug fouling and exhaust system plugging. Don't run more than 20:1 at the least. 32:1 is a good ball park ratio after break in.

Good luck

Tom

 

[KoolBreeze420]

OK thanks you have been a huge help. I actually rode it today for a little bit but got a flat gotta pump some air and check for leaks and try ridding a bit more but it ran and seems to be running pretty good. Is there any advantage to changing the stock air filter for something better? Thanks I will look into that remote choke, if there is anything I can do to improve gas mileage or performance that is great, speed is good but not needed as much as reliability and length of use before having to get new parts.
The stock head nuts and bolts should they be changed to something better? I have to grab a torque wrench still but when I do should I look at replacing them nuts and bolts? I have never drove anything with a clutch before and just now when I would stop and try to get moving again, I would stall could you advise me on how to not stall after a stop please.
Thanks so much for all your help.

 

[2door]

Congratulations. That first ride is always a thrill.

The stock air cleaner will perform just fine. There is little to be gained from a stock engine by changing it. Some of the aftermarket air cleaners 'look' better but offer little in the way of performance gains unless you have done some modifications to the engine.

As for performance enhancments, the expansion chamber exhaust systems will provide you with a noticable gain in power but wait until you have 200 to 300 miles on the engine before adding go-fast parts.

Many will tell you to replace all of the hardware (fasteners). In my opinion, based on my years of building and riding these motorized bicycles, it isn't necessary. Buy a good quality torque wrench and use it. I would suggest replacing the chrome acorn nuts on the cylinder head with shouldered hex nuts. It has been reported, and I've seen the acorn nuts bottom out on the stud before full contact with the head which can result in leaking head gaskets. Torque them to 120 to 140 inch pounds and recheck that torque value after a couple of heat/cool cycles.

Most of the problems encountered with the kit hardware is the result of overtightening. Also ignore the advice to "tighten all fasteners after every ride". I agree that you can 'check the tightness' but don't try to get a turn on the wrench or socket. If the torque wrench tells you it's tight, it's tight. Don't turn it anymore. That's where people break studs and cause fastener failure.

We always suggest to pedal up to about 10mph before releasing the clutch to start the engine then when slowing, disengage the clutch if you speed drops below 10mph. Adjust your idle speed so the engine idles just fast enough to keep it running with the clutch disengaged and make sure your clutch cable is adjusted properly so when you squeeze the handlebar lever the clutch is fully disengaged. You can test this by suspending the rear wheel off the floor and spinning the rear wheel with the handlebar clutch lever squeezed. It should spin free with just a little drag from the chain.
Hope some of this helps and answers your questions.
Good luck,have fun and ride safe.

Tom

 

[KoolBreeze420]

My head has hex nut's and not acorn nut's. I got my kit from Motorized Bicycle Canada so maybe they have swapped the acorn nuts already or is something that is now standard maybe. I don't know but since they are hex nuts already no need to change them, just keep them torqued as suggested in the manual correct? Just went for a second ride an all seems fantastic I think I am getting the hang of riding and not stalling a little more practice and I should be all good. Thanks for all your help. I did already change the nuts and bolts in the chain tensioner for stainless steel and also changed the nuts and bolts for the sprocket to stainless steel. I have seen videos and mention that stock ones rust so I wanted to avoid that since I will be doing some winter riding and the salt on the roads here will cause it to rust pretty quickly. Other then that I am going to get some slime and a really good seat that I Can sit on for longer distances and have some fun. Thanks a ton.
There is one thing I wanted to ask it appears that the aftermarket type gas filter I added is causing problems when I turn the gas on the gas goes through the hose into the carburetor out the overflow right on to the ground. I tried turning the filter around then tried it without this is how I determined it has to be the filter causing the problem but I don't understand why I suspect it has to do with some sort of pressure that the gas filter is removing when added to the system. Is there a particular type of filter I need or is there actually another issue?

 

[forest rex]

A fuel filter by itself shouldn't add pressure to make the fuel overflow. Sounds like a float issue in the carb. There is a float much like in a toilet tank that will shut off the fuel supply to the carb when the fuel is above a certain level in the float bowl. The stock float level is pretty high, and if your carburetor is not mounted level it can overflow easily as well as when taking turns and can spill out the carb or its overflow. You can adjust this level by bending the float mounts so it will cut the fuel when it is at a lower level in the float bowl.

 

[2door]

Ditto: What Forest Rex said.
You'll also want to make sure there is no trash in the float valve. Even a tiny piece of crud can keep it open enough to flood the engine and cause overflow. If you have access to compressed air you might want to blow out the carb to clean it paying special attention to the fuel inlet on the carb.

Just to clarify and for your information, the engine doesn't actually "draw fuel" from the tank. It is strickly a gravity flow system. The fuel is drawn, or siphoned by the engine but only up from the float bowl through the main jet. Everything else is controlled by gravity.

Tom

 

[KoolBreeze420]

OK I am am unsure what I should actually do should I strip down the carburetor or do you mean the float that is on the needle perhaps it got stuck open or can you go into more detail or direct me to instructions or video to what I should do. It was running great up until that 2nd ride then the fuel just started pouring out as soon as I turned the tank fuel switch on. I knew it was a gravity system and the carb is mounted nearly level I could maybe try to shift the front motor mount up a tad and get really picky with leveling it if that is needed but this would mean getting pretty anal with it, it is fairly level now but your the experts and I will do whatever you tell me to do. I don't have air but could get a can of air in a cple days if that's what I should do. I bought new gas line and was going to go test the new line without the added fuel filter just to see what happens and I will report back after this test run.I had also emailed the place I purchased and he thinks the float is cracked and is sending me a new one I just read this email now. Is there a float in the bowel that can't be seen? Hmm going to see if I can find a diagram. So don't think I will go through the trouble of bringing it downstairs I tryed to prime it with just a new hose and the gas line won't fill there is a small amount of fuel near the carburator when I depress the primer you can see a small trickle come down the house and gas is still coming out the overflow it has no suction at least not like it did the 1st time I primed it when I 1st primed it the gas came out filled the hose and was ready to go it's not doing that. So I really want to find a full diagram of all the parts and what not and would like to take it apart and find the problem did the cold cause this? or did I just get a bad carburetor? I am fairly confused now. One more thing to add (this seems like a running theme in this thread eh lol) Oil synthetic or non synthetic? I have seen manuals say one or the other so I am confused on this as well.

 

[2door]

I still don't know which carburetor you have. I hope it is the simple NT style and not a CNS. Whichever, they both have floats. Usually a round, donut shaped white plastic part that goes in the float bowl. It should 'float' in the fuel in the bowl. As the fuel level rises the float will rise and press against a fork shaped tang that will in turn press against the bottm of a needle valve that will shut off the fuel flow (or is supposed to). If there is a piece of trash stuck in the needle valve the valve can not close and fuel will continue to flow into the carburetor.
There have been many reports of finding the float full of fuel due to a crack or leak and the float will then not 'float' but sink and can't rise to shut off the fuel.

The carb should be close to level but it isn't necessary for it to be absolutely perfect. A little tilt in either direction won't cause the problem you have. Don't change your engine mounts.

Would it be possible to post a photo of the carburetor? That would help.

Tom

 

[KoolBreeze420]

Its the regular stock carburetor this one http://www.ebay.com/itm/Carburetor-...otor-for-Motorized-Bicycle-Carb-/190735616058

 

[2door]

That is the NT and all the advice we've given so far applies to that carburetor. It really is a very simple device, easily tuned and very little maintenance. Just give it clean fuel and you should be good.
Have you checked that float yet, or the float needle valve? That's where I think your problem is.

Tom

 

[KoolBreeze420]

The float is half full of gas so there must be a crack and this would explain why it worked until it did it took time to fill up to a point where it no longer worked.I Can't seem to get the gas out of it the crack must be small so it basically explains everything perfectly. Thankfully building and testing it right now served it's purpose which was to make sure that everything I got was in working order before my warranty runs out. My new carburetor should arrive tomorrow no later then Wednesday he told me in my email.I suppose if this happened out of warranty I would have to buy a new one I don't see a float in the rebuild kit. I thought the NT carb had the red filter?this one http://www.motorizedbicycle.ca/aftermarket-parts/nt-speed-carburetor-gen-2.html. Nad teh stock I thought was CNS or just a standard carb. Is there a fix for this other then a new one?
And about oil Synthetic or non?

 

[GearNut]

The NT and the NT Speed both use the same float.
A new float is your easiest and longest lasting repair option.

As for synthetic or or petroleum oil, that debate has been around as long as synthetic oil has been around.
Personal preference seems to rule that arena.
This thread gets very in depth on the subject:
http://motorbicycling.com/showthread.php?t=9850

I like synthetic.

 

[KoolBreeze420]

I am so happy my new carburetor arrived and they sent me the NT 2 so now I just need to install this and I got a free upgrade out of it.

 

[2door]

Good for you. Before you install that new carburetor read this thread on sealing it to the intake manifold > http://motorbicycling.com/showthread.php?t=52865
There is some good information/discussion there.

Good luck, have fun and ride safe.

tom

 

[KoolBreeze420]

Well im reall discoraged right now I think I am going to take the float out put it in the CNS stock carb until the engine is broke in then use the NT 2 speed I got to ride about 10 mins then it started chugging and bogging down then refused to start after that. With the CNS standard it ran great no problems except that float. Any suggestions on why it may be bogging down and I couldn't throttle much at all if I tried to throttle it would stall so I thought I'll just run it real slow just above idle and cant get above that as soon as it feels resistance like a hill it boggs down and stalls out this is the best I can explain it in text .So Im thinking I should just go with the standard carb until I break in the motor thoughts, suggestions???