Help needed, zongshen wont fire, good spark&fuel

[SpudRider]

I bought this compression test at Harbor Freight; it does a great job.

http://www.harborfreight.com/quick-c...ter-95187.html

Use a 20% off coupon, and you can buy it for $24.

[b44]

Ok great ill order one tonight,in the meantime any suggestions i could try till parts turn up? Shes looking sad & orphaned
Cheers

[Mudflap]

To get some idea on compression I remove the plug, hold finger in hole as tight as you can, open throttle, crank engine. If I'm unable to stop air from escaping, it should have enough compression to start.

Low compression can be caused by something as simple as a flake of carbon stuck between the valve and seat.

[b44]

Does timing look correct to you mudflap?

[zingshoen]

not sure what the problem is, but take heart! i have this kinda motor and had to go over the whole thing a few times, until she would fire up. from what i remember, there was no real mark on the flywheel for TDC for starters, so i ground a mark on the flywheel and set the valves. after chasing my tail for a bit, she started up, but ran awful, until i cleaned the carbie which was new, set it up for stock, left the air filter off, which for some reason had blocked the venturis. after that it was smooth sailing and it is a fantastic motor - so from my experience, if you get fuel and a fat spark, i still had to set up the carbie properly.
the crf230 manual was helpful, i can dig up the specs, if u don t have them, but check thumpertalk, they had a pdf AFAIK.

[b44]

Yup thanks,i inspected the carb today pretty much new so float was fine,everything seemed normal,i did notice a strange outlet on the inlet manifold, i think if it was the carby it would still fire up momentarily with start fuel, im getting nothing,come to think of it compression is on a avarage to weak side, so might take off rocker cover & have a look.closest thing to manual i have is my old xr600 one not really that helpful as its a rfvc, so you rekon Crf230? I read somewhat that they are cb250 clone?

[Mudflap]

I'm not sure how they work the cam timing marks on that particular engine. Usually there is a mark at the top of the cam cover that aligns with a mark on the cam sprocket but I don't see that in your pics. Someone more familiar with that engine would know.

You mentioned a strange outlet on the intake manifold. Is it something a small rubber hose would attach to? Can you poke a wire through the hole into the manifold? Often times vacuum from the intake manifold is used to operate a vacuum petcock. If the port is not plugged it'll be a big air leak which could stop the engine from running.

Just noticed your engine is equipped for exhaust port air injection. It works by using vacuum from the intake tube to actuate a valve in that system (which your bike doesn't have). That is probably what the port in the intake is for. It should be plugged.

[zingshoen]

as HB noted above, yours has a displacement of 233 cc, i think more similar to cf 230s, just for reference, but still same motor design. check actual cc for honda 250, should be 249 cc i think.

[b44]

Ok so I decided that the compression was low,so whipped the head off only to find frame was in the way , so engine is out, everything looks in order, at tdc piston is up, valves are at 7 - 5 o'clock, found a timing mark on top of rocker cover, all seems ok cant get my head around why compression is so low,tested stator for constant power its ok, valves seem to be seated ok

[zingshoen]

Mate, sorry to hear the motor isn t going. I ve checked and I have the same motor. Compression problem on new motor? Not sure...though my motor wouldn t run properly, valves set acccording to what not...separate problems in all systems...had to go over everything methodically, but that was a while ago now. below some of my notes copied from the inti, which helped me at the time...hope sth helps, please ignore if you ve covered what s mentioned - i found that after working out all the details she rocked and still does :-) it may be a problem in the electrical system, a bad earth - would be worth checking the values of the electrical components (i did all that, applying loctite fixes, routing overly tight cables) and continuity with your multimeter.


VALVES
OHC motor, not pushrods.
According to Honda dealer in Japan http://www.ride-inc.net/file/32/data.pdf
MD33 (65.5mm x 66.2 mm) IN/EX = 0.1mm (0.004 inches)



To check the valve clearance, the piston must be top dead center (TDC) on the compression stroke. Use a 14 mm socket to rotate the crankshaft counterclockwise (Figure 12) until you see the "T" through the timing hole and the line to the left of the "T" is aligned with the index notch in the timing hole.
At this point, the piston is at TDC of either the compression stroke or the exhaust stroke. However, you need to make sure it's the compression stroke. One clue is that, as you approach the "T" mark on the compression stroke, you'll feel greater resistance in rotating the crankshaft (due to the compression).


If the engine is at TDC in the compression stroke, there will be some play in both the intake and exhaust rocker arms. (The adjusting screw can be moved up and down slightly.) But if the engine is at TDC in the exhaust stroke, there will not be any play in the rocker arms.
Plug

Manual says DPR8EA (extended tip plug), D8EA may run cold, gap should be 0.8-0.9 mm.
Honda230+clones have the NGK DPR8EA-9 sparkplug
The spark plug gap should be 0.6mm-0.7mm (0.02-0.03in). Normally it's ok with new spark plugs.

[b44]

Hi mate appreciate the help, i think i may have found posible culprit,while engine is half part ive checked the stator w meter, ive got a short on one of the wires (green one) im hoping this is it, ???now the thing is do i bite the bullet and get entire electrical system $110 -120,,or just the magneto, around $40, is it entirely possible for this to cause a weak spark? Hence no detonation? Everything else checks out, yup your right about compression on a new bike,i have a 1980 xr200 thats been absolutely thrashed to hell & back and still runs with low compression, loose tappets & no airfliter, snapped frame,half exhaust pipe,why i chose this bike those engines are bullet proof,
Hopefully this is it, as its pretty easy just to buy complete brand new engine for under $600 , but then i don't learn anything
Also i have read this vacuum petcock valve from inlet manifold to petcock has caused drama with alot of bikes, this could be drama as ive ordered a generic petcock jobby off ebay,original is broken
Double checked valve clearances everything checks out,fingers crossed

[zingshoen]

yes, but if you get a new engine it may still need help.

i would just get what i need, maybe wire can be fixed with soldering? you ll need to get into the electrical system and make sure all components are good and do what you want them to do. below some of the notes i copied form other authors, use with a grain of salt. get a wiring diagram for your bike or make one up. it s easy once you get your head around it. make sure u have good grounds, from neg batt terminal to frame, use thick wire. i underlined the relevant sections below. good luck, i m going to hit the sack!

Zongshen 230 Electrics
The red wire and the yellow wire came from the windings on the stator. These will need to be hooked to a rectifier/voltage regulator. The green/white wire is a ground. I grounded it to the block with my other grounds.
The blue/white wire came from the pulse generator magneto (for lack of better term), and the black/red wire came from the body of the magneto.
Having extracted the original connectors for the CDI from the rat's nest, I determined that the black/red wire needed to be connected to the lower pin of the 2-pin connector on the CDI. The upper pin is what you short to ground for a kill switch.
Then I located the 4-pin connector for the CDI. Turns out only three pins are used. Upper left is pulse from the magneto (blue/white), upper right is coil output, and lower right is a ground.
+++++++++++
Three yellow wires to the regulator is standard fare for a three phase battery charging scheme. Blue/White (CDI timing trigger) and Green/White (trigger return) are standard colors for the CDI trigger function. If your CDI is DC powered then that's all the wires needed out of the stator. If your CDI is AC powered then we need another wire (usually black/red) coming out the stator as well

Just to verify that the blue/white and green white go to the timing pickup coil inside the stator, take a meter and set it to measure resistance on the 2K ohm scale (2000 ohms). Measure the resistance between the blue/white and green/white wires into the engine. What do you measure?
####
The green wire getting very hot tells me that there is a grounding issue somewhere else causing the motor to ground through the stator ground wire (the green one).
The first thing I would double check is the ground circuit on the machine. The negative side of the battery should go to a ground lug on the frame, from that same point there should be another ground wire running to the motor, usually connected under a valve cover bolt. Make sure these connecions are clean and tight. Now, if those are correct, then I would suspect that there is a problem with the new stator.
#############
ground wire to emgine case lower rear, 10mm wire!
This is a very important connection as all the heavy currents to the starter motor, from the alternator and others go through this. It's important that it be kept tight and corrosion-free to ensure a low resistance connection.
An important piece of advice to add is that the ground lug should go on the bottom half of the case. Since this is the return for the starter motor (which only has a positive supplied to it), you should not allow the return current to take a path that involves going through the upper half of the case and hence all the sealing goo used to put the cases together.

The idea is to find if there's a voltage drop along the earth cable and its connections. By measuring the battery voltage first you have a reference figure to aim at.

You should get more or less the same when you move the negative meter lead on to the crankcase. If you get more than around 0.1 volt drop there's a problem in the cable path.

You could also measure resistance with the meter in the low ohms range as you suggest. Don't know what sort of resistance figure is aceptable for a good joint though.

+++++++++++
The Ignition Power winding and Timing/Trigger resistances (200 ohms and 124 ohms) sound like they are in the realm of possibly being correct. It varies some from stator design to stator design. All three windings in the stator (the other being the battery charge winding) are just coils of wire. The resistance of each winding is set by the total length of wire used to make the coil and the gauge of wire used.

The two things that can go wrong with the stator windings are:
1) A wire breaks (and the winding becomes open)
2) A wire shorts to another wire (or to ground)

You've eliminated possibility #1 already. Shorts in any of the stator windings will drastically affect the output voltage of that winding. The best way to test the stator for shorts is to measure the stator output voltages while cranking. To do this the meter must be set to AC volts. Also, (important) the ignition power winding (blk/red) must be disconnected from the CDI when making these measurements or the measured results are meaningless.

The ignition power winding should read 80 volts AC or so to engine ground while cranking. The ignition timing/trigger line should read 0.3 volts AC to engine ground. The latter voltage is actually a complicated waveform what meters don't measure well, so it may vary a bit from meter to meter, but you should measure something other than zero volts.

the yellow wire coming out of the reg/rec never has its own power, it just "T's" into the yellow wire that comes from the engine's stator wire, that then goes to the headlight dimmer switch. it takes excess voltage and delivers it back to ground. thus the regulator part of the regulator/rectifier.

[bogieboy]

a t the current state your engine is in its a wise idea to pull the cylinder jug off to veryfy that you don't have weak/stuck rings causei g copression issues... I would also inspect the cumbustion chamber/valves for excess carbon while the head is off... but what would a little old tractor mechanic know about dirt bikes...LOL ;-)

[b44]

Haha yeah mate ive come to that exact conclusion aswell ill start tear down soon, its all just not adding up,on my attempt at drag starting it with my ute i did hear odd sound coming from valves almost tapping sound, its Strange for a bike that hasn't even been run in yet to have knackered valves, how ever at least ill have a good chance at sorting it properly fingers crossed, i don't think its electrical now as its throwing good spark
Ive ordered crf230 manual & compression tester off fleabay

In the meantime something off topic has anyone modified exhaust/inner baffles for these china bikes, be nice to have someone kind of sound coming from the exhaust & just looks a bit pansy
Appreciate the help


Cheers

[Azhule]

Several people have drilled out the rivets around the muffler to start gutting the inside of the exhaust... it's usually a lot of work if you don't have a 'drill press'

But I have no clue how to open up and gut your current exhaust from that pic, would need a side/top/bottom view... rarely they give you some kind of hex/Allen wrench style bolt that doesn't need drilling out, doubt it would be on any china bike tho