Engine Wont Go full speed

Jelly.T

New Member
Feb 6, 2020
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Hello, I have viewed through a lot of posts and still can't seem to find a proper answer and reason for my problem, so if someone could help me out that would be greatly appreciated. I'm a newbie at motorised bikes but I learnt a lot I got my bike pre-made and was told how to properly maintain it and what to do if problems happen. I got this bike in November last year and rode it a lot at the start but then this happened.

December 20th I rode my bike and took it for a ride I tried to push it a bit as it had not been ridden for a while, I then noticed it slow down going at a certain speed I wondered why this happened and wouldn't go fast. At the time I brought out my phone and recorded how fast I was going it recorded I was going about 28kmh, but this was not fully accurate. I was still in break-in period so I was keeping it slow but when I try to go a bit fast on a straight let's say 30kmh it slows down and doesn't allow it. So after noticing this, I took a break, more of a disappointment break and didn't ride it for about 1 month.

20th January I started it up and off it went I was going way faster than normal but I knew not to go too fast due to it being in breakdown period, but there was nothing forcing it to slow down. I rode it around a bit for today and the next couple days but again didn't push the limit due to it being in break down mode.

I gave it another go about the 27th January and It wouldn't fast again it stopped about 25khm slower than the one before and would not push over that. I asked a friend that said it could be multiple problems so I will state them below:
  • Fuel Clog
  • Spark Plug [I have changed the spark plug about 1 week after getting the bike due to it not starting]
  • Unburnt Fuel
  • Needle
  • Due to me still being in break-in period [I would estimate I have done about 400km and the recommended is 500km]
  • Or could it be something else?
 

Greg58

Well-Known Member
May 1, 2011
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Welcome to the forum, there are several things that I would check first. Look at the spark plug to see what color the porcelain part is, should be brown to dark tan. Black is too rich, light tan is lean. What mixture are you using? If it's 16/1 that could be the problem as well, 24/1 is what I've used on everything after the first. The stock exhaust is very restricted a better pipe or modifying the stock one helps too.
 

Jelly.T

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Feb 6, 2020
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Hello, thank you so much for the reply.
During the breakin period I got told to 16 to 1 ratio but when I am out of the breakin period to go to 20 to 1. The spark plug from when I have looked at it was black. I was also thinking about getting a new exhaust which one would your recommend?
 

Greg58

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May 1, 2011
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A good expansion chamber with a silencer is what works best for me, mine is way too loud without the silencer. You can remove the muffler end cap to test if it won’t bother your neighbors, if it runs better without the cap you’ll know where to start.
 

Jelly.T

New Member
Feb 6, 2020
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Update, I have tried some tests and I believe I have too much fuel going into the motor. I have researched a bit on it but any tips?


I'm am also seeing a lot more smoke than my buddies bike.
 

Greg58

Well-Known Member
May 1, 2011
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The smoke is from the 16/1 mix, mix up a gallon at 4 oz. Of oil which is 32/1 and the smoking will decrease. 32/1 if what I've run in my bikes for 9 years now.