Look for an MP08 Honda coil on Ebay.... they're cheap.
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Started the Special ll refurb
- Thread starter flyerdon
- Start date
Yes, the Honda MP08 coils are cheap and work well. Here's a write-up on installing one .....
http://www.xs650.com/threads/honda-mp08-coil.55408/
http://www.xs650.com/threads/honda-mp08-coil.55408/
flyerdon
XS650 Enthusiast
I found a used MP08 for sale on Ebay and ordered it. $17.35 with shipping. Although the wire are included, is there a specific wire and cap that needs to be used with these coils? I might want to put new wires and caps on after I get it and want to make sure I get compatible items. For that matter, are there any other dual coils out there that are good replacements for the Yamaha coil? I sure hope this helps me get my issue settled.
flyerdon
XS650 Enthusiast
One more question for the refurb saga. Today I decided to see what kind of spark plug caps were on the bike. I assumed they were stock (you know what they say about assuming) and I read 1.1 K ohm and thought it might be bad then I checked the other and got the same reading. Hum.. then I noticed they were actually labeled 1K ohm. I thought these things were supposed to be 5 K ohm? Then I got to wondering if the absence of resistance in the plug wire could have caused the steady decline in spark since I bought the bike? I'm really not sure if it's significant or not.
I think it's more about RFI but hey many "big" problems are just lots of little things that all add up to poor function.
Yes, 5K ohm caps are the norm. Not sure if 1K ohm caps would cause issues or not. You're going to need 5K ohm caps anyway for your new coil so you could get and try them now with the old one if you like. The cap of choice for most of us is the NGK LB05. I prefer the terminal stud type as I think it grips the plug better .....
Most bike shops have or can get these for you. I never tried an auto parts store but maybe they can too, and probably at a better price.
You'll want 7mm metal core non-resistor wires. I use silicone wires from kits for VW Beetles ....
Most bike shops have or can get these for you. I never tried an auto parts store but maybe they can too, and probably at a better price.
You'll want 7mm metal core non-resistor wires. I use silicone wires from kits for VW Beetles ....
flyerdon
XS650 Enthusiast
OK, thanks for the info
flyerdon
XS650 Enthusiast
I replaced the coil with a MP08 and now the secondary impedance is good but I'm also back to getting a single spark when I hit the starter button. If I keep hitting the button I'll get a single spark as soon as it starts to turn over but only one even when it keeps turning over. I wonder if there is a threshold voltage where it simply won't fire. I measured the 12v at the primary of the coil and only see about 11.5v so I'm losing a volt or so somewhere. I'm trying to trace that down but I'm also getting tired of replacing electrical stuff, and think a whole new system may be the way to go.
flyerdon
XS650 Enthusiast
Finally I've made real progress, in fact, I'm sitting on top of the world right now. I was getting pretty depressed after buying a coil on ebay that really didn't help my problem at all. Although I knew it was good because the secondary impedance readings were good, it still wouldn't give me consistent spark. I was very close to putting a "for sale" sign on the thing but I decided to keep at it a while longer seeing how I had about $750 bucks in the thing and knew I couldn't get that out of it if it wouldn't run. So...…….I broke open the TCI after reading a few threads about repairing them but it looked like new on the inside and all the readings I took for continuity and resistance were good. Then I decided to measure between the blades of the connector and the terminals inside. Those readings looked quite suspicious and the blades looked like they had oxidized quite a bit so I spent a half an hour cleaning up all six blades on the connector. Wow, what a difference that made. It was still running pretty rough but it would run, almost sounded like it was running on one slug but both pipes were hot so I knew both cylinders were firing, if not as regularly as they should. So I went back to cleaning the blades of the connector to really make them as clean as I could. Holy Moley, the thing started real easy and ran like a new bike. You could have knocked me over with a feather because I had all but given up. I took it around the subdivision a couple times and it didn't miss a beat, far better than I had imagined was possible. I had cleaned all the connectors in Evapo-rust but I think now that the process of eating all the rust must had had a reaction that left a high resistance coating on the connectors. For whatever reason, everything else worked just fine so I was a bit amazed that it seemed to only have a negative effect on the TCI connection. Anyway, be aware, oxidized connectors can cause some weird problems and from how bad my experience was (absolutely intermittent spark to no spark, back and forth a couple times), I figured it was something much different that suspicious connectors. All is good now though and it runs like it just came off the factory line. All lights are in working order, all instruments are working and the brakes are now functional (thanks to a new caliper and master cylinder in front). I couldn't be happier if I had won the lotto.
Attachments
Yes, that TCI connector is in a bad spot, right next to the battery. It's subjected to all sorts of battery acid and battery acid fumes so it can get quite corroded up. I actually had to replace a couple of the spade crimps in the plugs because they were corroded away so much.
flyerdon
XS650 Enthusiast
You have to wonder why in the world any engineer or even design specialist would put the heart and soul of an ignition system or really any electrical major component under and side by side with the battery box. Today, with our sealed and much better batteries it wouldn't be so bad but back then so many batteries were still lead/acid with overflow tubes. My bike showed definite signs that acid had been spilled right down the frame, battery box, chain guard, and everything else in it's way toward mother earth. Amazingly it didn't look like any had entered the TCI inside. That's amazing in itself. Also from what I can see, the bike has been over on it's right side, probably from a tip-over because I can see minor damage to the right engine case, footpeg, and brake lever. Nothing major but it's there if you look for it.
I've had to straighten many a rear brake pedal, lol. Luckily they're mild steel so can be bent back in shape pretty easily. I had to straighten one on a local guy's bike. The thing looked like a banana, lol, yet the guy rode it around like that. The foot pedal part was probably a good inch above the footpeg. This guy wasn't the sharpest tool in the shed by any means, lol.
In the engineers defense the battery box is the least vibrating part of the XS650. IF the overflow tube is kept in place,
the acid isn't a problem.
This is very encouraging given the problems with my XS. Bike refusing to rev, spark seems to drop out as engine speed goes up, suspecting the rotor magnets, the coil, etcetera. Good to hear that just a bit of work on electrical connectors - cleaning & re-making - can work wonders as on your bike. Cheers, Raymond
flyerdon
XS650 Enthusiast
In retrospect, I had wondered if the connectors were in good enough condition to make contact like new ones would have, but being in a bit of a hurry, I decided to get the harness back on the bike so I could complete putting it back together so I could get it running. It might have been worth the money to get a new harness and a few micro-brushes to clean all connectors on all the various plugs. I'm sure that would have saved me some time in the end. But all the other lights, gages, and indicators were working properly so I decided to just go with the flow so to speak and in the end it did bite me in the ass. Trying to clean all those contacts on plugs already put in place with the various items on the bike making them hard to get to is tough, so for anyone doing this I'd say to clean all the contacts in the wiring harness when it's off the bike and easy to handle. Having bad or suspect connectors in the wiring harness is like having plugged arteries in your body, the juice just doesn't flow as well as it should.
