'75 CB200 engine spins backwards during ignition -- won't start + video.

tnahvu, did you originally check the ignition timing with a small test light that went on when you turned the motor over by hand slowly?

I'd recommend checking the cam timing first just to confirm that it's correct and then check the ignition timing after you put the stator and side cover back on and remove just the outer round cover.
 
'75 CB200 engine spins backwards during ignition -- won't start + video.

yes, i did check with the 12v small bulb so that it lights at F preinstallation. the timing was spot-on.

and the engine cover was removes briefly for the video. i've been tryin to work with the bike with omly the stator cover removed.

thanks
 
Please do not run that motor without the side cover on... And, since you have, please check your oil level and make sure its full.
 
If it is switching at the F mark ir should fire up OK but would be flat as a tack at higher revs if the mechanical advance were no longer in place. BUt it would not spit back with that timing, so that suggests something else.

After you check that at TDC one set of valves is slightly open and the other pair is completely closed, please check the timing again with that small 12v timing light and let us know what you see.

You mentioned that it was checked "pre-installation". What did you mean by that? I check timing AFTER I have installed parts. You must mean something different.
 
'75 CB200 engine spins backwards during ignition -- won't start + video.

i just meant that timing was good before i began on this most recent project.

but the bike still couldn't get pass 7500rpm in fifth and i read that some people w/ cb175/200 got success with higher revs after the electronic ignition installation. i wanted to do it right, thus, bought the dyna coil along with it.

will definitely check valves gap and timing when i have time and report.

how does the cam timing procesure differ from the ignition test? pardon my ignorance but i couldn't find anything in the manual about setting the cam-timing.

thanks again
 
The stock cb200 has a fixed cam sprocket and can't be advanced or retarded. It is bolted in place on that model. You can mill slots in the sprocket to achieve this, but is tedious work.
Kev
 
Kev is right. The cam timing is not readily adjustable.

The camshaft is timed so that the valves open and close at very specific points in the cycle. The points cam (or rotor in this case) sit on the end of the camshaft. If the camshaft is one or more teeth off, it is still possible to get the ignition timing set by rotating the points mounting plate far enough to compensate.

Normally the camshaft stays in the fixed relationship to the crankshaft that it was set at when the motor was built. In your case it is possible that the cam chain might have jumped a couple of teeth when the adjuster was loose. Let's hope that is not an issue, but it's worth checking.

Then you can reset the ignition timing so that it fires at the advance marks when it's fully advanced (if it still has the weights and springs behind that plate)

Hope that's clearer.
 
Is anyone with a 200 willing to make a video to explain all that? Sometimes seeing the explaination is better than reading it. Could also be helpfull to others in the future as the popularity of the bikes is skyrocketing.
 
It's on P22 of the Factory Service manual. If I could remember where it was downloaded from, I'd point you in that direction.

There's a CB200 motor here that I'd be happy to pull apart if someone is good with a video camera and editing software.

There are simple ways to check that the camshaft is not mikes out. It's not rocket science.

At TDC when the pistons are as high as they can go, the T mark on the alternator rotor should be in line with the pointer mounted to the stator at the 10 o'clock position. At that point, one cylinder should have just passed the point at which it fires, so both valves will be closed. The other cylinder will be at "overlap" where both valves are open. The exhaust will be almost closed and the intake will just have started to open.

The way to see that, is to remove the plugs and all 4 valve inspection caps and rotate the motor forwards while you watch the valves move. Watch the intake valve on the side nearest you and as it starts to close you can see the rocker arm rising. When It's almost closed, check the rotor and it should be approaching TDC T mark. Turn it over a few times to see what's happening.

There is only one point where both valves are open at the same time and that's in the period of around 20 degrees before TDC to 20 degrees after. Keep an eye on the rotor as you turn it and determine if the valves are indeed both open at the same time at TDC.

A four stroke takes two complete revolutions to go through all 4 strokes so one time it's at TDC, the valves are both slightly open and the next time round, both are closed. You can check that cylinder by grabbing the rocker arm and see if it moves slightly. 180 degree crank motors have one up and one down so it's harder to do this crude check on them but the principle is the same.

All we are trying to do is to get a quick idea whether the cam chain has jumped a tooth or more. It's no substitute for accurately timing teh cam, but it should tell us if it's miles out.

Another giveway on a CB200 is that the points cam is located by a small pin pressed into the cam. At TDC that pin should point straight up. If it points straight down, rotate the engine through another full 360 degree rotation. If that pin is straight up and the valves seem to be timed OK using the TDC method, I just talked about, then the camshaft is in the right place and we can all relax.
 
'75 CB200 engine spins backwards during ignition -- won't start + video.

had some time during lunch today, so...

at TDC, T mark on the alternator, the pin on the camshaft was at 12 o'clock relevant to the lean of the engine--as oppose to the natural horizon. at least to my naked eyes, it looked like 12 o'clock.

so that's good news, i guess, right?

also got the little 12v bulb to lit at the F full advance mark, the left of the two parallel lines. will fill it up with oil and give it a go tomorrow.

thanks again all
 
When turning the crank and having a bulb attached to ground and then the points, the bulb should come on EXACTLY as the F mark on the rotor passes the timing mark. The markings for advance are for use with a strobe light after the bike is running.
 
Hold on a moment. The T mark and 12 o'clock pin is good.

What did you mean about the F mark to the LEFT of the two advance marks? Looking at teh rotor there should be a T mark and at 5 - 10 degrees to the left of that (counterclockwise) there's the F (fire) mark. 30 - 40 degrees further left are two more marks for full advance. There should be no more marks.


Normally that timing light should light up when the rotor is at the F mark and when it's running it should advance to the pair of marks. There should be no other F mark further around. If the timing is "FIXED" ie no advance retard, the timing should be set at teh advance marks but only if it's fixed.

If you are not sure if your bike still has the advance, grab the rotor and try to twist it to the right. If it moves against spring pressure, the advance mechanism is still there and you time it at the F mark.
 
'75 CB200 engine spins backwards during ignition -- won't start + video.

my understanding is that i have to set it at the full advance mark, the parallel lines, since this pertronix unit does not have an "electronic advance AFIK".
 
Correct. Some Pertronix kits come with a solid shaft to replace the points cam and all the Advance-retard mechanism. If that is what you have, then the timing should be fixed between the two advance marks.

The only issue is that fully advanced it will tend to fire back and may bite if you don't kick it hard enough to keep it moving forwards. We bump start our race bikes with fixed ignition, so there is no chance of it kicking back but that's a bit touchy on a street bike.

That's why Les Barker says that his system is race only.

Is that what you have?
 
Yep. I got the pertronix and dyna elsewhere with Les's camshaft adapter. i plan to use the electric starter for my bike.


as for racing goes, i plan to seriously look into it once i get a firmer grasp on bike mechanic and have more riding experiences. this will be a commute bike for me, as well. i got half the day off tomorrow to tackle the bike and hopefully get it in riding condition and post an update.


thanks again
 
Good. With that set up the timing should be set at full advance and it will tend to kick back.

I would use the kicksdatert and alwys give it a firm kick don't tickle it or it will tend to bite back. Fotunately it's a small bike and its bark is worse than its bite.

So far we have managed to confirm that your ignition is always fully advanced and that the camshaft is probably in the right place and taht teh motor is running the right way.

Now we need to get you up and running.
 
'75 CB200 engine spins backwards during ignition -- won't start + video.

woooooo weeee!!!!!!!!!!! the beast lives!!!

fill her up with oil, whispered in her ears, prayers and offerings to the buddha on the altar, flip the switch, pushed the start button and VROOOOOOOMMMMMM!

still have to properly time with the strobe later with the stator cover removed and adjust the carbs as the revs doesn't back down properly--too slow.

got the needle clip one notch near the bottom as she won't even start if it's above the mid notch. got the air screws -- and not the big idle screws this time:D -- 4 turns out. this is nate's set-up, 74cb200, who also had the dyna coil, pertronix unit.amd mikuni vm20s.

but damn it feels good to have the wind in the face and engine growl in the ears again.

i plan to make a full detailed thread after i'm done with the bike so others may use it for references in the future. many thanks to teazer, sonreir, sallgoodguy and everyone for the comments and tips!
 
quick update


got it timed with the strobe finally. here's the video and some photos of it still under operation


IMG 0118


IMG_0110.JPG

IMG_0113.JPG





will take it out first thing tomorrow morning for a test run. can't wait!!


**the car and house are not mine. just the bicycles and t-shirt rag on the grass...:(
 
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