I will be installing new points and condensor in my ty250a to try to cure some of it's ills. I have the origonal service manual, is it necessary to remove the head and use a dial indicator for the true before tdc readings or can they be replaced and set with a feeler gauge to specs.

It probably a good idea to remove the head and clean the carbon off but do you really have to pull the cylinder and clean the ring grooves etc as the manual recommend yearly? If so can form a gasket work for the cylinder base or must one use a oem gasket?

You don't say what the "ills' are ? The TY250A is very simple as it has a fixed stator plate and therefore does not require setting any timing. If you are fitting new points then make sure the surfaces are clean and not the teflon coated style. Set to 15 thou. use the correct plug, NGK B7ES and set to around 22 thou. The engine may sound a bit rattly but that would be normal so taking the head and jug off it is not normally necessary unless you are going for a rebore. Most of your problems will be ignition or carb related. I would replace your main hot wire from the stator if you are changing the condenser, check the condition of your plug wire and cap and replace if required. Old carbs can be difficult to get running smoothly again especially if someone has changed all the jetting. You might be better starting with a new Mikuni VM26 correctly set up at around 150-155 main and 30-35 pilot.

Tony

The main thing I am hoping to cure is during a event is I stay out of heavy throttle which I normally never need all is well but between sections if I open it up and go through the gears it will bog down and quit sometimes it starts right back up but then I have to "nurse" the throttle back up and it will be O.K. as long as I don't have a steep hill to climb. I always keep a couple plugs along and that helps for awhile. This was a barn find and I have no idea what shape or how old the points and condensor are. I have a new B&J Mikuni set up on it and Boyseen reeds from the same. New carb filter, oem petcock and open vent for the fuel cap. I did notice the last time while replacing the plug that the boot has a split in it so I will replace that as well. I do use the b7es plugs at 22

For the most part you seem to have the carb side solved so a good look at the ignition should do it. I would fancy from what you say the points are out there at around 18-20 through wear and may well, like roses, have "black spot" and the condenser is about done! Tidy up the plug cap and cut back to bright wiring before fitting the cap. If this doesn't solve the problem, and assuming the oil system is off and the base of the cyclinder plugged then decoke the exhaust system.

Tony

Is there any product here in the states that works well for decoking? I have read of "caustic soda" but not sure where I can get it or if there is a brand name for it? Would a hot tank at a machine shop work? I have not found a d.y.i. on this on your blog.

Thanks!