Engine won't turn over

Timo Tay · Nov 24, 2012

Alright, so in all I'm fairly new to this. I put together my bike, after much struggle I got it to work, and it worked fine for a whole month. Now when I try to start it, release the clutch, it revvs up and then I can start pedaling keeping the engine in idle,throttle works and I can hear it revving but it refuses to turn over no matter my speed. I checked the carborator seemed fine, no cloggage or anything. I could really use some help on this thanks. :-||

Mr. Minecraft · Nov 24, 2012

Ok so first "turning over' refers to the piston's movement in the cylinder. If you can start the bike and it is revving up but not PULLING you, then your clutch needs to be adjusted. Take the cover off the right side of the engine and release the clutch. push the clutch plate in and tighten down the flower nut. Then loosen it a bit until you can roll the bike without the clutch catching when it is disengaged.

Timo Tay · Nov 24, 2012

Gracias ill give it a go

2door · Nov 24, 2012

Mr. Minecraft said:
Ok so first "turning over' refers to the piston's movement in the cylinder. If you can start the bike and it is revving up but not PULLING you, then your clutch needs to be adjusted. Take the cover off the right side of the engine and release the clutch. push the clutch plate in and tighten down the flower nut. Then loosen it a bit until you can roll the bike without the clutch catching when it is disengaged.

DO NOT START MESSING WITH THE FLOWER NUT until you have determined if that is the problem. This is BAD advice to someone who doesn't undertand what the flower nut does and how to adjust it properly. If he can start it by pedaling then it's a good indication that the clutch isn't slipping.

I'm not clear on what the man's problem actually is. Messing with the clutch is not the place to start.

To the OP, could you please be a little more specific about what happens after the engine starts?

Timo Tay · Nov 24, 2012

Alright cool, so I start it up right, hold down the clutch start to roll with ease, as soon as I let go it makes a promising start up sound and then goes to an idle state which I cant get it started from there no matter how much I pedal or revv it and it slowly will goto a stop. Would it help if I got you pictures of my mobile?

2door · Nov 24, 2012

Are you certain the engine even starts? Is it running when you have the clutch pulled in and the bike setting still or do you simply hear engine sounds when you're pedaling? I'm still not clear on what is happening but I suspect your engine isn't running at all.

If it does start and run but will not accelerate then you might have a throttle cable/carburetor problem. What carb do you have? In fact I just realized we don't even know what engine you have yet but we're assuming it is a Chinese 2 stroke, in-frame.

Tom

CTripps · Nov 24, 2012

Pics always help.

Timo Tay · Nov 25, 2012

Alright if you need more intricate pictures just say when.

Bike itself: http://i940.photobucket.com/albums/ad246/Steele-Associate/securedownload1.jpg

Carborator: http://i940.photobucket.com/albums/ad246/Steele-Associate/securedownload.jpg

Spark Plug: http://i940.photobucket.com/albums/ad246/Steele-Associate/securedownload3.jpg

Lines: http://i940.photobucket.com/albums/ad246/Steele-Associate/securedownload2.jpg

Timo Tay · Nov 25, 2012

And yes, when I start pedaling effortlessly as if the engine would start, Ill pull the clutch again and the engine will shut down.

fatdaddy · Nov 25, 2012

Then it's not starting. Is there fuel in the tank? ( long story.)
Are you still using the spark plug that came with your kit? Are you using an in line fuel filter? Those hardly ever come with the kit, and an in line filter is a MUST HAVE. If your carb is clogged it will not start. If you get back and say you're not using a gas filter, then one of us will go through with you on how to clean your carb, check for fuel flow, ect. The gas cap will knock chunks of paint off the tank neck and clog EVERYTHING.
Did you use the white wire for the kill switch? I hope not. (ask me why.)
fatdaddy.

nightcruiser · Nov 25, 2012

I am getting the idea that your motor is turning over due to you pedaling it rather than it actually running, could be wrong, your description leaves a little wiggle room in diagnosis...

Could be a handful of problems, but I am gonna suggest that you check the torque on the head bolts to make sure they didn't come loose. If your head comes loose it can form a leak and you will lose your compression, the motor wont run without compression. The reason I am suggesting perhaps you have a head leak is it sounds like your motor is turning over quite easily when you are pedaling, the compression from the motor should provide a fair amount of resistance against pedaling. If your head has come loose and you have no compression, however, the motor will turn over quite easily....

There are a host of other things that could be the culprit as well... In order for the motor to run you need air, fuel, spark and compression. Things can go wrong in each of these areas....
The inline fuel filter (in the end of the fuel valve) can get clogged and prevent/limit fuel flow. The main jet in the carb can get clogged and prevent fuel from entering the cylinder. The air filter can get oily and prevent proper air flow. The spark plug can get fouled and prevent spark, the plug wire or plug boot can also take a crap on you and prevent spark. These are the most common and simple issues, there are also more complex problems that could be occurring as well but you should narrow down the possibilities by checking the obvious first.

Another common problem is with some motors if you leave the fuel valve on while the bike is sitting (not running) fuel can seep down into the motor and flood it out pretty badly, and flooded motors don't like to start. To cure a flooded motor the best thing is to pull the spark plug, dry it out, then crank over the motor a FEW times with the plug out to expel and excess fuel that may be built up in the motor. (make sure there is no spark or flame to ignite the fuel that may come from the spark plug hole).
That said, a flooded motor would likely turn over a bit harder rather than easier, and it sounds like your motor turns over pretty easy, so I would look for reasons you might be losing compression.....

CTripps · Nov 25, 2012

Timo Tay said:
Alright if you need more intricate pictures just say when.

Bike itself:

Carborator:

Spark Plug:

Lines:

Nice looking bike, Timo.

A fuel filter would be a good thing, yes. You'd be surprised at how much gunk there can be floating around in the bottom of the tank. With the fuel line off the carb, how does the flow look if you open the petcock? And while I'm thinking fuel delivery, have you pulled and checked your spark plug after trying to start to see if the end is wet?

I'm not a fan of where your CDI is mounted, but only because your magneto wires are way too close to the engine.. if they rub on it when it gets got, the insulation will melt and they will short out. At the least, they'll shut you down. Many will tell you to lose the quick connectors and solder the blue and black wires together, too. The stripped plug wire wrapped around the plug tip also may not be doing the job, that's also a cheap and easy fix. (copy and paste replace spark plug boot into the search box above, it's a 5 minute fix)

Keep us posted on how it goes.

Timo Tay · Nov 25, 2012

Yeah yeah, I mean the thing ran good for month, got the filter, gas was flowing at an acceptable amount, and no the white wire is insulated. But I am using the same spark plug with the kit, I checked this already though, an extra came in the kit after it broke down and I switched it out but still nothing. But if you could still go over on cleaning the carb that'd be noice.

Timo Tay · Nov 25, 2012

CTripps said:
Nice looking bike, Timo.

A fuel filter would be a good thing, yes. You'd be surprised at how much gunk there can be floating around in the bottom of the tank. With the fuel line off the carb, how does the flow look if you open the petcock? And while I'm thinking fuel delivery, have you pulled and checked your spark plug after trying to start to see if the end is wet?

I'm not a fan of where your CDI is mounted, but only because your magneto wires are way too close to the engine.. if they rub on it when it gets got, the insulation will melt and they will short out. At the least, they'll shut you down. Many will tell you to lose the quick connectors and solder the blue and black wires together, too. The stripped plug wire wrapped around the plug tip also may not be doing the job, that's also a cheap and easy fix. (copy and paste replace spark plug boot into the search box above, it's a 5 minute fix)

Keep us posted on how it goes.

Thanks gov, and yeah I'm going to check the compression of my motor as stated above then, sounds like that could be the problem. As for the CDI it was really all we could manage with the fat frame and all. And yeah I haven't left my gas switch on either. As for the soldering, sounds like a plan but I'm thinking I should get a whole new CDI all together?

JonnyR · Nov 25, 2012

as far as i see the plug wire is a issue it unscrews from the CDI i would think about one for a car/boat/tractor/motorcycle and screw that one in

as far as mounting the CDI i would use a zip tie or 2 to mount it on the front tube

and sodering is the way to go after you get everything to work it keeps everything solid dont forget to wrap them in electrical tape or use shrink tube on them

nightcruiser · Nov 25, 2012

Typically a brand new motor can have lower compression before it has been run, the motor may turn over pretty easily at first. After it has run and the rings have seated the compression goes up and it gets harder to make the motor turn over (need to be rolling faster or the rear wheel will skid when you pop the clutch) Some motors have more compression than others, you can kinda tell how your compression is by how hard it is to get the motor to turn over when you pop the clutch....
Most people don't have compression testers so the easiest thing to do is check that all the head bolts are evenly and properly torqued. It is common for head bolts to vibrate loose, if they loosen enough you will get leaks under the head because it is not held together tightly enough. Checking the head torque is something you will probably need to keep after with a china girl...
I had this issue with mine at first, and got tired of checking up on the head bolts. I ended up buying an upgraded stud kit (from SikeBikeParts.com). When I installed the studs into the block I used RED Loctite, when I put the nuts on the head I used BLUE Loctite... I should warn, RED Loctite is for a permanent bond, so you do not want to use it on the original kit studs which are very cheap and prone to fail. To remove a stud with RED Loctite you would need a blow torch, a factory stud would likely twist off leaving half a stud in your block, pulling a stud with red loctite wouldn't be fun. That said, with quality studs it has worked out great for me, I haven't had to re-torque the head for 1000 miles now...
There are people on both sides of the question "To Loctite or not to Loctite", one thing is for sure, the vibrations and low quality of the hardware that comes with these kits pretty much assure you that things are going to come loose. I for one fall into the loctite camp, this year the only bolts I had to tighten were the ones I didn't use loctite on...

fatdaddy · Nov 25, 2012

Timo Tay said:
Yeah yeah, I mean the thing ran good for month, got the filter, gas was flowing at an acceptable amount, and no the white wire is insulated. But I am using the same spark plug with the kit, I checked this already though, an extra came in the kit after it broke down and I switched it out but still nothing. But if you could still go over on cleaning the carb that'd be noice.

I'm gonna try to make this as simple as possible. First, you can either remove the carb from the bike or not. I just leave it on myself but I've been doing this a LONG time.
FIRST, Turn off gas at petcock. Then remove the bottom float bowl, this usually is only two screws. Put a rag under it to catch the excess fuel. Sticking down from the bottom of the carb you will see a copper looking tube, this is the jet and jet tube. At the end of this tube is the jet. unscrew the entire tube with the jet still attached, Then remove the jet from the end of the tube. Hold them both up to the light and you should be able to see through them. Blow em out anyway! Put the two back together and reattach to the carb. Don't put the bowl back on yet. First part done.
The EASY way to do the second part, without removing the float tangs, the tang pin and the float needle is the way I do it. I don't like dropping tiny crap under my work bench or on the driveway. Remove the fuel line from the inlet at the carb. Unscrew the inlet fitting.(you will see the valve needle in the hole) This is your inlet fitting AND your float valve needle seat. Again, hold it to the light, Then blow it out anyway. Screw it back in BEING VERY CAREFULL TO MAKE SURE THE NEEDLE IS CENTERED IN THE FITTING.
Now your almost ready to put the bowl back on. Inspect it closely for crap in the bottom, Blow it out anyway. Make sure also that the tang pin didn't slide out a little, this will interfere with the bowl seat. Drop the white float back into the bowl and Put the bowl back on the carb, Wiggle it to insure a proper seat. Tighten the two screws, turn on the petcock and start yer bike.
Any questions, feel free.
fatdaddy.

fatdaddy · Nov 25, 2012

nightcruiser said:
I am getting the idea that your motor is turning over due to you pedaling it rather than it actually running, could be wrong, your description leaves a little wiggle room in diagnosis...

Could be a handful of problems, but I am gonna suggest that you check the torque on the head bolts to make sure they didn't come loose. If your head comes loose it can form a leak and you will lose your compression, the motor wont run without compression. The reason I am suggesting perhaps you have a head leak is it sounds like your motor is turning over quite easily when you are pedaling, the compression from the motor should provide a fair amount of resistance against pedaling. If your head has come loose and you have no compression, however, the motor will turn over quite easily....

There are a host of other things that could be the culprit as well... In order for the motor to run you need air, fuel, spark and compression. Things can go wrong in each of these areas....
The inline fuel filter (in the end of the fuel valve) can get clogged and prevent/limit fuel flow. The main jet in the carb can get clogged and prevent fuel from entering the cylinder. The air filter can get oily and prevent proper air flow. The spark plug can get fouled and prevent spark, the plug wire or plug boot can also take a crap on you and prevent spark. These are the most common and simple issues, there are also more complex problems that could be occurring as well but you should narrow down the possibilities by checking the obvious first.

Another common problem is with some motors if you leave the fuel valve on while the bike is sitting (not running) fuel can seep down into the motor and flood it out pretty badly, and flooded motors don't like to start. To cure a flooded motor the best thing is to pull the spark plug, dry it out, then crank over the motor a FEW times with the plug out to expel and excess fuel that may be built up in the motor. (make sure there is no spark or flame to ignite the fuel that may come from the spark plug hole).
That said, a flooded motor would likely turn over a bit harder rather than easier, and it sounds like your motor turns over pretty easy, so I would look for reasons you might be losing compression.....

Lookin at the pics I don't see any indication of blow by at the head. A little exhaust leak at the fitting, but no head leak. I once rode a bike across town to get home with the head blowing like Ahabs whale. No power but it made it home. What I don't see also is an in line fuel filter. The screen filter in the tank is NOT ENOUGH, gotta have an in line. I'll bet his carb is clogged up tight.
fatdaddy.

Timo Tay · Nov 27, 2012

Alright ill give it another go, I cleaned it before or so I thought but it does seem like its trying to run on fumes. thanks mate.

fatdaddy · Nov 27, 2012

Timo Tay said:
Alright ill give it another go, I cleaned it before or so I thought but it does seem like its trying to run on fumes. thanks mate.

Just follow post# 17 exactly and you'll be fine. And while yer at it, unscrew the petcock and clean the screen filter.
fatdaddy.

Engine won't turn over

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