XS750

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Tom

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Jun 22, 2020, 10:30:49 PM6/22/20
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A young friend has a XS750 3 cylinder. He can't get spark. I'm going to help but I really don't want to get stuck with a long job. Any advise from experience?

Thanks,
Tom

Andrew Dunham

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Jun 22, 2020, 10:44:41 PM6/22/20
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Hi Tom, 

Good to hear from you! Any idea what year the bike is? In my short amount of reading, it seems like the later bikes ('78+) have a CDI box and quite a few have gone bad. I assume you mean they can't get spark on any of them. Otherwise, the normal points stuff; and the easy to forget things like battery voltage.

Tom

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Jun 23, 2020, 8:12:50 AM6/23/20
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Hi Andy,

I think it is the TCI box and yes I believe it is a '78. Eli has two boxes but neither work as yet. I'm thinking it could have a similar ignition as the later XS650. I just hope it isn't like the SR 500. I never did figure that out. I'll have to look at it when I visit. Eli has a metals shop close to Sideswipe so I thought it might be a good garage day for him, that could be fun.

TG

Grafton Swickard

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Jun 23, 2020, 9:03:30 AM6/23/20
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Unfortunately, I haven't got as far as this particular fight with my XS750, but if Andrew's right and the CDI box has gone bad, there are several available on ebay, currently, starting at $60 and going up from there. You might also point him to mikesxs.net - they're the best source I've found for XS parts, in general, but they don't seem to have the CDI boxes.

On Mon, Jun 22, 2020 at 10:44 PM Andrew Dunham <andrew...@gmail.com> wrote:
Hi Tom, 

Good to hear from you! Any idea what year the bike is? In my short amount of reading, it seems like the later bikes ('78+) have a CDI box and quite a few have gone bad. I assume you mean they can't get spark on any of them. Otherwise, the normal points stuff; and the easy to forget things like battery voltage.

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Wade Dunham

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Jun 23, 2020, 9:34:01 AM6/23/20
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There is (or was) a guy on the YAM650 mailing list that repaired TCI boxes for XS650's. His name is Rick Miller (rickt...@gmail.com). He may still be around. Are you still on the YAM650 list, Tom?

You had me at "metal shop" but "close to Sideswipe" sealed the deal!  :-)

Wade Dunham

kevineleven

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Jun 29, 2020, 6:44:48 AM6/29/20
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I have a complete but Unassembled xs650 here, you can borrow any parts you need for troubleshooting

Tom

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Jun 29, 2020, 11:25:54 AM6/29/20
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Hey Kev, What year is your XS650? Wade and I both have '77 650's.

Thanks for the offer of parts but the XS750 is a triple. I went to Eli's shop and it seems the problem is bad TCI boxes, both didn't work. I looked at the wiring and we tested potential flaws but everything seems to be in order. I suggested the power transistors need replaced. The boxes have the board permanetly attached to the box top so Eli will need to cut the top off one of them. If it can be fixed, the top can be glued back on.

Tom
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Wade Dunham

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Jun 29, 2020, 3:59:32 PM6/29/20
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Tom:

Did he have power to the TCI box? Seems like you said he made his own wiring harness. Here is a diagram for an XS850. I've read that they are very similar to the late XS750 with TCI. This may help in determining if he has the "must have" circuits.

850g_wiring.jpeg

This a a link to troubleshooting the TCI ignition on an XS650, the basic concepts may apply:

Wade Dunham

Tom

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Jun 30, 2020, 7:18:22 AM6/30/20
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It appeared the harness was merely stripped so all the original ignition wiring is in place. Eli tested each wire. Tickled each coil and got spark. Tested resistance each coil and the three trigger coils. New fully charged battery was put on the charger while we worked. No spark. I was thinking Eli missed a ground but he seemed to have all the bases covered before I got there.

Tom
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Wade Dunham

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Jun 30, 2020, 8:13:48 AM6/30/20
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Tom:

Sounds like you and Eli have it covered. Borrowing a known good box from someone local to swap in would be ideal but would probably be difficult to find. If Eli is unable to diagnose the problem with the box, Rick Miller on the YAM650 list is still there and still repairing XS650 boxes. He may be able to help. As Grafton mentioned, there are a few on eBay listed as "tested good" or "pulled from a running bike". One of those might be worth a try if the seller has very good feedback and would issue a refund if it didn't work.

Wade Dunham

Wade Dunham

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Jul 1, 2020, 12:30:47 PM7/1/20
to Eli Secrest, Columbus VinMoto
I hope that works for you, Eli. It seems like you and Tom did a good job in narrowing down the cause of the problem. Let us know what happens. I haven't seen an XS750 for a while, so post a pic of your bike if you get a chance. Thanks.

Wade Dunham

On Wed, Jul 1, 2020 at 11:31 AM Eli Secrest <elisinge...@gmail.com> wrote:

Hey! Yea, I found a cdi on ebay that said it was tested good, it should arrive this week and I’ll toss everything together and hope for lightning! Hopefully it’ll work and I won’t continue to have a big brick but only time will tell. Thanks!

 

Sent from Mail for Windows 10

 

From: Wade Dunham
Sent: Tuesday, June 30, 2020 8:13 AM
To: Columbus VinMoto
Cc: Eli
Subject: Re: [Co-OhVinmoto] XS750

 

Tom:

 

Sounds like you and Eli have it covered. Borrowing a known good box from someone local to swap in would be ideal but would probably be difficult to find. If Eli is unable to diagnose the problem with the box, Rick Miller on the YAM650 list is still there and still repairing XS650 boxes. He may be able to help. As Grafton mentioned, there are a few on eBay listed as "tested good" or "pulled from a running bike". One of those might be worth a try if the seller has very good feedback and would issue a refund if it didn't work.

 

Wade Dunham

 

 

On Tue, Jun 30, 2020 at 7:18 AM Tom <tomte...@hotmail.com> wrote:

It appeared the harness was merely stripped so all the original ignition wiring is in place. Eli tested each wire. Tickled each coil and got spark. Tested resistance each coil and the three trigger coils. New fully charged battery was put on the charger while we worked. No spark. I was thinking Eli missed a ground but he seemed to have all the bases covered before I got there.

Tom



-------- Original message --------
From: Wade Dunham <waded...@gmail.com>
Date: 06/29/2020 3:59 PM (GMT-05:00)
To: Columbus VinMoto <co-ohv...@googlegroups.com>
Subject: Re: [Co-OhVinmoto] XS750

Tom:

 

Did he have power to the TCI box? Seems like you said he made his own wiring harness. Here is a diagram for an XS850. I've read that they are very similar to the late XS750 with TCI. This may help in determining if he has the "must have" circuits.

 

 

This a a link to troubleshooting the TCI ignition on an XS650, the basic concepts may apply:

 

Wade Dunham

 

kevineleven

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Jul 5, 2020, 7:45:39 PM7/5/20
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It’s an 81 I got from a college classmate who’s wig came down with a horrible case of the babies, 2 at once. It’s supposed to be a project for my son but his 19 year old self isn’t really motivated to wrench currently.

kevineleven

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Jul 5, 2020, 7:46:30 PM7/5/20
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Wife. His wig is fine.

cle...@gmail.com

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Jul 5, 2020, 7:55:51 PM7/5/20
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Funny guy.

Sent from my iPad

> On Jul 5, 2020, at 7:46 PM, kevineleven <ke...@70-71.com> wrote:
>
> Wife. His wig is fine.
>
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