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Over-reactive Throttle / Sputters / White Smoke(SOLVED)

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Re: Over-reactive Throttle / Sputters / White Smoke

PostAuthor: waitwhatsamotorcycle » Thu Mar 01, 2018 5:13 pm

Thanks Flyingdog, I called it a night after I saw that I would cut something open in order to fix/test it. Good to know there’s posts out there that show fixing the wire when it’s molded in the coil. In my case, nothing detaches from anything. If I’m going to try anything I’m going to have to do some surgery.

Questions:
-If my primary coil resistance is good, then does that mean for sure that my coil is good, and that it’s just a problem with the spark wire?
-When/If I figure out how the best way to take the cap off, what would be a “bad” resistance range for it?
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Re: Over-reactive Throttle / Sputters / White Smoke

PostAuthor: mark75 » Thu Mar 01, 2018 7:58 pm

might look at this as you consider coil/cable relationship ---> viewtopic.php?f=5&t=7049
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Misfiring Cyclinder

PostAuthor: waitwhatsamotorcycle » Thu Mar 01, 2018 10:42 pm

I took the cap off (apparently it just screws right out!) and tested the secondary coil without it and it measured at 12.68k ohms. It makes sense since the reading with the cap was 17.1k ohms, and there's a 5k resistor in the cap. The weird thing is that the cap wasn't giving a readout at all! All the components inside the cap were conductive, the part of the cap that screws into the wire was conductive, but the inside of the cap where the resistor and spring go wasn't. How the heck do you explain that?! It's driving me crazy!!! How does some material that was conductive all of a sudden stop being conductive :tf: (If you think it's something I'm doing wrong in measuring here's how I got to that conclusion. I got two paperclips (wire) to extend my probes, check the resistance of those two extended probes - 0.2 ohms. Then, I stuck those two things all the way down into the cap where the resistor is supposed to go, make sure they don't touch, and get absolutely nothing, no matter what range I put in the multimeter. They're only a 1-2 millimeters apart touching the bottom of the clean cap, and it might as well be wood! I put everything back to how it was. Components of the cap back in, the cap back onto the wire... the exact way I got a readout of 17.11k last night, and NOTHING! What?!) :hair:




Anyway! the resistance of the secondary coil is too high with the cap on, but without the cap it's in the right range.Would it be possible to get a new cap with a really low level resistor or none at all in it, since the resistance is already high enough? Or do I have to get a new TCI, and a new cap with 5k resistance to total 13k? Nevermind, I just saw Mark's latest link. I'm going to get a new cap without a resistor. But can someone please try to explain why one side of my old cap just turned to wood over night?
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Re: Over-reactive Throttle / Sputters / White Smoke

PostAuthor: waitwhatsamotorcycle » Fri Mar 02, 2018 12:42 am

Alright! I'm going to heckin lose my heckin mind. :skull:

I guess I just broke my other one! I took my other cap off. Tested it for resistance. ~5k. Cool. Took it apart, try testing it without the resistor or screw... Nada. Put it back together EXACTLY how it was before. Made sure to clean all the components off, put them in with tweezers. Test it. NOTHING. Holy shift. HOW?!
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Re: Over-reactive Throttle / Sputters / White Smoke

PostAuthor: XV535 » Fri Mar 02, 2018 8:54 am

choppin wrote:I have always been told that through the carbs is lean and pipes rich. To me it sounds like it still has an air or vacuum leak.


BIKE TICKS OVER OK BUT ENGINE RACES WHEN THROTTLE OPENED.

This cannot be an air leak on the manifolds or the engine would not tick over at low revs.

If the bike runs at 1000 rpm before the throttle is touched it cannot be an air leak on the manifolds. The reason is that if there were an air leak, it would pull fuel through and override any tickover, racing the engine even before the throttle is touched.

In a case where the engine races after the throttle is opened, it is likely that the throttle has been flipped open wide and then shut back to the desired position, which under normal circumstances would be OK as the slide will move back under the spring pressure, but if a slide sticks it would stay open at a wider position than the twistgrip position would suggest it should.

The way to test this is to turn it on, let it settle at tickover, and then open the throttle very slowly and gently to see whether revs are progressive, taking it up to high revs, then slowly adjusting back.
If it is a sticking slide it will be very easy to tell from this.

One problem I have found with Mikuni carbs is the slide sticking in the bore if it is inserted in a different rotational position than it was originally.
In theory if you take a slide out, it will go back without a rotational displacement as the notch in the housing will line up with a small lug on the rubber diaphragm BUT if the carbs have been dismantled, the diaphragm may have been rotated, so that its slide goes back into the carb bore in a different rotational orientation.
To check for this, take the side cover off and put it and the spring aside somewhere clean.
Gently move the slide back and forth in the bore to see if there is any slight binding, sensing the fit just as you would if using a feeler gauge. if there is any binding at all, continue sliding back and forth whilst rotating the slide until a point is found where there is no resistance. Mark that point for reference and repeat the test until you are sure that the very best orientation has beeen found before turning the diaphragm on the slide until its lug locates in the carb body in the position where the slide has its best fit with the bore. Re check before refitting the spring and cover.
Repeat for the other carb or carbs.

Avoid mixing carb slides and carb bodies, and IF a good sliding fit cannot be found make sure that the slides have not been accidentally swapped between carbs.

If you do start deliberately swapping to find a best fit between two carbs and slides mark which carb had which slide originally before swapping so that you know that you can go back to where you started. Mating parts do wear in together, and are often OK until disturbed.

Do carefully clean the carb bore and slides BUT DON'T clean them with anything abrasive or either they WILL stick and the throttle won't shut down when it should, or you may cause the slide to be too slack in the bore which will mean very poor throttle control and poor fuel economy.

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Re: Over-reactive Throttle / Sputters / White Smoke

PostAuthor: waitwhatsamotorcycle » Tue Mar 06, 2018 4:38 am

Thank you xv535 for the extensive post. There was an issue that was caused from kinked calm air hoses, so you were right.

It's about time this post should be retired. It turns out that I have been dealing with at least three different issues back to back (just my luck) which I confused for one issue. And some things weren't actually issues.
-The over-reactive throttle was just me getting used to the "new" dual carbs.
-Sputtering and backfiring was caused by kinked calm air hose
-Stuck high RPMs was actually and a misfiring cylinder that started firing again after I unknowingly reset the idle speed to compensate for the dead cylinder
-White smoke was just from some oil that was burning up that got in the cylinder when I was changing my carbs. It burned off relatively quickly
-I'm currently working on why the front cylinder isn't firing, but I made another post in the electrical forum.

Thank you all for sticking through the confusion.
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