1970 yamaha Ct1B 175 enduro with engine running, you turn the ignition switch to lights & the bike starts missing & dies! Could it have a bad lighting coil?

SOURCE: timeing a yamaha 175 enduro

Without the year of the bike I am hampered. Lets assume it is an older bike and has a set of ignition points and not a CDI model.
.
Pull the cover off the shifter side of the engine. Remove the spark plug then turn the flywheel so you can see the points. Oil on them? Dirt, or rust? Next check the main bearing. Do not rotate the flywheel but instead hold the flywheel firmly and lift it up and down, left and right. Was there any movement or was the flywheel rock solid?
.
I am willing to bet that the points were dirty and there was a lot of play in the crank bearings. If so, you will need new crank bearings and seals plus new points and condenser. The engine needs to tear down into about 75 parts in order to replace the bearings. The job requires some special tools to remove the flywheel and clutch, plus a crankcase separator the split the gearbox.
.
This is not a job for the beginner. I suggest you have the shop do the work and also that you spring for 3 more bearings and seals plus a fresh cylinder bore, new piston and rings and a new spark plug. You now have a brand new engine that should run well and last for many years. Please rate this solution. Thanks

SOURCE: Engine cuts of after it runs about 3 or 4 min. If

what kind of machine?

SOURCE: My 81 yamaha enduro is smoking badly

Same happended to me with exactly the same motorcycle... I solved the provblem by replacing the crankshaft oil seal on the rightside of the crankcase. It solved the problem immediatly!

SOURCE: I have a 1972 Yamaha Enduro. When running, the

may be the packing

SOURCE: wiring

Go to the web page link below
http://www.slimduck.com/dt100_175_wiring.html

Hope this helps