Planet Minis

thorwarrior915 · 11-24-2007, 10:15 AM

I have a 1987 Z50R 6V points motor with a takegawa stock head 88 kit that keeps fouling plugs. Carb is clean... i'm ruling the carb out of the equation. Is this a sign that the electrical system is weak? When I ground a plug to the head to check for spark it is throwing some huge blue sparks. Doesn't look weak... but I haven't tested it with a voltmeter or anything yet.

Why does a little fourstroke foul plugs? I'm assuming its a problem of too much fuel... but with a stock 13mm carb on an 88cc motor... i wouldn't think that would be the issue (stock main jet). I had it running beautifully. Then I went to start it and it wouldn't go. Pulled a plug out of another bike and it burped and ran poorly, then quit. I went and got a couple fresh plugs today trying to clear the spark plug part of the equation.

I had the same problem with a different points motor I fixed up a couple years ago. Is it a sign I should swap in a CRF50 crank and make a CDI setup out of it? Lol... hope not.

arlindsay1992 · 11-24-2007, 12:38 PM

Check the timing. Bad set timing might cause plug fouling. But don't rule out the carburetor. Clean doesn't mean it's adjusted right. If I slap a carburetor from a 67 Mustang on my bike, no matter how clean it is chances are my bike will not run. So make sure that the carburetor is not only clean but adjusted. And it would probably run better with a different carburetor such as a 20mm for top end power, or maybe the carb off of a 70 for more power spread.

50rider340 · 11-24-2007, 01:32 PM

adam, id put the money on it that the points arnt set right. My buddies Z use to do that and it take hours to get it to start. Then we fixed the points and it was a night and day difference. Personally instead of dicking with the points if you got all the parts to make it a CDI go for it. Then if it still does it you know its the carb.

thorwarrior915 · 11-25-2007, 08:59 PM

I put a new plug in it and it seems to be running fine? I'm not going to question it... haha.

and arlindsay... i know you are the ace 15 year old mechanic... but I make my living turning wrenches at the moment so i'm preeeettty sure I know how to clean a carb. I'm suprised you get to clean the carb on your Z without asking your dad's permission!

I guess my problem was trying to get the motor to run good on a used plug. It seems to run overall better since I put the new plug in it and rode it around the yard some to clean it out. I still haven't checked the points... but if it starts and runs good... who cares. If it starts to get worse I will look into it. I just need it to run good enough to sell it anyways....

xr100man · 11-28-2007, 08:41 PM

and arlindsay... i know you are the ace 15 year old mechanic... but I make my living turning wrenches at the moment so i'm preeeettty sure I know how to clean a carb. I'm suprised you get to clean the carb on your Z without asking your dad's permission!

LOL even when I am grounded I can ride/work on my bikes what a pussy!

11-24-2007, 10:15 AM	#1 (permalink)
thorwarrior915 3rd Gear Member Join Date: Dec 2003 Location: Malone, NY Posts: 4,549 My Mood:	'87 Z50R motor fouling plugs? I have a 1987 Z50R 6V points motor with a takegawa stock head 88 kit that keeps fouling plugs. Carb is clean... i'm ruling the carb out of the equation. Is this a sign that the electrical system is weak? When I ground a plug to the head to check for spark it is throwing some huge blue sparks. Doesn't look weak... but I haven't tested it with a voltmeter or anything yet. Why does a little fourstroke foul plugs? I'm assuming its a problem of too much fuel... but with a stock 13mm carb on an 88cc motor... i wouldn't think that would be the issue (stock main jet). I had it running beautifully. Then I went to start it and it wouldn't go. Pulled a plug out of another bike and it burped and ran poorly, then quit. I went and got a couple fresh plugs today trying to clear the spark plug part of the equation. I had the same problem with a different points motor I fixed up a couple years ago. Is it a sign I should swap in a CRF50 crank and make a CDI setup out of it? Lol... hope not.

11-24-2007, 12:38 PM	#2 (permalink)
arlindsay1992 "High Speed Record Guy" Join Date: Mar 2006 Location: Northern Virginia Posts: 4,369	Re: '87 Z50R motor fouling plugs? Check the timing. Bad set timing might cause plug fouling. But don't rule out the carburetor. Clean doesn't mean it's adjusted right. If I slap a carburetor from a 67 Mustang on my bike, no matter how clean it is chances are my bike will not run. So make sure that the carburetor is not only clean but adjusted. And it would probably run better with a different carburetor such as a 20mm for top end power, or maybe the carb off of a 70 for more power spread.

11-24-2007, 01:32 PM	#3 (permalink)
50rider340 3rd Gear Member Join Date: Mar 2004 Location: CT Posts: 3,083 My Mood:	Re: '87 Z50R motor fouling plugs? adam, id put the money on it that the points arnt set right. My buddies Z use to do that and it take hours to get it to start. Then we fixed the points and it was a night and day difference. Personally instead of dicking with the points if you got all the parts to make it a CDI go for it. Then if it still does it you know its the carb.

11-25-2007, 08:59 PM	#4 (permalink)
thorwarrior915 3rd Gear Member Join Date: Dec 2003 Location: Malone, NY Posts: 4,549 My Mood:	Re: '87 Z50R motor fouling plugs? I put a new plug in it and it seems to be running fine? I'm not going to question it... haha. and arlindsay... i know you are the ace 15 year old mechanic... but I make my living turning wrenches at the moment so i'm preeeettty sure I know how to clean a carb. I'm suprised you get to clean the carb on your Z without asking your dad's permission! I guess my problem was trying to get the motor to run good on a used plug. It seems to run overall better since I put the new plug in it and rode it around the yard some to clean it out. I still haven't checked the points... but if it starts and runs good... who cares. If it starts to get worse I will look into it. I just need it to run good enough to sell it anyways....

11-28-2007, 08:41 PM	#5 (permalink)
xr100man 3rd Gear Member Join Date: Feb 2007 Location: Chicago Burbs Posts: 1,129	Re: '87 Z50R motor fouling plugs? and arlindsay... i know you are the ace 15 year old mechanic... but I make my living turning wrenches at the moment so i'm preeeettty sure I know how to clean a carb. I'm suprised you get to clean the carb on your Z without asking your dad's permission! LOL even when I am grounded I can ride/work on my bikes what a pussy!

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