KymcoForum.com
General => General Discussion => Topic started by: blue on March 31, 2016, 01:21:09 PM
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What all makes your 50 cc scoot back fire.its all stock only thing done to it is new gas lines.
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What all makes your 50 cc scoot back fire.its all stock only thing done to it is new gas lines.
Have you tried putting old lines back on and run it?
Any change in fuel line inside dimensions?
Stig
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Have you tried putting old lines back on and run it?
Any change in fuel line inside dimensions?
Stig
Ya the dimensions were bigger so I got some stock gas line and trying that. ill see how it gos if it ever stops raining.
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stock gas lines back on Now its hard starting. maybe the choke is bad.............how often do they need replaced.
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OMG... do I feel like a fool. All it was is the bad gas line was pluged up.Not letting the bad gas out. on the carb...the littlest things.
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Scoot is still backfireing. I was told there is a bad gas valve the size of a needle next to the main valve that is stuck shut. Only way of fixing is to replace the top end. so far I put over 2000.00 miles on the scoot and it still gets up[ to speed the way it should I can do 45 easy. I now have a nick name popy.O well they can hear me comeing now................
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"Bad gas valve next to the main valve..." and this is in the top end which needs to be replaced...? I am curious who told you this? The top end and the carburetor are two separate assemblies that do work together.
Karl
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"Bad gas valve next to the main valve..." and this is in the top end which needs to be replaced...? I am curious who told you this? The top end and the carburetor are two separate assemblies that do work together.
Karl One of the guys I ride with said that's the only thing it can be. sense its not the carb . the carb is new and so is the muffler and all the gas lines and I have no air leaks. the scoot drives and runs great better then it ever did after the new carb. So I just learn to live with the backfireing after I start to slow down.
they could be wrong......
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The reason I ask the question is, the statement does not make sense. I may be too picky about words but its a big deal to replace the top end so one needs to know just why before one spends a lot of moolah throwing parts at a problem only to find the recommendation was just a guess. That is what dealer techs do because they don't know how the systems work. Some of the common causes of backfiring are: 1. Too lean of mixture; 2. Retarded timing; 3. Temperature of engine too high; 4. Valve timing incorrect. Lets explore these four and find the one or more that may be causing the problem. Is the bike stock or has it been modified? What were the mods if any? What is out of whack if stock? And so on..
Karl
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Gentlemen, I need some advice. My DT 300i is a 2012, I got it in October '15. It has less than 1800 miles. I noticed these little cracks in the tire. I don't know how or where it sat before I bought it. Should I replace the tires? Or should I wait? You guys have helped me in the past, I trust your opinions! Thanks
- Rich
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Have you tried putting old lines back on and run it?
Any change in fuel line inside dimensions?
Stig
Isnt there a timing adjustment on the scooter near the stator some where. I always equated backfiring to a valve timing issue.
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Hey, Pipster! You hijacked this thread! Those cracks indicate the tires are quite old and should be replaced. Personally, I don't like the Maxxis. I think they are a really cheaply made tire and could not wait to replace them on my DT.
Karl
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What all makes your 50 cc scoot back fire.its all stock only thing done to it is new gas lines.
Would a clogged muffler cause backfiring? Is it a 2 stroke?
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The reason I ask the question is, the statement does not make sense. I may be too picky about words but its a big deal to replace the top end so one needs to know just why before one spends a lot of moolah throwing parts at a problem only to find the recommendation was just a guess. That is what dealer techs do because they don't know how the systems work. Some of the common causes of backfiring are: 1. Too lean of mixture; 2. Retarded timing; 3. Temperature of engine too high; 4. Valve timing incorrect. Lets explore these four and find the one or more that may be causing the problem. Is the bike stock or has it been modified? What were the mods if any? What is out of whack if stock? And so on..
Karl
The only mods is lighter rollers. and new stock carb new stock muffler.the timeing has been resit. maybe the lighter rollers threw the timeing off............
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Sorry, I thought I posted on the other thread. I get up at 3am, I probably posted before my 2nd cup of coffee. Thanks for the input.
-Rich
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Exhaust leak at the flange ?? Incorrect fuel mixture ??
A little google of scooter backfiring came up with those.
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Gentlemen, I need some advice. My DT 300i is a 2012, I got it in October '15. It has less than 1800 miles. I noticed these little cracks in the tire. I don't know how or where it sat before I bought it. Should I replace the tires? Or should I wait? You guys have helped me in the past, I trust your opinions! Thanks
- Rich
Sent from my iPad using Tapatalk its all good have a cup of coffe on me.....your tires are weather checked.I would get new befor you are left pushing the scoot home.
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Did some fine tuneing today. Soon as I turn the gas mix screw to about 11/4 turns the scoot runs its best. But only gos 30 to 35 mph...with it 21/4 turns or less I can do 40 to 48 but then the back fireing starts.....Look like I need to go up a size in my main jet.
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That mixture screw usually is for idle speed. You are on the right track with a larger main jet.
Karl
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Ok back to the backfireing.I pluged off the big hose that comes from the bottom of the main head.took for a small ride.and the back fireing is gone. What gives. Is it safe for the scoot to have this pluged up.
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Pic.
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Pipster , If that is a maxxis tyre, run as far as you can from it.
I had maxxis on my 500 which also developed cracks like that, but even worse, one right across the circumference.!
Also I noted that the front tyre developed uneven wear pattern.
In my opinion, they are an inferior product.
Since changing to Michelin city grips, all such problems are non existent.
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Back firiing = timing on most problemos, =premature/after detonation. Just a cause maybe?