PirateLabs
Scoot Enthusiast
Posts: 296
Location: Bowling Green, KY
|
Post by PirateLabs on Jul 29, 2018 12:49:58 GMT -5
The saga continues.... Here is what I have done since my last post. Today, I installed a new carb. and I used the same jets that I was running in the other carb. 32 pilot and 85 main. Ran various sized wire through both jets to make sure they were clean. I use seafoam and the inside of the carb looks great after 2 years. I installed a brand new intake manifold and, I blocked off the single vacuum nipple because I disconnected the PAIR system and have a manual petcock so no need for any vacuum lines at all now. Just a refresher, a few weekends ago I installed the new cdi and new spark plug boot and wire and tested the output of the stator at about 60 volts ac around 4,000 rpm. At that time, I also replaced all of the fuel lines and installed a new filter. So, I have eliminated the enricher, (new one on the new carb.) and the slide diaphragm (again carb. is 100% new) intake vacuum leaks, vacuum line vacuum leaks, and some other stuff which I forget right now as I am still hot from working on this in the heat out there. Test drive today showed that...once again it will NOT even try to start on the electric starter at all. Not even a spit or pop. 3 kicks started it up after sitting for 2 weeks. I let it warm up and adjusted the carb but, it turns out that the same settings I was using on the older carb. gave me the best rpm on this carb. (3.5 turns out which is my summer setting) Set idle to 2,000 and let it idle for 10 minutes while I put my tools away. Jumped on the scoot and it ran very smooth and strong up to 38 indicated at 7,200 rpm (maybe a tad higher as the TTO lags just a bit) and it shut off again!!!!! (I have my cvt tuned to run about 8,100 rpm W.O.T. top end at 43 mph gps verified) I backed off the throttle and it idled down for a few seconds and then, it took the gas and I was off again...got up to about the same rpm and same thing happened so this time I just held the throttle wide open (I was getting pissed off) and kept leaning on it just to see what would happen and...the engine died. I coasted down to about 10 mph and pulled the brake lever in just enough to fool the starter lock-out switch and....broom.....it fired right back up. Got back home and shut it off. Just for the hell of it I tried starting it on the electric and...it would not start. This time...one kick and it fired right up and idled nicely. So, I am totally lost and frustrated that I am unable to diagnose what this is and fix it. I have never taken my cars, trucks or motorcycles to anyone for repairs, I have always done them myself since 1974 and, before that, I was tuning up my Dad's cars and doing the maintenance on them. Any and all ideas and suggestions would be greatly appreciated. I have another manual petcock on order just to eliminate that it has a restriction in it for some reason...causing me to drain the carb. bowl. That is what this feels and acts like but...the bowl should be plenty full enough to start on the electric starter like it used to do up until 4 weeks ago. Other than that, I am out of ideas. Thanks, Bill EDIT: I also wanted to mention that I have had no backfiring since that ride home the first time this began to cut out on me. Maybe my replacing the CDI helped with that...I do not know.
|
|
|
Post by FrankenMech on Jul 29, 2018 22:43:46 GMT -5
Is your fuel tank vented? Run a ground wire from the neg battery post to your frame. Run a ground wire from your engine to the frame. Run a ground wire from your CDI to the engine.
3.5 turns out on the mix screw is strange, it should be 1.5-2 turns.
|
|
PirateLabs
Scoot Enthusiast
Posts: 296
Location: Bowling Green, KY
|
Post by PirateLabs on Jul 29, 2018 23:20:35 GMT -5
Yes, fuel tank is vented and drains out of the tank very fast. Which wire is the ground on the CDI do you know? I know there are 5 wires in that plug but I will have to find a wiring diagram to locate the grounded one. 3.5 turns out is my hot summer setting which I have used for 3 summers now. (I didn't know what it was but tune it to the weather conditions, and when I put in the new carb. I counted how many it was so I had a good place to start when tuning the new carb.) I could go up a larger jet size and then run it less turns out but, my plug looks perfect with the 85 main and this setting. As I mentioned, the only other possible fuel restriction could be my manual petcock and, if I had some tubing the right size, I could make a test run without it but, I don't so, I ordered another one and it will be here in a few days and I will swap it out. I am just amazed that after all of the changes I have made that it does exactly the same thing at almost the exact same rpm and throttle setting. I will make another test run with the gas cap off just to eliminate that possibility.
One weird thing I noticed when installing the intake was that under the old, stock intake there was a 1/2" thick spacer and, the stock intake did not have that O-ring gasket at all, it had a full flange gasket on the top and bottom of that spacer. I am going to reassemble it next weekend with some RTV gasket stuff just to be sure of a good seal in that area.
Thanks,
Bill
|
|
|
Post by FrankenMech on Jul 30, 2018 13:41:29 GMT -5
There are actually several ignition system grounds.
The CDI ground, usually a black or green wire. The 120V ac coil ground. The timing pulse coil ground. The spark plug coil ground.
If any of those a being swamped out by the current from the electric starter your engine may not produce a spark when cranking.
|
|
PirateLabs
Scoot Enthusiast
Posts: 296
Location: Bowling Green, KY
|
Post by PirateLabs on Jul 30, 2018 18:53:31 GMT -5
There are actually several ignition system grounds. The CDI ground, usually a black or green wire. The 120V ac coil ground. The timing pulse coil ground. The spark plug coil ground. If any of those a being swamped out by the current from the electric starter your engine may not produce a spark when cranking. Thank you very much, I had not considered that as a possible cause. I also may be mistaken in "assuming" that these two symptoms (only starting with the kicker and cutting out at 7300 rpm) are connected. They may indeed be two separate problems. Bill
|
|
|
Post by FrankenMech on Jul 31, 2018 0:09:52 GMT -5
The starter motor uses a lot of current that is passed through the engine case. That current will take the path of least resistance back to the negative battery terminal. A bad connection in that circuit will raise the voltage on the engine case which will impact the voltage on all of those other ignition systems. Kick starting does not pass much current through the case.
I use two ground straps made of braided silicone insulated high flex wire from case bolts to the frame. My frame bolts have a heavy 10AWG ground wire connecting them back to the battery ground terminal. The 11-12AWG high flex wire can be purchased from Hobby Shops. It is used for making up RC car battery packs. I also position the ground straps so that there is no flexing at or near the connections.
Scoot wiring is often made of brittle undersize copper. Thin wires are used to save weight on scoots and motorcycles. Impure dirty copper is brittle. Impure dirty copper is cheaper than pure copper so guess which one is used by Asian wire harness makers... Remember, the stranded wire you buy in auto parts stores was made in China with absolutely no standards or quality control either for the copper or insulation.
There usually is a continuous ground wire in scoot wiring harnesses but it is real small (and brittle). It may even have a ground terminal for a connection spot mid-frame. That mid frame ground was not even connected to anything on my scoot. The frame is an adequate ground for a scoot or most vehicles. I just learned to supplement that ground on vehicles over 50 years ago to avoid 'chasing grounds'...
I make ground studs from a 6-8mm bolt in a threaded hole through the frame with silicone dielectric grease in the threads. I will jam-nut the bolt with star lock-washers and use another nut to fasten all the wire connections onto the stud. I also pay attention to the battery to frame ground point and wiring.
|
|
PirateLabs
Scoot Enthusiast
Posts: 296
Location: Bowling Green, KY
|
Post by PirateLabs on Aug 5, 2018 12:32:45 GMT -5
Thanks FrankenMech, that might be why it is not starting on the electric and I will run new ground wire as soon as I can.
Today, I installed the new manual petcock and took a test run. Once again, no start on electric but started on 1 kick. I am concentrating on my high rpm issue today though and, it took off great and pulled well up to about 40 mph and stayed there for maybe 12 seconds then just died in a long and slow bog which stopped as soon as I backed off the throttle. Once it recovered I hit it again and, the same thing...bogged until I backed off for a few seconds. Since this is still acting like a fuel starvation issue to me I took off my gas cap and made a few more full throttle runs. No change at all.
Once again, the fuel flow from the tank was pretty impressive when I removed the old petcock...it ran a full stream the full diameter of the gas line until I could get it connected to the new petcock, so, again I conclude that the screen in the tank is not blocked at all and the flow through my new fuel lines and filter is just fine. It still acts like a fuel situation to me but I have no idea how it could be now that everything has been replaced from the tank down to the intake port. A vacuum leak could stop fuel flow in the carb. but I am no longer running any vacuum lines at all with the single port in the intake blocked off with a vacuum cap and my intake and gaskets are new so...where else could there be a vacuum leak? Leaking valves maybe? Compression is very good judging by the way it pulls from 0-40. It pulls as good as it ever has since I have owned it.
I do not think it is electrical as it is more of a bog than if I just hit the kill switch...in other words, the engine is still trying to run when it is dying but it is not getting enough of something it needs to maintain that rpm at W.O.T.
This is very frustrating.
Bill
|
|
|
Post by FrankenMech on Aug 5, 2018 17:32:46 GMT -5
You can bog out from a rich condition as well as a lean condition at WOT.
|
|
PirateLabs
Scoot Enthusiast
Posts: 296
Location: Bowling Green, KY
|
Post by PirateLabs on Aug 5, 2018 18:57:48 GMT -5
You can bog out from a rich condition as well as a lean condition at WOT. Sure, I agree. But, in this case, I am W.O.T. from 0 all the way to a little over 40 mph which takes about maybe 15 seconds or more before this condition begins. I once had water in my gas and every time I opened the throttle anything past 1/2 way it bogged big time, no matter what my speed or rpm. I had no idea it was water until I checked. Fuel condition was one of the first things I looked at because of that experience. This runs great from 0 to around 40 mph and, if I back off before I get up there...it continues to run fine. When it bogs and I back off for maybe 5 seconds, I can go wide open again for maybe 5 seconds and it happens again. This is why I thought it was fuel delivery related but, now I can not see how that is possible. I have not tried it but I believe it would run all day at partial throttle like it did when this first happened, and I was able to drive the 5 miles remaining back home from work. I am stumped. 100% stumped. I really should have made a video when I first posted about this..maybe I can next weekend. Bill
|
|
Moat
Scoot Member
Posts: 88
|
Post by Moat on Aug 5, 2018 21:16:01 GMT -5
I've no idea what airbox/filter/snorkel you're running, but a collapsing intake runner/snorkel or even air filter comes to mind.
I'd also probably try rolling to a dead stop during the WOT bog, then immediately gander at the plug for any clues (i.e. - wet/dry, black/clean, etc.).
A fuel restriction inside the carb inlet barb or behind the float needle seat could be a possibility, too (unless you've already replaced/been there).
Otherwise, lost here, too...??
Bob
|
|
PirateLabs
Scoot Enthusiast
Posts: 296
Location: Bowling Green, KY
|
Post by PirateLabs on Aug 5, 2018 21:31:51 GMT -5
I've no idea what airbox/filter/snorkel you're running, but a collapsing intake runner/snorkel or even air filter comes to mind. I'd also probably try rolling to a dead stop during the WOT bog, then immediately gander at the plug for any clues (i.e. - wet/dry, black/clean, etc.). A fuel restriction inside the carb inlet barb or behind the float needle seat could be a possibility, too (unless you've already replaced/been there). Otherwise, lost here, too...?? Bob Interesting thought. I am running a cone filter. Those are made pretty cheaply as over the past 2 years, I have gone through 4 of them including a uni because the rubber that mounts it to the carb. always rips and they fall off or almost fall off. It is possible that the inside of this filter has collapsed a bit which would restrict the air only under the most severe conditions, like W.O.T. for a bit at maximum rpm. I back off, and it gets the air it needs and goes on until I do it again. I like it. This idea is a lot more than I have so next, I will make a quick run with the air filter off. Thank you for suggesting this. (Oh, the carb. is brand new and the same condition happens the same way as with my other car.b before I replaced it in my attempt to trouble shoot this.) Bill
|
|
Moat
Scoot Member
Posts: 88
|
Post by Moat on Aug 6, 2018 5:31:58 GMT -5
DoH! Yeah, now I see above that you've already replaced the carb - sorry... Another (yes - rather obscure, remote chance) thought is; cracked cylinder head or loosening valve seat - happening after a period of sustained WOT allows the head to heat up/expand enough to open the crack or drop the seat, reducing compression temporarily 'til it loses power and cools down enough to close/tighten back up and seal. Kinda' extreme idea, but certainly a possibility (as seems about anything with these cheap Chinese scoots!) - one I almost hate to mention, in case you were to tear into it and find nothing wrong... and end up pi$$ed... Bob
|
|
|
Post by GrumpyUnk on Aug 6, 2018 10:20:56 GMT -5
Have you checked the ROUTING of the fuel line? I know when I fool with this stuff, I do it with the 'bucket' removed for access. Is it possible when you put it back it can pinch the fuel line? The description absolutely fits running out of gas as afar as I can tell, especially when backing off and then going again seems to help. tom
|
|
PirateLabs
Scoot Enthusiast
Posts: 296
Location: Bowling Green, KY
|
Post by PirateLabs on Aug 6, 2018 13:17:46 GMT -5
Have you checked the ROUTING of the fuel line? I know when I fool with this stuff, I do it with the 'bucket' removed for access. Is it possible when you put it back it can pinch the fuel line? The description absolutely fits running out of gas as afar as I can tell, especially when backing off and then going again seems to help. tom Well Tom, I spent a lot of time getting the routing "just right" so as to not have any sharp bends or uphill areas or any abrasion issues but I have to say I had not considered this. I also do just about everything with the bucket removed. I will check this although this first happened with the old fuel line route which I had been running for over 2 years and, the bucket had not been removed for several weeks prior to my first "event". I guess it is possible that my old fuel filter was clogged and when repairing that by replacing the entire fuel line and adding a new filter, I created a pinch which did the same thing as a clogged filter...not likely...but possible so, I will check this when I get home. Thanks for this suggestion. My new silicone fuel line is soft and I can easily cut off the flow with two fingers so even if it is not pinched now...it is certainly something to look out for in the future. Thanks, Bill
|
|
|
Post by gsx600racer on Aug 25, 2018 19:31:25 GMT -5
|
|