Struggling to start engine

Petter

New Member
Oct 4, 2020
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I can’t start the engine. Do not know what the problem is. Sometimes it does not even fire. I have checked for spark and there certainly is. Carburettor is giving fuel as when I spin the wheel without the plug I can see a mist of air/fuel mixture. Should be no air leakages, I have mounted to cylinder head back on with perfection. Help. Here is a video of me trying it down a steep hill, when it goes fast it will fire sometimes.
 

LR Jerry

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Dec 19, 2011
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Rockwood, TN
You need to post better information about the engine itself. Show pictures of the engine itself. A fly by video only let's us know a little about what's happening. Mist shouldn't be coming out of the carburetor it should be going into the cylinder. Did you ground out the plug and test it in dim light? There could be air leaks or valves may need adjusting.
 
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Davideo

Active Member
Feb 25, 2020
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I can’t start the engine. Do not know what the problem is. Sometimes it does not even fire. I have checked for spark and there certainly is. Carburettor is giving fuel as when I spin the wheel without the plug I can see a mist of air/fuel mixture. Should be no air leakages, I have mounted to cylinder head back on with perfection. Help. Here is a video of me trying it down a steep hill, when it goes fast it will fire sometimes.
Petter, when it begins to fire close choke and open throttle about 1:3 way open.
I made a little video for cold starts which may help if your bike is working properly.
 
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carburetor al

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Jun 14, 2020
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Hi Petter These things may help. There is an adjustment screw on the carb. On three different carbs I've looked at it was way out of adjustment. Turn it in carefully. When you feel it bottoming out stop turning right away. This gives you the point to set the screw. Turn it out 1 and 1/2 turns. You readjust fine tune after the motor is warm. The other big problem found was in the cdi. The wire going to the CDI
is actually screwed on something that looks like a wood screw. See if you can turn it in or out. If you can work it loose, tighten it. Same on the spark plug end of the wire.. What you are trying to do is get better contact. When I solved these minor problems my motor started. Hope this helps!
 
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Citi-sporter

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Jun 16, 2014
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It would be a good idea to get the cover back on your gear-case.

Also loosen the carb's float bowl drain screw with the fuel tap on to see if fuel is getting to the float bowl. You don't need to completely remove the drain screw, just loose enough to see if a little raw fuel weeps out from the threads. Recheck your float height if there is no fuel present. The little tangs on the float arm are pretty malleable and can be easily bent out of adjustment. Clean your spark plug of raw fuel if you're over fueling, and take out the spark plug and ride the bike around with the throttle wide open and the fuel tap off, this will clear out any raw fuel sitting in a big puddle in the bottom of the crankcase. Raise the metering needle circlip one notch if the engine is running too rich.

Carb help topics here

More NT carb tuning tips here..
 

Davideo

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Feb 25, 2020
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I’m finally back, here’s a short video of me testing the two things where we left off.
Petter. after watching your video several times, it strikes me that it is far too easy to run your engine through many compression cycles by flipping the wheel with one hand and I am sure that could not be done with what I would call an engine with good compression. Perhaps the compression ring is broke or missing on your engine. Before taking off the cylinder locate a compression gauge and check the engine. The pressure should read between 80 - 100 pounds per square inch (about 6.5 Bar).
 

Petter

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Oct 4, 2020
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1 minute ago
Okay so im back arter a while, i really didnt want to order a new kit, but after hours of trying to start it without success I had to. I arrived yesterday, and I finally swapped cdi, throttle and engine block. It took a while but I got it done l. I biked away and it started on the first attempt. It was amazing. However, I noticed I forgot to install the muffler, and it was super loud. I couldn’t keep it going as it was late and I was making a ton of sound. I tried the kill switch and it stopped right away. As I was installing the muffler I noticed the carburettor was leaking, as the previous one. I have now had three different carbs. Anyway I installed it quick so maybe just a spoon of gas got out of the carb and on to the block. I tried starting it with the muffler on, it was a lot weaker now. It could barely ever pull me up the slightest off hill without stopping. I had to kick to keep going. I was happy either way as my engine finally was running. After a 5 minutes long trip I went back home to let it rest as I have read you shouldn’t push these things too hard to start off with. I let it sit for 10 minutes before I couldn’t help myself but to go for another short ride. Then it happens again. It would not start. I tried 6 times and I just ran with no signs of ignition what so ever. The last two attempts it ignited like 5-6 times but not in a row, so it would not start. Any tips on what the issue could be? There is not a lot of fuel in the tank. I only had about 0,2 litres left of the last bottle. Here is a video of me right after I installed the muffler on the trip.
Here is a small picture of the current setup, and the small amount of gas in the fuel line.

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