Potentially good improv with the radiator key. I’ll keep a lookout for a tiny one, though I’d guess there maybe arent that many radiators on The ROC.
Re The Troll I had those where the car was too, one of whom may have dropped dime on me with the cops, since I was taking up a parking spot.
Working at GF’s place so on suffrance, and can only make noise about 13.00 to 14.30. Still more convenient situation than car, which was 10 mins away from my tools, but I preferred working on the car. Hardly ever fell over.
Started OK a few times but wouldnt idle right, and then died electrically, so more fiddling required.
Although this is an old bike its still undesirably modern compared to the car, since ignition, rectification and voltage regulation are all "black boxes"with limited scope for checking.
I was starting it with the air filter box off, so I could watch the carb slider, but since I’ve seen it alleged you shouldn’t do that, Ill try putting it back on again.
Carb accelerator pump diaphragm looked a bit knackered but that shouldn’t be a problem yet.
Fixed the electrics (bad connection) though ignition wasn’t affected anyway so it would still kick start.
Seemed to start a bit more easily with air filter on, and I could keep it running for a bit longer on the throttle, but it still wouldn’t idle on any settings (of air bleed screw and throttle stop) that I tried.
I suppose I’ll have to clean the carb again, a bit more aggressively this time. Probably have to risk poking something through the jets.
Before you go poking things in holes that are not for poking, try picking up a small bottle of the fuel additive jet cleaner.
You can pick it up from all petrol stations about 70nt, leave them sitting in it overnight and if it help add the cleaner to a full tank of petrol when you get it running.
My carb cleaning regime involves alternating boiling with (automatic) laundry detergent, squirting with a hypodermic syringe, soaking/squirting with brake fluid, soaking in carb cleaner, soaking/squirting with ethanol, soaking/squirting with acetone (When I can get it. Acetone is harder to find lately. ) IIRC acetone kills the syringe so tends to be the last resort.
I generally avoid sticking things (fine copper wire, nylon bristle as first tries) in jets, but in extremis have used a fine hypodermic needle, which is both hard and sharp, so likely to be damaging, but also likely to shift stuff.
I dont have compressed air but a hypodermic is a pretty good substitute.
Started leaking all of a sudden. Upside down with the float bowl off, and thus the weight of the floats pressing on the fuel shut-off valve, holds a realistic head of fuel pressure.
Right way up with a clear drain tube acting as a sight glass and the drain tap open, shut-off doesn’t shut-off and fuel overflows.
I suppose buoyancy might apply less force than the weight, but the fact that its OK upside down suggests the valve is OK.
Floats full of petrol so sinking? Seems pretty unlikely.
This is a bit of info from another forum that may give you a little insight into the problem.
Do you know what causes gasoline to drip out of the over flow tube of your carburetor?
The short answer is that a tiny piece of dirt is most likely stuck in the needle and seat of the float valve, preventing the valve from fully seating. Or else your float valve may need to re re-adjusted, or replaced (due to wear on the needle valve and seat), to lower your fuel level in the carburetor float bowl.
However, I’d like to give you a bit more background on this important question. I used to think that the float valve in the carburetor operated like the float valve in the tank of a toilet: i.e., when water in the tank got low (as in after flushing), the valve would open until the tank filled and then close again. However, it is important to realize that (unlike our toilet tanks) the needle in the carburetor float valve is always closed. What varies is the pressure that the carburetor float exerts on the needle: relatively high as the fuel level increases, and relatively low as the fuel level decreases.
This means that the fuel pressure (on the inlet side of the valve) is in constant equilibrium with the pressure exerted by the needle (on the carburetor side of the valve), so that a very constant level is maintained in the float chamber.
Understanding that the needle of the float valve is always being pressed against the seat is important in understanding why any tiny bit of dirt can cause so much trouble. Once a piece of dirt gets caught between the needle and the seat, it will be held there and interfere with the needle valve’s ability to control the fuel level, until such time as fuel is drained from the carburetor and the piece of dirt is flushed away. This is the reason for the flushing procedure of the fuel system, by removing the drain plug from the bottom of the float bowl and let enough fuel run out, which will usually rinse off the the debris that is on the needle valve and seat, as fuel is running out of the float bowl drain plug hole.
To help prevent this problem from happening, again. It’s a good idea to put a good inline fuel filter between your gas tank and carburetors that keeps your fuel system very clean going to your carburetor’s float valve and seat, which also prevents having other problems in your carburetor, too.
In addition to dirt causing the valves to stick open, I have seen a few cases where the brass seat of the float valve needs to be polished (smoothed out) by pressing and rotating a short pointed hardwood dowel into its small orifice. Dowels of 3/16†diameter work well. I have even had to clean up brand new seats in this fashion before they would stop leaking.
As far as I can tell, the fact that no fuel passes the valve when the carb is upside down with the float bowl off eliminates any problem with the valve seat.
The pressure in that configuration, (created by the weight of the float assembly) may be greater than in the operating condition, when the pressure is created by the buoyancy of the floats, but that should not have changed.
I tried swapping in some floats from a scrap Kymco Zing (stolen and partly recovered. long story). This carb isnt the same, having a different accelerator pump arrangement and a wider throttle slider, but some components (for example, the jets) seem to be interchangeable.
It also overflowed from the drainpipe, ( the end of which was higher than the top of the carb) when fitted with these floats (with the original valve).
Only obvious thing to try is bending the wee tang thing so the floats sit deeper and possibly exert more pressure on the fuel cutoff valve, which I’ve always avoided doing up to now.
Just bending something to get it correct seams counter to engineering practices but it works, just do a little at a time to see it works and still filling with the correct amount of fuel to keep the motor running.
That sorted, no longer flooding, back to fiddling with the floats.
SYM manual (Chinglish and different model, but maybe better than nothing) has
"Checking fuel level
…To get the correct reading, position the float meter in the way that float chamber face is vertical to the main jet."
This makes no sense, (since that relationship is cast in alloy) but the picture suggests they mean distance from float chamber face to top of the float should be 14.8 mm.
Unfortunately, carb appears to be on its side (rather than upside down which would standardise the effect of gravity) so I guess its back to trial by petrol and a lot more error.
Keep either not delivering any fuel at all, or flooding, and sometimes seem to Defy The Laws of Physics to do it, for example, leaking from the body/float bowl join when the level in the clear drain tube serving as a sight glass is 3 cms below it!!??
These carburettors should actually give less trouble than the car carbs I’ve had dealings with, since they are relatively simple, but its not working out that way so far.
At the risk of repeating a Clarkson Cliche, cars are just better (well, old ones anyway). They don’t keep falling over, for one thing.
Looks to be close to kick start and clutch pack, (R side) and a relatively long way from gear change and timing chain bits. (L side) so the latter would have to be very broken to be the cause.
OTOH they might be very broken. I assume something is.
Wondering if dipstick could have caught in the kickstart return spring coils, perhaps if the spring was broken.
Oil strainer, accessed on this machine through a case-port, so you dont have to split the case, has quite a lot of metal bits in it, plus something that looks worryingly like a wee Woodruff key.
Oo-er
Trouble splitting the case. Years ago I was bodging a dodgy rocker cover gasket and some Taiwanese rude mechanicals came up to look at what the weird foreigner was doing.
One of them came back with some Nan Pao contact adhesive, which I declined, with thanks.
If that’s part of Taiwan culture, difficulty taking things apart might be expected.
I’ll try spraying carb cleaner inside, and maybe some heat.
If they have used gasket sealer sometimes you can work your way around with some strong braided fishing line.
That is quite worrisome, hopefully the metal bits are from the woodruff its self and not the crank and gears.
I take it the bike is in no condition to but it in gear and move it back and forth to see if there is any play in any or all of them?
Under magnification doesn’t look quite so Woodruffian, and I’m not sure how much of the debris is metallic. Didn’t have a magnet handy, but that should be informative.
Re looking at changing gear, should be doable if I can get it apart.
Taiwanese contact adhesive seems to be not to blame, just lousy Japanese (universal?) design.
No clue as to the cause of the dipstick damage. Lots of varnish but nothing loose rattling around, and the return spring for the kickstart isn’t accessible. End of the stick is very close to the casing, but its rather positively located by design (compared to your typical car) so dont THINK that should have been an issue.
Impressed by how little oil these things run with.
Need to find a suitable bit of gear jamming plastic before I can hopefully open up the centrifugal oil filter.
