Hi i have a 1975 honda cb200..new plugs,points and timing set..new carb kits inc needles.tried different coil and condenser....great untill engine up to temp..then flat spot off tickover......also black smoke if revved hard...please help...kind regards john

Chances are it is the ignition box on the fender. It controls the ground signal to the coil and the timing.
If you can duplicate the problem and get it to "not start" you could test the box. Otherwise it may be tough to troubleshoot.
There's a chance something is going on with the pickup coil in the distributor too.

battery up to parr? try new sparkplug,does this bike have new igniter pac,?check voltage at coil,etc at coil,points..are points grounded?

Seems that the crank/timing settings needs a closerr look than to feel that the carb is faulty.The engine is becoming rougher because the firing angle is changed. I also doubt that the carb /jet kit be replaced back with the original as the new jet is not matching.
Now start the engine and set up idle to more than minimum so that the vehicle does not stall but is somewhat smooth. Now try to advance/****** the timing and notice if the engine becomes smoother irrespective of the TDC settings. If so set to the best level and bring down the Idle , do not reduce off air but check the mixture at the exhaust to have this done all over.
Somewhere in the new change a point has been missed..

1975?? it has a carb and points ,check the points gap first if that doesnt work then its carb strip and clean

If there is no spark your points are probably dirty or just grounded out. Try a new points and condenser set. Install the points carefully so the new set does not ground. I assume you already tried new spark plugs and spark plug caps.

Sounds like that cylinder is running very lean, which causes high heat. If you have multi carbs, get them synchronized right away, the high heat can ruin a cylinder/burn a valve.

The CB200 may be able to do better when new however being only 200CC and the age of the machine this may be its best. You could check the compression to see what you have; if these are lower there would be some lose of power there. Also the carbs may need a once over, this too may get you more. However I would not expect to cruise at 65MPH with a 200CC, she'd be running pretty hard. The redline may not be unitil 9300RPM however the engine lacks the torque/power to push it beyond where you're at now, the 9300RPM may be used to get you there. In theory if you could take it out in max. gear to 9300RPM the bike would do @ 110MPH; many 750CC bikes cannot do this.
Great bike though, should treat you well, enjoy the ride and the gas mileage...
Tom

I had the same problem - actually more than one problem:
1) Floats in the carburetor bowl (at the bottom of the carb) are getting stuck. Remove the carb; carefully disassemble the bowl & float assembly (pay attention to gasket orientation and don't lose the needle valve that the float-tab presses on!); use a carb cleaner from AutoZone or similar, and a toothbrush to clean all the parts. If carb is not too dirty, leave the jets and mixture-adjust screws alone (otherwise will have to re-adjust later).

2) Overflow tube is plugged (hence fuel in the cylinder instead of on the ground). Clean both ends of the brass-looking tube from inside and outside the carb bowl. Make sure you can blow through it or it is still plugged. Toothbrush and carb cleaner should do the trick. Replace the short flexible tubing that connects to the overflow on the outside of the bowl - transparent polyurethane tubing is less than $1 per foot at your local ATV/motorcycle shop.

3) Air Vent tube is plugged. Same thing as the Overflow tube but mounted higher up in the carb (not in the bowl). Clean it the same way and replace the flex tubing with another short piece of polyurethane.

4) Make sure the float-tab and needle-valve move smoothly. Mine was catching and getting stuck so I carefully "polished" the face of the tab with 400-grit emery paper, and then made sure to clean the area from grit. Smooth as a hot knife through butter now.

5) Set the float level by CAREFULLY bending the tab that pushes on the needle valve. On my 1981 175MX, float height spec is 21mm when just making contact with the needle. Yours may be different though.

6) Reassemble the carb after making sure all dirt and debris are gone. Use a new bowl gasket or at least put a good gasket-sealer compound on the old gasket. Attach the short lengths of transparent polyurethane tubing to the Overflow and Air Vent. When installing the carb, the Air Vent tube should just be 2" long and point out to the side; the Overflow tube should route through the frame near the swing-arm and point down to the ground.

7) MAKE SURE the Oil Feed tube coming from the AutoLube oil pump is connected to the carb (brass-looking fitting toward the cylinder-end). I replaced mine with transparent polyurethane tubing (different size than the Air Vent and Overflow), so now I can see that oil is being presented to the carb!

8) If the carb was nasty-dirty, you may need a new air filter. Mine was disintegrating. I recommend also putting an in-line fuel filter between the petcock and the carb, again using short lengths of TRANSPARENT polyurethane tubing (so you can see that fuel is flowing). You may also need to adjust & prime the AutoLube oil pump.

I highly recommend getting a Clymer manual (check eBay) which shows all these procedures and gives you the right specs for float height, etc. based on your model / year.

Hi

I suppose is 4 stroke engine.Before adjusting the breaker points gap at .020 check if the breaker points are burned.Also check the condenser(change it).Change the spark plug with a new one with the same heat range.The plug gap is .030.

best regards savumihai71