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Runs fine.. then literally dies

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I have a 1973, 74, or 75.. not sure which one.. kawasaki MC1 90.. It was bored out to something else higher 4 years ago considering i couldnt find any parts for it at all.. So my uncle rebuilt it all and everything.. last year it started doing this.. it will run great and be incredibly strong for id say like 20 minutes :? but then it will just not take any throttle and die.. it will barely idle. then if i slowly rev it up it will be erratic and stay reved and the only way to drop it down is flip the kill switch up then back to run real quick, then i can shut it down.. its odd.. also there is smoke coming from the engine after a run, but i think that that is just burning off oil from sitting all winter outside full of gas and everything.. i brought it in two days ago. chekced the floats and cleaned the carb. everything seemed fine.. put in a new spark plug aond started up second kick.. i am totally baffled by this, any help would be great

Also, i realize its old, but its all i got, no money, and im looking to get a yamaha 125.. so untill then, (like one more summer i need out of this) i would like to keep this thing runing

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I take it that that bike is a 2 stroke? An engine needs these things:

Spark

fuel

compression

relatively close timing

If it has those it will work. check the fuel, that sounds like the problem.

Is the choke on? Are you leaving it on the whole time? Thats a problem.

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No, choke only goes on when i first start it that day, and how do i check compression? and timing, never done it.. can i check it anyway?

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as for fuel, i had to put ina different seperate petcock, so i just drilled out the original one.. do you think its not letting enoigh fuel through? i have noticed after liek 3 seconds or longer inn second gear when i shift down and start to accelerate, i have to let it sit.. for a second to "fill back up on fuel?" youi think it is runnign lean bc of not enouigh fuel?

Also it doesnt have a constant smoke trail... unless i let it sit there for a second then go, then it has smoke

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My xr has smoke now, I think oldman winter did something to it. You can buy a compression tester from sears. You put that in the sparkplug hole and kick the motor over a few times. To check for fuel, take the sparkplug out and push the kick starter over with your hand kinda fast a few times. Smell fuel? don't touch the sparkplug when you are kicking the bike over.

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i have narrowed it down to fuel, as i have not tested the other things beside spark, it would have to be fuel, i went out and started it up, and it did that no throttle thing right away... i saw that my original petcock that is still on there was facing up, i turned it to the middle and it worked.. so now i have to find a way to bypass that original petcock, because it is still on there and it only dribbles fuel, its not a constant stream.. so it should definatly be fuel, which would explain why it is running hot, (it is runnign lean.)..

any ideas how to bypass the original petcock?

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Check your gas tank vent too.

I dont even know where my gas tank vent is. im sure there prob is one, but i do not kwo of it..lol

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i have narrowed it down to fuel, as i have not tested the other things beside spark, it would have to be fuel, i went out and started it up, and it did that no throttle thing right away... i saw that my original petcock that is still on there was facing up, i turned it to the middle and it worked.. so now i have to find a way to bypass that original petcock, because it is still on there and it only dribbles fuel, its not a constant stream.. so it should definatly be fuel, which would explain why it is running hot, (it is runnign lean.)..

any ideas how to bypass the original petcock?

Can you get a new one? You are just talking about the valve that turns the fuel flow on and off, right?

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The cap doesnt use a vent hose, it has an internal baffel for venting.Take off your tank and clean it. Petcock too. It is full of rust or dirt.

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well i may have been low on gas also? i dont have a reserve... i went out and within a minute it died.. couldnt get it started i was getting upset lol.. take off the line to the carb, and turn on fuel.. nothing.. so i was completely out of gas.. it died while idling.. so .. i filled it up some and ran it again.. never bogged.. lol. but i was only out for not very long.. hopefully i have time again today to test it out more

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well i may have been low on gas also? i dont have a reserve... i went out and within a minute it died.. couldnt get it started i was getting upset lol.. take off the line to the carb, and turn on fuel.. nothing.. so i was completely out of gas.. it died while idling.. so .. i filled it up some and ran it again.. never bogged.. lol. but i was only out for not very long.. hopefully i have time again today to test it out more

lol, I did something like that once. I took the carb on my xr100 apart because I thought the jets were clogged, and what was wrong is the fact that I didn't have the fuel valve on reserve. So dad yelled at me a whole hell of a lot, then when it ran again he laughed at me. If you want the whole stroy pm me, I don't want to be a complete thread hijacker.

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Remove it, diassemble it, and clean it. If the outlet hole needed to be larger they would have made it that way from the get-go.

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well it didnt work 4 years ago.. i was only 11 so i wasnt too much up to date on what was wrong.. i got it as a b day present from my uncle and dad.. and it doesnt loooked drilled... i think we have that second one on there so it doesnt leak.. but it doesnt seem like the original one on there doesnt work right.. but i just went out, and it was all perfect (well one slight occasion when it bogged for like half a second)

Sadly, i think it just needed more gas in the tank lol

but any more suggestions would be great

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