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Why don't my points open? TY250


Baby
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Hi, first post, other than the introductory post in the other forum. I am in the process of getting my TY250 in good running order. In the process of checking the timing and the points gap, I notice that the points don't seem to open at all, no matter how they are adjusted. What am I missing?

The bike starts on the first or second kick and runs fine up to half throttle. (I just installed a new carb and ditched the autolube pump, so I have some smoothing out to do. But I wanted to dial in the ignition before I go too far messing with jetting.) Mystified.

 

IMG-5547.JPG

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21 minutes ago, b40rt said:

Are you checking with the flywheel fitted ?

Thanks! I tried turning the shaft by hand without the flywheel and then with the flywheel seated but not tightened in. Does the flywheel need to be fully installed?

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15 minutes ago, Baby said:

Thanks! I tried turning the shaft by hand without the flywheel and then with the flywheel seated but not tightened in. Does the flywheel need to be fully installed?

The "cam" is the centre of th flywheel, so it does need to be fully home, but not necessarily tightened. (always wondered what nobody makes a dummy centre)

 

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24 minutes ago, b40rt said:

The "cam" is the centre of th flywheel, so it does need to be fully home, but not necessarily tightened. (always wondered what nobody makes a dummy centre)

 

I just gave a damaged TY175 flywheel to a friend because he wanted one to cut off the rest to leave the hub so he could do just that.

However I don't think it would be as accurate as using the cam that it is being run with because there are bound to be slight differences between them.

Also I prefer to use a timing mark on the flywheel rim rather than piston position.

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  • 5 months later...
On 12/20/2020 at 2:11 PM, Baby said:

Hi, first post, other than the introductory post in the other forum. I am in the process of getting my TY250 in good running order. In the process of checking the timing and the points gap, I notice that the points don't seem to open at all, no matter how they are adjusted. What am I missing?

The bike starts on the first or second kick and runs fine up to half throttle. (I just installed a new carb and ditched the autolube pump, so I have some smoothing out to do. But I wanted to dial in the ignition before I go too far messing with jetting.) Mystified.

 

IMG-5547.JPG

The points won't open without the flywheel cam to ride on.  You have to be careful when re- installing the flywheel as the cam can get caught on the points arm and bend it.  I use a small piece of plastic with a string on it to make the points rise above the cam until the flywheel is back on the shaft and the keyway is lined up and installed.  Then I pull on the string and the spring in the points drops the points arm back down on the cam

IMG_0764.JPG

IMG_0765 (1).JPG

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