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Post by cyborg on Oct 17, 2015 14:25:29 GMT -6
humor me,,,take the two leads off the sensor,,,turn the bike on,,,and put the two wires together from the sensor to see if the fan lites up,,,if it does not check the ground for the fan,,,if everything is testing good to go there's something so simple its looking you in the face,,,when you do find it it's going to be so obvious you're going to want to hit yourself in the head with a hammer,,,but don't kill yourself ok? we need all the members we can get,,,lol
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Post by bobf on Oct 17, 2015 17:39:11 GMT -6
OK cyborg, not to humor you at all. Just willing to try to find the reason. Nobody has pointed it out yet, so I give you a try too.
I will try what you say. I don't expect the fan to run. But a missing ground could be the problem. Late tonight here, getting dark, so maybe tomorrow I will give it a try.
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Post by bobf on Oct 17, 2015 18:29:06 GMT -6
Well, I was wrong when I said the fan won't run. I worked under lights but really prefer daylight. Actually what you asked me to do was the same as what I had tried before. But instead of shorting both post first. I just got both sensor wires together and nothing happened, so I turned on the switch and the fan started to run. Same as before, nothing ran till the switch was turned on.
Now on the schematic it shows two wires going to the minus side of the battery and two wires to he positive side also. I have been wondering about that and looked for the second wire for the negative side in the past. Tomorrow that will be a search for me. If that is the problem, then your idea is a winner. I will start to looking in daylight tomorrow. The schematic shows a wire to the negative post and to a ground point. Is reality also like a schematic? I will take a look tomorrow.
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Post by ellpee on Oct 18, 2015 9:22:20 GMT -6
Ellpee still alive and kicking. Ribs and back somewhat painful but improving. Lotsa road rash scabs, just in time for Halloween. Sure glad I wore my helmet, or the story might be quite different. Still no memory whatsoever of the circumstances of the crash.
So with key on, 12v flows to the sensor. When the sensor gets hot enough, 12v passes through the sensor and flows to the fan, which runs, telling us the sensor is good, connections are good, fan motor is good, and fan has a good ground. When the sensor is NOT hot, shorting 12v from that blue wire directly to the fan, bypassing the sensor, also activates the fan. So that's the whole taco, nothing wrong with anything related to the fan circuit. If you're saying all that is true and the fan still won't run, you have officially stumped me.
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Post by bobf on Oct 18, 2015 9:57:22 GMT -6
That is why I ordered a new temp sensor. So far the sensor has not turned on the fan. The only way it does is if I short the leads or do as I was asked and twist the wires together. I have found the original temp sensor that I tested in the pot on the stove. So I may just put that back into the radiator next go around.
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Post by bobf on Oct 18, 2015 10:09:10 GMT -6
cyborg, I just went over the wiring and can't find any loose connections. My memory does tell me that at one time I had more than one connection on the negative post of he battery. Maybe just thinking of the outside charger system I have used in the past.
I also checked against the schematic and found the cable attached to the negative post of the battery goes straight down about 6 inches below the battery to a frame ground position. Then a green wire goes from that point into the cable harness. From this ground point their is a heavy black wire that goes down to the starter motor.
So for now I have no idea what you mean about missing ground. All things seem to work but the fan. If you do have some solid idea please post it as I have tried to follow your suggestions and got nowhere at all. I do need some inspiration from someone.
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Post by ellpee on Oct 18, 2015 16:16:59 GMT -6
Makes sense. That 6" cable would be the main battery-to-frame ground. Grounding anything anywhere else on the frame makes it part of that circuit, feeding back to the negative side of the battery.
On my schematic at least, the ground wire for just about everything else is green, so they probably all tie in somewhere to the green you found attached to that same frame ground position. And the heavy black one is presumably the starter ground.
All of which tells you nothing much about why your fan won't run, but for the price of a new sensor you'll know soon if that's the gremlin. Since it passed the pot of water test it seems unlikely, but it's supposed to start letting juice through at around 167 degrees as I recall, so if it's not doing its thing until a considerably higher temperature, I suppose that could explain it.
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Post by bobf on Oct 18, 2015 19:48:24 GMT -6
ellpee, the sensor I tested is still on the work bench, never yet put back in the radiator. Briefly I could not find it so I ordered another new sensor. I guess if the new one does not show soon, I will put my tested one in the radiator. What I did not have is a temp reading as it opened. Maybe that should be easy to find.
But it may not be the problem at all. I also put in a new carb. It too had some wires to connect. So maybe I should get the old one out and cross check the wires to see if I did OK.
This is a sticky old mystery. I will win, if I don't just give up.
Also, with this new carb I would like to see where all the hoses should go. It does not idle as well as before.
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Post by cruiser on Oct 20, 2015 13:28:39 GMT -6
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Post by bobf on Oct 22, 2015 14:47:37 GMT -6
Today., and yesterday, I have been trying to reset the valves. Just not doing well at all. Some just maybe that I have the idle speed too high. But after lots of time running, the fan came on finally. Just not sure what I may have done with all my connecting and moving of wires while chasing the schematic. Many connections were taken apart and reconnected. Oh well, glad to hear that the temp sensor is good and the fan does run.
Back to timing. Can't tell which is exhaust or firing. But the front one does not change much at all and the rear one will change from running at 3,000 to 4,000 down to near nothing or stopped. Resetting the idle screw does not fix this.
I have been trying to use the one illustrated where with hot engine running, you loosen the nut, drag the arm to where the clicking is just starting, then tighten the nut. Just not working well for me at all. On the front one I can slip it along and try to tighten but not much changes on the engine speed and the arm seems to move. On the rear one it seems that full right on the arm means it slows or dies and if I move it to the front, the idle just takes off and rpm's go wild.
Tighten the nut and the arm does move, even with me trying to hold it with my pliers
I have been watching some films and one seemed like I would like to try it. Do it on a cold engine. Set timing to top dead center, then take each valve adjuster loose, bring the adjuster arm up till you feel the valve. Then back off a bit and lock the arm there. Then I would mark the arm position relative to the notch in the adjuster pivot area. This would give me a visible starting point for the active setting. The setting should not be far from this mark. And if close to where it says, I hope this would allow me to set a decent idle speed, which should make the adjustments much easier.
How do we find TDC on the vertical 250cc engine? I am mostly torn down now so it should not be much of a job to do.
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Post by bandito2 on Oct 23, 2015 10:02:48 GMT -6
I found Youtube video that might of help for you. I think the Helix clone engine is basically the same. The only reliable way to set your valves is on a cold engine that is not running while you set them. Once the valves are set, if the bike is still not running right then at least you will know it is not because of improperly set valves.
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Post by bobf on Oct 23, 2015 10:40:26 GMT -6
Thanks Bandito2. That is the film that I was talking about that got me to wanting to do a more direct way of setting the valves. I have no peek hole to look into. By this film, I guess I will have to take off the stuff on the left side in order to set the TDC. That is my question about my Roketa MC 54 250B engine, the vertical 244cc engine. Most of what I have been able to find on the forums is people talking about their horizontal 250cc engines. Which should have been shown as MC 54B 250 but for some reason they kept posting MC 54 250B. Anyway, my question remains.
I think I must remove the belt cover and spark plug but where are the timing marks on my scoot. I will go out now and remove the belt cover. Maybe then I will see what to use.
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Post by bobf on Oct 23, 2015 11:26:49 GMT -6
OK, I now have the belt cover off. Have looked for timing marks but find none. Seems strange there are none. So I ask again, where are the timing marks.
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Post by bobf on Oct 23, 2015 12:35:08 GMT -6
OK, I have come across some inputs about valve adjustments. One talks about a port on the right side of the engine, so I looked at mine. It appears I also have that port. Will give it a try tomorrow. The wife goes to the doctors today so I must stay ready and clean.
Seems like all these engines have their own structures and personalities. I do want this mechanical way of first setup and then knowing where the valves matched the specs and marked on the parts, I will have a good start and know approximately where we should be in future set ups.
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Post by bobf on Oct 24, 2015 10:32:52 GMT -6
OK, I give up, I surrender, I can not find a way to determine TDC for my scoot. The only thing that seems to be available is a screw driver in the spark plug hole. No timing marks could be found. I have no peep hole on the top. Nor do I have a peek hole on the right side. What I thought would be a peep hole turns out to just be a machined surface for bolt head clearance. Thanks for the inputs that I did get, just nothing I could find on the machine.
Going back to the top side and listen for clicks. I did read enough comments about that but still not sure what I have on my hands so it will just be a blind effort for me. I should never have attempted to reset the valves as the engine was running pretty well at the time. Till I fixed it, now not so good. So I will start with the screwdriver in the spark plug hole and proceed. Hopefully to victory.
Evening: Well I did put the plug back in, had to charge the battery a bit, cranked enough to start. Ran a few seconds then shut off. The battery is still on charger. Tomorrow I will try to do the topside adjustment.
Interesting when it was cold, I could not move those adjustment arms. So tight I had to use the screw driver leverage to move them. Not free like some films have shown them. Tomorrow when it is warmed up, hot, I will see if that makes them looser and movable.
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