Engine won't fire when iI release clutch lever, revs when pulled in

illbill713

illbill713

New Member
Hi all. I got a sd stinger 66cc engine kit . got everything hooked up. When i first installed i noticed i couldn't pedal the bike when pulling in the clutch lever, so i loosened the flower nut about 1/4 turn. Worked great, now i was able to pedal. Now let me skip ahead I just tried to take the bike out, i have the enige mounted on an old ladies style Huffy cruiser with the gas tank mounted on a rear luggage rack. I'm pedaling with the clutch lever pulled in, picked up good speed, and released cluitch lever. The results are the engine puttering i even noticed some gas/oil come out by the spark plug area. Then I pulled the clutch lever in a bit and twisted the throttle. This made the engine rev and sound like a running engine should sound (minus the forward motion from the torque of the engine), but upon releasing the clutch lever it went back to the struggleing puttering sound.I had choke on about an eighth of the way w/ carb primed and spark plug had gas on it when i pulled it out to inspect it. I disconected the kill switch wires and the white one, and capped them all. I put in a fuel filter, i tried switching the spark plug to a ngk b6hs, then back to the factory spark plug, both:-|| gapped at .035 inches. I've beeen having a problem with alignment but flipped the rear sprocket with the teeth further away from the spokes, as well as took off one more chain link and that seemed to help along with the factory tensioner set-up . Im using a kinda cheap synthetic 2-stroke oil from Big Lots at a 16:1 ratio. Does anybody know what might be my problem here?
 
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Put the flower nut back where it was then retighten your clutch cable.

You said, "i even noticed some gas/oil come out by the spark plug area". What do mean by this? Is the plug tight? Is there a gasket on the plug? Are the cylinder head nuts tight?

Reduce your oil mix to no more than 24:1. 16:1 is too much oil.

Have you confirmed you're getting ignition (spark)?
Is fuel flowing to the carburetor?
Is the choke open?

Get back to us with a little more information. We'll help get you on the road.
Tom
 
Ok, cool. I'll try retightening the flower nut and clutch cable and bleed out my old gas and try some fresh stuff at a 24:1. Now I know there is fuel getting to the carb because I unscrewed the drain screw at the bottom of the carb and gas flowed out. As far as the choke goes I've been trying to start it with the choke on and it bogs, so I used it at about 1/4 to 1/2 way open and didn't notice a bogging noise. Now at the plug where I said i noticed fluid in the area, there are small traces of gas/oil mix in front of the plug, but the plug is set in tight with a .035 gap. Now when I first started installing this I got a bit confused on how the wires where actually suppose to match up, now I have it good, but I don't know if I could've damaged something before I did away with the kill switch and capped the white cable. Not sure if I'm getting spark and I don't really know how to check for spark. What would be an easy way to do that?
 
Remove the plug then reconnect the plug wire. Lay the plug tight against the cylinder head cooling fins and roll the bike forward at a good pace while observing the electrodes of the plug. You should see a spark jumping between them. If you have a way to suspend the rear wheel you can also do this test by pedaling the bike, clutch engaged.

I've attached a wiring diagram for you to follow if you're uncertain about the ignition wiring.
If you see no spark, start by checking your wiring against the diagram. The kit supplied push-on connectors are notorious for bad connections. We suggest soldering those connections then protecting them with heat shrink tubing. Make certain that white wire is not touching anything. It should be capped and wrapped securely.

These little engines have a variety of choke requirements. Some like a lot, some don't need much, or any at all. You'll have to experiment to find out what your particular engine needs. In colder temperatures, they usually like a little choke until the engine reaches operating temp.

Get back to us with what you find.
Tom
 

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Okay, just took my bike out of the shed and tried firing up. I had earlier on retightened the flower nut inside the crank case to where it was snug and retightened the clutch cable to pull in a little bit of slack. I re-checked my wiring but haven't looked to see spark. Haven't changed my gas/oil ratio yet, either, but i had a little bit of pre-mix left in the tank after draining it so i decided to try and spin my engine. While empting my gas tank I also noticed that with the petcock lever fully depressed to the left botton side where it says "off" that the gas is actually still flowing as if it where on "on", and that the petcock lever needed to be directly pointed towards the "off", and not all the way past the oppisite side of where it says "on". So I could have been just letting my bike sit with the petcock turned on, which I'm not sure what the exact effects would be. So I just rolled down the street with the little bit of gas left in my tank, pedaled with the clutch lever held in. Picked up speed and I released clutch lever. Now the engine ran but it felt very rough, and not very sure footed . I noticed that when I held the clutch lever in slightly that the engine would idle, without giving it throttle, but when I gave it throttle the engine seemed to stuggle.I will try new gas/oil ratio tomarrow and try messing around with the choke some more, which seems to be part of my problem but I'm not sure.
 
Alright! I got everything up and running. Thanks for the help. I had to keep the choke all the way open when starting and operating. I also changed the fuel ratio to 24:1. Retightening the flower nut seemed to help things a bit, too. Now the only problem is vibrations from the chain due to the factory tesioner wheel, which doesn't roll at all. Figuring on a mod for that in which I'm able to do with the tools i got so the tensioner rolls with the chain.
 
Most, if not all of the kit supplied tensioner brackets require a slight twist to get the wheel to align with the chain path. That's because the chain stay is not parallel with the wheel/chain/sprockets. A large Crescent wrench will work and a bench vice makes it an easy fix. Sight along the chain and tensioner wheel from the rear of the bike looking forward to see how much 'twist' you need to put in the bracket.

Use the search feature at the top of the page, type in 'Tensioner' and you'll find lots of reading on what to do and what not to do with your tensioner wheel/bracket. It is a controversy better left to you to decide for yourself instead of opening that can of worms again here.
Good luck. Keep us posted.
Tom
 
Thanks for responding to my posts Tom. I had already bent the bracket to run "more" parralel with the chain on the kit, instead of the chainstay. I did read about about that on another post, too. My ploblem with the stock roller guide is that it doesn't roll along with the chain. I just went out for a ride without the tensioner and noticed the chain "skipped" twice over the drive sprocket. I let off the throttle as soon as I felt it and pulled in the clutch on each time, I know now from this ongoing process of dialing this thing in that the chain skipping like that could lock you up. Still, not too bad for a 10 minute ride. I've taken as many links off my chain, without coming up short, as I can. Now I'm trying, to use a rear sprocket from and old single speed bicycle hub and mount it, somehow , using the kits factory tensioner bracket. Until then, I'll just be breaking in my engine at a low rpm, probally without the tensioner. I've taken notice of the pictures and comments on here about different tension mods, I personally feel that you need a tensioner to have a smoother ride. Maybe if my bike's frame wasn't so light it wouldn't though.
 
Take the roller off and you should have a roller, the screw, and a cylinder piece. Maybe sand the screw a bit thinner to give more clearance once inserted into the roller and other cylinder piece.
It could simply be that the screw is a bit thick so it's a bit tight in the hole.
 
Good suggestion, but i found today what was probally making my chain skip, I didn't realize how important it was to slightly close the choke while excellerating and opening when slowing down or idleing. So while playing with the choke and adjusting the idle screw and giving it throttle then going back to idle, I think I got how this thing is going to work best. The tensioner will probally sit in a drawer for now. I also shortened my spark plug gap to about .025, which I thought gave the engine a more consistent sound. I do beleave my main problems on this project was sprocket alignment, the flower nut being loosened and not retightened, and over looking the on/off position on the petcock and choke.
 
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