Another Ignitor box problem (updated with correct thread)

phatdawg · Full Member Joined: Nov 19, 2007 Posts: 60

I just did the transitor test see thread www.650rider.com/index...ic&p=25104

The test you put the leads one way and the result should be infinate, then switch the leads and the reading should be zero or not infinite. My reading is 522 on both of the non infinate readings. Is this ok or should the transitor be replaced?

I already replaced this box once. The replacment worked for a while and then started the trend again this morning (had to push the bike hom today). The bike will start up for a few minutes and then just die.

Thanks.

phatdawg · Full Member Joined: Nov 19, 2007 Posts: 60

Even a quick post would help. Perhaps I should just change the transistor? Going back to points is looking real attractive right now.

Skip · Posted: July 18, 2009, 10:23 am Post subject: Re: Another Ignitor box problem

Ive been there,done that phatdawge.
Take my advice and no matter what numbers you come up with for testing the transistor,replace it.
It's cheap and takes a little time.You must be very careful not to apply more heat than nessessary to remove/replace the transistor.
Also use this transistor( MJE5742)as it mirrors the specs of the OEM one.
You can buy this at any electrical store but it may have to be ordered.

phatdawg · Full Member Joined: Nov 19, 2007 Posts: 60

I just replaced the transistor. Almost time to go see if it workded.

gordo

Phat, are you using a heat sink to solder that transistor in place? If not, that's the problem. Too much heat getting absorbed by the transistor. I use a small set of hemostat's on the leg that I'm soldering. They take the heat, so it doesn't go into the trans. I remember reading about you when you posted that problem & fix a little while ago, so, that's why I'm asking. Good transistor's should last along time. And Rat Shack aren't alway's the best quality. Might try a radio repair shop,as those guy's use better stuff, so it doesn't come back in a week. If you are using the heat sink, I'll just shut the hell up, & you can call me Elmer. Only you, though.Hee Hee.

phatdawg · Full Member Joined: Nov 19, 2007 Posts: 60

I got the last message (that I should heat sink the transistor) after I had already done it. The result is the same; won't fire kicking or starter. So a new transitor did not do it.

Looking at this thread: xs650temp.proboards.co...read=10600

I was wondering if maybe my coil went out (it is a new HP Mikes XS coil). The primary showed 2.8 ohms (on the 200 scale). I measured ohms on the secondary coils between the plug wires I measured where they attach to the plugs and it is infinite. I can't tell if this is right or not. Maybe I will do one of the jumper tests.

phatdawg · Full Member Joined: Nov 19, 2007 Posts: 60

More improtant info. The bike will not even fire up now. No spark.

pamcopete

phatdawg,

Use your highest Ohms scale when measuring the secondary (plug wires). You are looking for 23K Ohms if you have the 5K caps.

phatdawg · Full Member Joined: Nov 19, 2007 Posts: 60

I think that it is the coil. I used the 20K scale on the ohm meter and put leads on the end of the spark plug wires where the plugs attach. It read infinite.

Interesting that this is a MikesXS coil with less than 300 miles on it. I guess if this is the trouble it happens once in a while on a newer product? Or could there be some other electrical component on the bike that caused this?

pamcopete

phatdawg,

Try the 200K scale. Also, measure right in the wire towers without the wires.

phatdawg · Full Member Joined: Nov 19, 2007 Posts: 60

pamcopete wrote:

phatdawg,

Try the 200K scale. Also, measure right in the wire towers without the wires.

I'll give it a look.

phatdawg · Full Member Joined: Nov 19, 2007 Posts: 60

pamcopete,

You probabily just saved me some $$. I took the wires off the coil and got 18.4 Ohms at the coil. I was not getting my probe far enough in the boot. Its easier to take the reading with the plugs hanging on there.

Now I'm back to suspecting the TCI.

phatdawg · Full Member Joined: Nov 19, 2007 Posts: 60

I have one other TCI. I think that I will put a new transistor in that one and try again. As of right now neither work.

If I just power to the pos side of the coil, does that just take the safety switches out of the loop?

pamcopete

phatdawg,

I guess you meant 18.4 K Ohms? What is the part number of the coil? If it is Mikes 17-6803, then it should be 13 K Ohms. Go to Radio Shack and buy some 15 K Ohm resistors. Measure them with your Ohm meter to verify its accuracy. Still cheaper than a new coil

The only real killer safety feature is the side stand switch and relay. You can remove the side stand relay under the left side air filter cover which will allow you to start the bike on the side stand, but you are better off (safer) with the bike on the center stand, gear in neutral. Check for power to the coil with the key and kill switch on.

I also reccomend this transistor instead of the TIP 120:

otorola MJE5742

This transistor is made for rignition systems. The TIP 120 is not.

phatdawg · Full Member Joined: Nov 19, 2007 Posts: 60

So there is not 12V to the coil (with both ignition switch on and kill switch on and during cranking). I think it was hovering around 9v during cranking.

With the plugs out of the head and connected to the wires, I cranked the engine with one grounded to the block and there was nothing.

I jumped a wire from the pos batt to the pos primary coil (red/white) and this touch gave me a bright spark of the plug (also the neutral light flashed).

Those Motorola MJE5742 transistors are backordered. Should I just try putting one of the "Shack" transistors in or try something else?

pamcopete

phatdawg,

If you are not getting battery to the coil, thats not the TCI. The battery comes from the kill switch and ignition switch.

phatdawg · Full Member Joined: Nov 19, 2007 Posts: 60

pamcopete wrote:

phatdawg,

If you are not getting battery to the coil, thats not the TCI. The battery comes from the kill switch and ignition switch.

I will look this up now but does this side of the circuit include the sidestand swithch? Gosh, I hope that its not the ignition switch. The kill switch is a MikesXS replacment.

Thanks Pamcopete. Hope it get going in the right direction now.

phatdawg · Full Member Joined: Nov 19, 2007 Posts: 60

Keeping this near the top. I have changed transisters on both of my TCI's now and still no spark. Looks like the only thing left to check is the pickups. Stay tuned.

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