Motorcycle Repair: CB200T Engine miss, plug caps, compression stroke

Question
Hi, I'm trying to help out my son who just bought his first bike. He bought a 1977 Hond CB200T that's in really nice shape but there is this engine miss and power loss I can't figure out and I'm at the end of my ability. The bike fires up great, actually idels cold just fine, but when it warms up or you try to get it up to 40 mph it has a miss in it. We cleaned out the gas tank last weekend, the previous owner said he "redid" the carbs, we put new plug in it, checked the gap on the pints and they look good...I'm thinking maybe it's the coil? Curious what you might think. Are these coils intercahngeabl eiwht any other model to your knowledge because I'm not finding a lor of parts for this model?

Thank you

Answer
Ray, It may be more or less complicated than you think...

First, be sure that the compression is good on both sides, valves adjusted at .002" cold on compression stroke and the timing is set to open the points at the F mark alignment of the rotor/flywheel and the stator markings.

Now, the one thing overlooked is that there is a mechanical spark advancer that lurks behind the point plate! When they seize up/gum up, then you don't get spark advance, as you should. This will show up at part throttle and higher speeds. Check it for smooth advance/retard after you pull the point plate. When you reinstall the points, the gap should be at .014" widest gap, then move the point plate around to where the points just open at the F mark.

Check the spark plug caps for matching resistance values... around 5k ohms. Be sure they are screwed tightly on the ends of the wires and that the rubber sealing boots are all tight and snug on the wires and cap.

"Redid" the carbs could be anything. If he used aftermarket carb kits the jets may be wrong. The carb slides are LEFT AND RIGHT sided, so be sure that they are not in backwards! These bikes shouldn't fire up cold w/o choke, unless you are in a warm climate. Check the float levels 21.0mm, with the float tang just barely closing the float valve needle into the seat. 1 1/4 turns out on the mixture screws.

Honda coils SELDOM fail and people waste a lot of money on them, only to find that that is not the problem! And no refund on electrical parts at the stores. Do be sure that the point faces are clean. After you have the points and timing adjusted, watch the points open and close. If there is heavy arcing at the points, then the condenser is either bad or the lead isn't tight.

Honda CB200s are the last in the line of the small twins, starting with CB/CL/SL175s. A lot of the electrical bits should fit, including the 12v twin lead coils, if that turns out to be the issue.... 200s were only built for 3 years and not wildly popular, so parts are scarce. The CL200 was only a one year model...

Bill Silver