'84 Honda 200ES, Poor Running... Ignition?

[barnett468]

Hello


I just did a quick calculation to determine the approximate distance your full advance mark should be from the F. I based it upon the F mark being 2” from the center of the flywheel which is close enough but again if you had the actual diameter of the flywheel it would change slightly but not enough to make much difference.

30 degrees total advance [which is factory spec] will be 3/4” before the center of the F.

[tvpierce]

Hello tv oierce

Am I off my meds or am I correct in thinking that when I asked you specifically if the timing at isle was factory per manual that you said yes?

I did say that, but it's since occurred to me that if the idle is high, then the ignition should be further advanced to match the higher RPM... correct?

[tvpierce]

Quick update on the carb:

My suspicion was correct. When I originally installed the Chinese carb, the rubber boot between the carb and airbox went on much more difficult than it did on the Keihin carb --the throat on the Chinese carb is larger. I figured it was probably just thicker sidewall material -- perhaps because the aluminum is lower quality. Turns out it's more than that.
Chinese carb on the left, OEM Keihin carb on the right!



The whole carb is MUCH bigger. I forgot to measure the throat of the Keihin carb while I had it off, but you can see it's significantly smaller. Furthermore, the slide chamber that the piston slides in is taller, so the throttle cable never allowed the piston to lower completely... which means the throttle was never allowed to close. (I confirmed this once I had the carb off the trike: the piston was 2-3 mm from being closed.

OEM Keihin carb is back on. The engine now starts perfectly and idles perfectly! Still has the original stumble/bog that I started with (although it's not quite as bad because the engine now has stronger/consistent spark), but at least now that's the only issue it's having.

Ran out of daylight last night, so didn't have a chance to investigate timing. Will do that later today.

[barnett468]

I did say that, but it's since occurred to me that if the idle is high, then the ignition should be further advanced to match the higher RPM... correct?

Hello tvpierce


Not until the engine reaches between 1800 and 2100 RPM


Honda says the F mark SHOULD be in the center of window until the engine reaches between 1800 and 2100 RPM after which point it should begin moving clockwise.

The center of the F mark should move out of the window in a clockwise rotation until 3200-3500 RPM after which point it should stop moving.

The total distance the F should move from the center of the window is approximately 5/8”- 3/4”.

[tvpierce]

OK, I finally figured out what I was doing wrong with my automotive multi-meter, so now I can get an accurate reading using the tach function.

With the engine turning about 1600 rpm, I can't get a reading on the timing marks with the light because oil is violently spewing out the sight hole! The engine doesn't smoke at all, so I don't think it can be blow-by from the rings. Any thoughts on that?

[barnett468]

Hello


Yeah it figures, they only want you to test the timing at idle.

Make sure your oil level isn't too high.

Try removing oil fill cap to help relieve any possible pressure build up and try is again.

Tape a piece of clear kitchen saran wrap etc over the hole.


Will it now idle at 600 rpm?

Is the F in the window at 600 RPM?

[barnett468]

Did you ever do a compression test?

As long as it's above 120 or so it's good enough for now.

[dougspcs]

My manual says to set the ignition timing at 10' +-2' BTDC at an idle of 1400RPM +-100 (600???)

and compression should be 156+-14PSI.. (120???)

What are you using for reference as you are advising people?

[tvpierce]

I didn't measure the RPM down that low, but yes, it idles flawlessly way down to a lumbering idle -- leisurely chugging along.

The lower I set the idle, the worse the oil spewing gets. At mid throttle, it doesn't spew at all.

I never did do a compression check, because I don't have a 12mm adapter for my gauge.

[barnett468]

Hello tvpierce
\
Great, 1 more big problem solved now, what the heck is the timing at idle and when does it start and stop advancing? Are you finally going to tell us or are you trying to beat the other guys record post so you can win a seat of free steak knives.

[barnett468]

The lower I set the idle, the worse the oil spewing gets.

Good, this is how it often is.

[tvpierce]

OK, will try to check timing tonight.

[kb0nly]

The flywheel sits in a oil bath so splattering oil out of that hole is perfectly normal, more at lower speed is also normal because the flywheel isn't flinging the oil off before the hole. As doug posted idle should be about 1400 rpm, i know i have mine just a bit slower than that but plus or minus say 100 rpm doesn't make a big difference.

Thats definitely not the right carb, i have another spare chinese carb and an original on the shelf here, they are exactly the same for bore and slide height. Me thinks the seller you got yours from sold you the wrong replacement.

[tvpierce]

Thats definitely not the right carb, i have another spare chinese carb and an original on the shelf here, they are exactly the same for bore and slide height. Me thinks the seller you got yours from sold you the wrong replacement.

Yeah, I've responded to the seller... waiting to hear back. I know it's not for a 250ES -- that's a completely different style of carb. Wonder if it's for a 200X? Those used the same style of carb. (Not that it matters what it's for... just curious.)

[tvpierce]

Tried again to check timing with the light on the flywheel -- there's no way I can do that. Even with the oil dipstick removed to relieve pressure, as soon as I remove the sight plug, oil is shooting out, completely covering the light with oil. I have to wear glasses to keep from getting oil in my eyes.

I did what my1423 suggested...

Quick extra test.
On the advance mechanism find the magnet end. Black stripe and its magnetic.
Draw a white line on it lining up with the magnet on the bolt side. Outside. Making another timing mark.
Hook up your timing light and see if it is firing with the white line straight at the pulse coil.
Check it on pull starting not running.
Then running Rev it up and down.
If the line stays in one place pointed directly at the pulser coil on all rpms and starting the cdi has no advance.
Mechanical has no bearing on this. Just comparing where the trigger is vs the trip mag.
Because it is firing when the trigger coil is in place.
If it moves not pointing right at the coil then you have electronic advance.
You can also mark on the case idle loaction and high rev spot and measure the degree of change.

Now if your advance is jammed into no advance and your timing marks are 20 off and the pulse is aligned then your timing chain is not properly aligned or the something is funky with the flywheel or key.

That actually worked really slick! I can see that the pulse coil and the magnetic trigger stay in perfect alignment, and I can tell that it's advancing as RPMs rise off idle. I can also see the mechanical advance mechanism moving behind the pulse coil.