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2 Stroke Bicycle Engines & Kits 2 stroke engine kits need careful installation and setup, find out how from our professionals here!

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  #11  
Old 12-28-2016, 09:57 PM
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Tyler6357 Tyler6357 is offline
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Default Re: 2nd tank of gas, bike wont start

What ratio of oil mix are you using? 16x1 is too rich, use closer to 20-25x1 for break in period. Make sure you are using a high quality semi synthetic 2 cycle oil. Also, you might be losing compression, check for air leaks, the most common spots for leaks are carb/intake connection, intake/intake manifold connection, head gasket/head connection, exhaust/exhaust manifold connection. Start with the basics, to get the engine to start you need (1) fuel (2) spark (3) compression. It sounds like a carb problem to me but maybe not. Are you using an NT carb? Is the spark plug wet or dry after attempting to start it?

Last edited by Tyler6357; 12-28-2016 at 10:06 PM.
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  #12  
Old 12-28-2016, 10:40 PM
crassius crassius is offline
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Default Re: 2nd tank of gas, bike wont start

next step is to see if plug is wet - if dry, then a few drops of fuel in cylinder and replace plug should get you a few pops out of the motor

if plug is wet, it may be bad plug or a compression loss at one of the gaskets, or clogged muffler
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  #13  
Old 12-30-2016, 03:17 PM
kayosdad kayosdad is offline
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Default Re: 2nd tank of gas, bike wont start

Ratio is 16 to 1 - recommendation from gasbike.net where the kit was purchased. Is there a good way to "clean" this incorrect ratio gas out of the engine?

Plug is wet.

I noticed today that there was some debris and fuel residue under where the exhaust attaches. I took the muffler off and it looks like the exhaust gasket is shot.

This exhaust gasket is recommended in other threads - http://www.sickbikeparts.com/catalog...ai67a1pcaoark7

The head gasket appears intact but has paint on it. Not sure if that would make a difference or not

It is an NT Carb.

going to replace the gasket and plug. Other thoughts?
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  #14  
Old 12-30-2016, 09:41 PM
crassius crassius is offline
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Default Re: 2nd tank of gas, bike wont start

starting the motor with exhaust loose is how to test for clogged exhaust - it won't keep it from starting

if plug seems really wet, your motor may have gotten full of fuel from leaving petcock turned on when bike was parked
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Last edited by crassius; 12-31-2016 at 01:05 PM.
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  #15  
Old 12-30-2016, 10:45 PM
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Default Re: 2nd tank of gas, bike wont start

I've found that if the spark plug is wet, you can dry it thoroughly and it will restart. I like to use brake cleaner to get the gas/oil mix off the plug, then let it fully dry. I mean FULLY. The inside of the plug (up where the ceramic is) has to be dry too. You can also use rubbing alcohol.
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  #16  
Old 12-31-2016, 12:05 AM
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Tyler6357 Tyler6357 is offline
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Default Re: 2nd tank of gas, bike wont start

16x1 is too much oil, it will just gunk things up if you use that much oil, I know they recommend 16x1 but everyone agrees that is too much, go 20-25x1 to break it in then switch to 32x1 after burning through several tanks. No need to clean out excess oil, however it sounds like it might be flooding. Try tuning carb. You might want to try a new spark plug too, even if it's good it's always good to have a spare one anyway.
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  #17  
Old 12-31-2016, 12:44 AM
ragdolldude ragdolldude is offline
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Default Re: 2nd tank of gas, bike wont start

Is your gas cap vented? If it's vent is plugged with dirt, or no vet, fuel won't flow very much.
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  #18  
Old 01-05-2017, 06:13 PM
kayosdad kayosdad is offline
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Default Re: 2nd tank of gas, bike wont start

new Carburetor, New plug, replaced blown exhaust gasket, cleaned out gas tank, new gas mix at 25:1

No difference. Will not start

Not sure if this matters or not, but the temp outside was 29F when attempted to start

This was supposed to have been a Christmas gift for my 15 year old. Needless to say Christmas was not what it could have been. Now I am just whining.

Any other thoughts?
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  #19  
Old 01-05-2017, 07:30 PM
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Tyler6357 Tyler6357 is offline
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Default Re: 2nd tank of gas, bike wont start

If the head gasket blew it usually means that it either got too hot or it was missing (4 stroking). Is the head leaking air? If you have an air leak at the head gasket it won't start or if it's just a minor leak it will start but lose all it's power because of the loss of compression. Try shining a flash light on the side of the head/head gasket connection and see if you can see any light shining through from the other side. Go around the entire thing and look closely for any possible air leaks. Sometimes stock heads from China are not built very well and are not flat enough or they have a curve in them which doesn't let the head sit flat. If you blow the head gasket sometimes it will damage the ridge of the head that joins with the cylinder. Take the head off and look closely at the round raised ridge that connects to the head gasket. If you discover an air leak you will probably just get a new head (less than $10 for another stock one, high compression ones like a Fred-Head cost more but cool the engine better). However, sometimes it's the cylinder that is not flat enough and must be replaced or sanded down to make a flat surface, use a flat surface, like a piece of glass, to sand it to make it flat or you can get a new cylinder.

http://www.ebay.com/itm/Cylinder-Sla...dWL4SS&vxp=mtr

http://www.ebay.com/itm/MOTORIZED-BI...JW7H8r&vxp=mtr

If you don't find a leak at the head it must be something else. Other possibilities are: damaged piston, a carb jet that is too big and flooding it, a broken ring, carb needs to be tuned properly, air leak somewhere else, no spark, timing adjustment, clutch slipping.

Last edited by Tyler6357; 01-05-2017 at 07:35 PM.
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  #20  
Old 01-10-2017, 07:05 PM
kayosdad kayosdad is offline
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Default Re: 2nd tank of gas, bike wont start

Took the top end off. Everything seems to be fine. Only problem is I have no idea what I am looking at. The only thing that seemed off was debris was everywhere. Like a mixture of sand and rubber.

What should I be looking for on the piston? In the cylinder?
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