Old Yamaha diodes

I've seen some posts reguarding the diode blocks for the sidestand saftey. I explained that these diodes corrode over the years and break. The pics are the diodes in my Venture ignition module, they are corroded from the inside working its way out. Give them a little more time and they will break, who knows what would happen then. The bike was showing signs of ignition problems, the occational miss and loss of power told me something was up.
The worst one is pointed out in the first pic. There are 6 more that are showing signs of internal corrosion and can be seen in the larger pic.
I'll replace these with new ones in the next day or so with RadioShack 1N4001 diodes. I'll post some pics when I am done.
Glad I cought it before it left me stranded.

 

Well crap Lew. You've convinced me I need to tear into mine this winter. Fuel mileage is poor, idles great and plugs look good. Maybe I'll find a problem in the black box.

 

Might be worth looking into MiCarl, The mileage on my V-Max sucked until I rebuilt the carbs. 20 mpg before and 38 mpg after. The PO had put silicone in the main air jet hole on 2 carbs because it was leaking fuel. Stupid people irritate me.
I replaced all 8 diodes last night. 4 of them crumbled when I de-soldered them from the board. I think they would have broke if I hid a hard bump in the road. The other 4 held together while removing them. Soldered in the new diodes and test ran the bike for a few minutes. It did start easier and the stumble durring acceleration was gone. I'll clean and paint the brackets tonight and road test this weekend.

 

Thanks for the heads up on this, I'm just working my way through the electrics on my 900, how about the diode between the oil level and clutch/neutral switches? It's not on the board but is a plug in affair in a potted can with a resistor as well. I was thinking of replacing that as well.

 

Hey Lew:

Since I'm not much on electrical components and have never seen a diode like that can you guide me on how replacement diodes are oriented? Does the painted end of a 1N4001 go toward the blue on the old diode? Or does the painted end go toward the white with blue dot end?

Thanks!

 

Yes MiCarl, the painted end of the diode will match the stripe on the new one. There are the typical diode signs on the Yamaha circuit board( arrow )
looks like ---/<---.
Just match them up. The diode pack also has the same sign.

iandmac:
The diode block you are refering to is the one most XJ folks deal with. I have replaced the diodes in those with the same ones. They suffer from the same problems. So far I have fixed the ones in my V-max and XJ11. So far the cost for all of them has been less than 5$

 

Just to clarify - are the "same ones" the 1N4001 diodes or the 1N5402 diodes used in the side stand safety switch diode block?

And are the ignition diodes the "blue/white ball" items on the circuit board (some of those resistors look dicey too)?

 

Yes the blue/white balls and the diodes. The resistors are covered with a wax that was poured on . It looks nasty but the devices in there are OK.
For the puropes the diodes are use for they both can interchange.
The differences are
1N4001- 1 amp 50 v
1N5402 - 3 amp 200 v
The voltage rating is the maximum reverse voltage the diode can handle.
The sidestand circuit could pull close to 1 amp so I used the 3 amp diodes in mine just to be safe. The original ones are 1 amp.
The ignition module also uses a 1 amp diode, the 3 amp ones won't fit in there so the 1 amp diodes went back in place.

 

cool! Finally found the "thrifty electrical genius" topic i have been looking for.Hope my question isn't too far off. I am trying to fix my rect/regulator by soldering inline Diodes and possibly Led's to indicate that they are working.
Bike is xj550 stripped to minimum wiring.

1. Which Diodes and/or LED's would be suitable?
2. What is the proper orientation of these.
3. Is there any minimum wiring diagrams that show the polarity or "direction of flow" to and from the Rect./Regulator?

thanks, please excuse my butting in your topic.

 

Remo,
This should really be posted in XJ Chat (or maybe XJ Modifications) as you are talking about an XJ bike charging issue (with a minimal wiring harness). The XJs use an "excited field" alternator which has carbon brushes (that need to be periodically replaced) riding on slip rings (that need to be cleaned periodically). The bike's regulator/rectifier unit is fairly trouble-free (usual point of failure is the connection plug to the alternator wires). Replacing it with some home-brew set of high-amperage diodes is a waste of effort (IMO). If you suspect a bad reg/rec, do the charging system tests and check your plugs, alternator brushes/slip rings, and battery first. If you want to install some LED item, I'd recommend a charging level LED array (run off the ignition switch) so you can see at a glance if your system is working properly. You really don't need to see if each diode in the rectifier circuit is working.

 

These pics are from a TCI, they typically fail from corrosion of the diodes in them. It is worth looking into because they are expensive to replace but sometimes inexpensive to repair. The regulator/rectifiers are not too expensive to replace. Most of them are sealed in epoxy and are almost impossible to get into without breaking them. New ones are a better option.

 

zap thanks for the info, turns out I stumbled on a local parts trade thx .peace

 

oh and as far as the rebuild of the tci's goes yes they are a pain even with phenomenal mc gyver skills a new part is the way to go. however there is a modification for the gpz550 made out of two GM HEI modules with diodes and resistors inline and such. so there has to be another way to do this with xj's as well.just waiting on the right electrical pioneer.