Posted by Totalrod2 on June 20, 2006, 6:42 pm
I've owned my Virago XV700 for a few months now and have experienced
all the typical problems associated with these bikes (most noteably the
usual starter problems and the rear cylinder not firing). I've already
installed a new starter. A novice can do this in a couple of hours, or
less. Last month the rear cylinder fired occasionally, but now it never
does. Sometimes the damn bike won't even start at all! It does have a
new coil installed (though not by me). I checked to see if it was
getting a spark to the rear cylinder (and it wasn't) which leads me to
believe it's the TCI box. I've heard guys on other forums say it's
because of hairline cracks in the board which expand and contract with
the weather/humidity. But before I spend alot of money on a new box,
I'm going to take the path less traveled. I read somewhere that the two
D1071 transistors (which essentially act as relays for the cylinders)
sometimes wear out. They're only a buck, so I ordered 4 of them from
Mouser electronics. The D1071 transistors can be replaced with BU806
(Fairchild part number) or RCA part # SK9431. Hopefully I'll be able to
have them installed by this weekend. I may as well replace both while
I'm in there. If this works, I'll have spent about $5 on parts, versus
over $300 for a new TCI box.....which may not have even been neccesary
in the first place! I'll keep y'all posted.
Bryan Lord
Posted by tschw10117 on June 20, 2006, 9:45 pm
Bryan, please do... I'm resurrecting the same bike right now. I'll be
glad to share what I'm going thru as well, including my starter
experiences.
Transistors don't "wear out", typically they either work -- or they
don't. Circuit board cracks on the other hand, can be both intermittent
-- and repaired.
Terry.
Totalrod2@aol.com wrote:
> I've owned my Virago XV700 for a few months now and have experienced
> all the typical problems associated with these bikes (most noteably the
> usual starter problems and the rear cylinder not firing). I've already
> installed a new starter. A novice can do this in a couple of hours, or
> less. Last month the rear cylinder fired occasionally, but now it never
> does. Sometimes the damn bike won't even start at all! It does have a
> new coil installed (though not by me). I checked to see if it was
> getting a spark to the rear cylinder (and it wasn't) which leads me to
> believe it's the TCI box. I've heard guys on other forums say it's
> because of hairline cracks in the board which expand and contract with
> the weather/humidity. But before I spend alot of money on a new box,
> I'm going to take the path less traveled. I read somewhere that the two
> D1071 transistors (which essentially act as relays for the cylinders)
> sometimes wear out. They're only a buck, so I ordered 4 of them from
> Mouser electronics. The D1071 transistors can be replaced with BU806
> (Fairchild part number) or RCA part # SK9431. Hopefully I'll be able to
> have them installed by this weekend. I may as well replace both while
> I'm in there. If this works, I'll have spent about $5 on parts, versus
> over $300 for a new TCI box.....which may not have even been neccesary
> in the first place! I'll keep y'all posted.
> Bryan Lord
Posted by Bryan on June 22, 2006, 1:21 am
have you gotten into delphi forums? they have 1 on virago's. free
info. some of the guys know them bikes inside out.
www.delphiforums.com free to join search virago owner's group
bry
Posted by Totalrod2 on June 22, 2006, 6:52 pm
Bryan wrote:
> have you gotten into delphi forums? they have 1 on virago's. free
> info. some of the guys know them bikes inside out.
> www.delphiforums.com free to join search virago owner's group
> bry
Yes, I posted this same thread over at the Virago Owners Club Forum. I
figured if this works, it's probably a good bit of knowledge to pass
along. I tested one of those transistors and the Base-Emitter (BE)
junction was bad. So I'll just replace them both, it can't hurt. I
ordered them from Mouser electronics on Monday. Hope to have them by
this weekend, but we'll see. Definately by next week. Thank God I have
a truck.
Bryan Lord
Posted by Totalrod2 on June 24, 2006, 3:12 pm
Well, the BU806 transistors came on Friday and I installed them on the
TCI board today. EUREKA!.....The rear cylinder is firing. Actually, my
bike is running better than ever. It's never fired right up before.
Usually I had to turn it over a couple of times. I'd definately have to
recommend this inexpensive little repair to anyone who's thinking their
entire TCI box is shot. At least in my case, replacing those 2
switching transistors did the trick. I know some people have had the
rear cylinder quit firing after the bike was warmed up and the
tachometer sometimes goes screwy. That was NOT my case. A case like
that could mean a loose or corroded connection (probably the fuse) and
the TCI box "looses it's mind" from not getting enough juice to it. All
my connections were clean and my rear cylinder was dead from the moment
I started the bike, so I knew that wasn't the problem.
Anyhow, I just thought I'd let y'all know I got it running.
Bryan Lord
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> all the typical problems associated with these bikes (most noteably the
> usual starter problems and the rear cylinder not firing). I've already
> installed a new starter. A novice can do this in a couple of hours, or
> less. Last month the rear cylinder fired occasionally, but now it never
> does. Sometimes the damn bike won't even start at all! It does have a
> new coil installed (though not by me). I checked to see if it was
> getting a spark to the rear cylinder (and it wasn't) which leads me to
> believe it's the TCI box. I've heard guys on other forums say it's
> because of hairline cracks in the board which expand and contract with
> the weather/humidity. But before I spend alot of money on a new box,
> I'm going to take the path less traveled. I read somewhere that the two
> D1071 transistors (which essentially act as relays for the cylinders)
> sometimes wear out. They're only a buck, so I ordered 4 of them from
> Mouser electronics. The D1071 transistors can be replaced with BU806
> (Fairchild part number) or RCA part # SK9431. Hopefully I'll be able to
> have them installed by this weekend. I may as well replace both while
> I'm in there. If this works, I'll have spent about $5 on parts, versus
> over $300 for a new TCI box.....which may not have even been neccesary
> in the first place! I'll keep y'all posted.
> Bryan Lord