Vintage Dirt Bike Q & A

I need to time my mt250 and not sure how. I have put a cr topend on it but still am using the mt ignition. The timing for the cr is 1.5 btc but the shop manual says the mt is 20 btc thats way different. I guess I gotta time it the way the mt is as thats the ignition I have. Is this timing gonna work right?

What tools do you have to set the timing? There are two basic methods to set the points gap accurately:

1) Feeler gauges and automotive-type timing light

2) Dial indicator and points-opening light

You can also just set the points gap to the middle of the recommended range using feeler gauges, but this is just a guess even with brand-new points, let alone used ones.

I'd suggest 18 degrees BTDC for your bike.

For what it's worth, a CDI ignition from a '75 - '77 CR250 would be a real upgrade. The tiny rotor will allow the motor to rev much quicker, and adjusting the timing is a really easy, set-and-forget type of deal. They pop up on eBay all the time.

Ray

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'74 CR125M (175cc), '75 MR175, '82 RM250Z, '08 YZ250F, '14 Zero FX electric, '14 Zero MX electric, '18 Alta MXR electric