1980 Yamaha yz 250

Zaloznikvti
Edited Date/Time 8/7/2017 10:41am
Hello! I need some help!
I have Air cooled YZ 250 1980 engine have new cylnder bore,New piston,new NGK B9EG.But i try engine start not go.Ignition coil have from YZ 250 1988..Gasoline come in cylinder..and it is have spark and ignition timing is ok...I think is something wrong with CDI unit....And for end i say sory my english not really good..Smile






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MaxPower
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MaxPower 4/29/2017 5:30pm
4/29/2017 5:30pm
You are going to have to reword that clearer my friend. I don't understand what you're asking
Sofiedog
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Sofiedog 5/1/2017 10:13am
5/1/2017 10:13am
MaxPower wrote:
You are going to have to reword that clearer my friend. I don't understand what you're asking
Sounds like: "Bike won't start. Have new top end and plug. Engine is getting fuel and spark. Timing looks correct. Could something be wrong with my CDI unit?"
Zaloznikvti 5/1/2017 12:31pm
5/1/2017 12:31pm
Yes bike won't start. Yes, I suspect CDI unit...But I have a good spark..interesting...I checked as well as all the wires.
Zaloznikvti 5/1/2017 12:55pm
5/1/2017 12:55pm
But this thing on picture is in bad condition...Could be here, something goes wrong ..

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MaxPower
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MaxPower 5/1/2017 7:23pm
5/1/2017 7:23pm
I wasn't being sarcastic, I really didn't understand
Did the bike run before you changed the top end?
It's only my opinion but I don't think the bare spot on the stator is at fault
Try kicking the bike over in a dark garage. Perhaps you could see if something is sparking in the stator area.
Is the plug very wet ? Could there be a large amount of assembly oil in the bottom end? Did you try bump starting it?
Zaloznikvti 5/2/2017 2:39am
5/2/2017 2:39am
This engine I buy by parts dont no it is run before or not...Yeah plug is wet..Just i try start with kickstarter...Upload some video how does it look...
mxrose3
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mxrose3 5/2/2017 1:24pm
5/2/2017 1:24pm
You should be able to test that stator with an ohm meter. The service manual has the specifications on what they should read.
MaxPower
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MaxPower 5/2/2017 7:42pm
5/2/2017 7:42pm
Try push starting. Could be loaded up
Zaloznikvti 5/3/2017 11:12am
5/3/2017 11:12am
Today i check stator like that It shows me 490Ω ...This picture is just symbolic.

mxrose3
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mxrose3 5/3/2017 2:33pm
5/3/2017 2:33pm
Zaloznikvti wrote:
Today i check stator like that It shows me 490Ω ...This picture is just symbolic.[img]https://p.vitalmx.com/photos/forums/2017/05/03/192370/s1200_13329123_454878867969996_1972856473_n.jpg[/img]
Today i check stator like that It shows me 490Ω ...This picture is just symbolic.

There should be two resistances that you have to check. If I remember correctly, one is a 'source' coil, and the other is a 'pickup' coil.
Zaloznikvti 5/4/2017 12:52pm
5/4/2017 12:52pm Edited Date/Time 5/4/2017 4:04pm
Yes..also check source' coil and pickup' coil...and how i check CDI unit..or i throw it in the trash and i buy new..Smile Still I am thinking if this cdi, I have the right for this engine and ignition..
mxrose3
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mxrose3 5/4/2017 8:08pm
5/4/2017 8:08pm
yeah, there is no way to test the CDI. You can test the resistance of the spark plug coil with an ohm meter also.
If it also tests good, double-check all the wiring, then replace the CDI.
Zaloznikvti 5/13/2017 11:09am
5/13/2017 11:09am
Today i start bike is running about 5 second but not replace CDI unit yet...
Zaloznikvti 7/18/2017 7:58am
7/18/2017 7:58am Edited Date/Time 7/18/2017 9:08am
Today i find new problem..I think is that problem for bike dont wont start running..It also leaked gasoline.here.



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