750 sport charging system

discussion about the 750 Sport and '89/'90 900SS, which share many mechanicals with the Paso series
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jetboy
Posts: 86
Joined: Sat Nov 08, 2008 3:51 am
model: 750 Sport
year: 1990
Location: oakland, ca, usa

Re: 750 sport charging system

Post by jetboy »

thanks for the write up. this should be put into the FAQ

i also have a few electrical issues, so i ordered a r/r off ebay, from a monster. i was just living with it as it sort of works-- the battery doesn't drain from use, but it doesn't charge either. Ive been using a tender to keep it happy but recently i bought some LED turn signals and they wont work as they seem to need a full 12v before they turn on, and im only getting 10! so hopefully a stronger r/r and some cleaning of the wires will fix that.
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jcslocum
paso grand pooh-bah
Posts: 1714
Joined: Mon Jul 19, 2004 12:00 am
model: 750 Paso
year: 1988
Location: Eastern Shore, MD
Contact:

Re: 750 sport charging system

Post by jcslocum »

jetboy wrote:thanks for the write up. this should be put into the FAQ

Any member can put a post into the FAQ and link to the thread. It's our FAQ to build.
blaster

Re: 750 sport charging system

Post by blaster »

on my last post, i stated that ducati had a fix for the main fuse holder. after rereading jcslocum's post on this subject, i saw he was refering to 916's. the fix was for 750 sports. sorry, i think i left the garage door down too long with the motor running. blaster
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jetboy
Posts: 86
Joined: Sat Nov 08, 2008 3:51 am
model: 750 Sport
year: 1990
Location: oakland, ca, usa

Re: 750 sport charging system

Post by jetboy »

In some of the fastest shipping ive seen the r/r i ordered saturday night arrived monday afternoon.

so this morning i went at installing it and found some terribly shoddy work by the PO- not only was the r/r some random aftermarket job with even lighter gauge wire than even the before mentioned less than great yellows from the stator, but he had spliced those wires to extension wires, and then those wires into the loom/stator wires. so every wire had not one connector, but 2, noneof which were soldered, and yes, the yellows were all melted at one of the junctions. to make matters worse, he had spliced an even lighter gauge wire onto the grounds, and then "grounded" that to the bolt holding the r/r on BUT - the r/r bolt is matched to a insert nut with a RUBBER gasket around it.

well, anyway, i threw that giant mess in the trash and soldered the r/r from the monster in like was recommended - and cleaned up the grounds etc. I finished about 10 minutes after i needed to leave for work, so i didnt have a chance to really test it. but i did have time to fire it up and try the LED blinkers-- which now work! so they must be getting at least 12v - which is at least 2 v better than i was getting before.
User avatar
jcslocum
paso grand pooh-bah
Posts: 1714
Joined: Mon Jul 19, 2004 12:00 am
model: 750 Paso
year: 1988
Location: Eastern Shore, MD
Contact:

Re: 750 sport charging system

Post by jcslocum »

Wow, what a MESS!!! Amazing how much hard can go intodoing something the WRONG way when it would have been no more work to do it right.

My dad used to say: "there's never time to do it right, but always time to do it over". He had a few other good one's but they don't really apply here....
btlofrum

Re: 750 sport charging system

Post by btlofrum »

Well, it took about three weeks, but I finally found time to rip out the old regulator and put a new one in. The old one just wasn't charging, so I bought an aftermarket one. (I've been using the same one on my '92 SS since last year without any issues...just a few thousand miles though).

When I pulled out the wiring, the connectors between the yellow wires from the alternator and the yellow wires from the OEM RR were melted together. I cut off the old connector until the wires were clean, and proceeded from there. I had to run a new ground to the battery, but she's charging properly now.

I yanked the belt covers, since I had the fairings off. PO said the belts/valves were done recently. Belts look clean enough and are correctly tensioned.

That leaves me with the speedo drive to address-since the ratio between the speedo drive and the speedo is out of whack. I have a few spares to try. Tomorrow.

Once I finish lunch, I'll take a ride. I need to get the bike reinspected. I failed two weeks back since the front brake lever switch wasn't activating the stop light. Since the front end is off an SS and the master cylinder/controls are off an SS, and there's a microswitch that activates the brakelight. Bought some aftermarket ones, since Ducati wanted $40 for a switch, and the used parts dealers wanted about $30.
User avatar
jetboy
Posts: 86
Joined: Sat Nov 08, 2008 3:51 am
model: 750 Sport
year: 1990
Location: oakland, ca, usa

Re: 750 sport charging system

Post by jetboy »

i put an aftermarket speedo on mine and its slightly out of whack as well, so i was thinking about getting an inline ratio adapter off the bay. so if none of yours work out, you can pick the one you like and adjust it.

I still have to calibrate exactly how far mine is off before i get the adapter - now im estimating about 20% slower just from odometer - i drove about 20 miles and it said i only did 16.4
btlofrum

Re: 750 sport charging system

Post by btlofrum »

Do you have a link for one of those? I'm not familiar with them.

My Monster is 10% optimistic, and has been since day 1 (purchased new by me). And that includes the odo and the speedo.

The Veglia speedo on the Sport (with an SS front end) is the same as the Veglia speedo on my '92 SS, so I'm hopeful that duplicating that speedo drive will work. Unless the speedos just look similar, and have different gearing inside.

At any rate, the PO gave me 3 or 4 with the bike, although some have the smaller axle for the old front set up. And I have a spare for my Monster. Hopefully something works. Hardest part, really, is finding a measured mile to test, since I don't have a portable GPS.

Ben
pat

Re: 750 sport charging system

Post by pat »

Hi all,

I have a 93 ducati Monster 900, my battery recently exploded, i will now be replacing it with a sealed type however i suspect the reason it did despite the very hot weather where i live is a faulty regulator which is over charging the battery. I'm on the verge of ordering a new one as the old one when i tested it didn't give the readings my haynes says it should. My haynes also mentions that if i replace the regulator then i should replace the stator as they were both uprated however while the regulator seems fairly easy to get the stator isn't, any ideas on how important this actualy is? i will not be replacing the regulator with the oem part but an aftermarket although i'm sure this is uprated as well. My thinking and i'm no expert in this is that if i replace the regulator and not the stator then the stator will still give off a lower power rating that my new regulator can handle however if i was replacing the stator and not the regulator then it would blow the regulator which would be a bad idea.

any help appreciated
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ducinthebay
paso grand pooh-bah
Posts: 1323
Joined: Sat Sep 03, 2005 12:00 am
model: 750 Sport
year: 1990
Location: SF Bay Area

Re: 750 sport charging system

Post by ducinthebay »

No need to replace the stator, unless its toast. Your Haynes manual is a bit misguided. Put in a regulator, and confirm that everything is good, and go for a ride. Spend your money on gas, while you still can.

Cheers,
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.
pat

Re: 750 sport charging system

Post by pat »

Hi thanks, gas is cheap here in Dubai so no problems there but parts are! glad to see my thinking isn't entirely off, will give it a shot, cheers
User avatar
jcslocum
paso grand pooh-bah
Posts: 1714
Joined: Mon Jul 19, 2004 12:00 am
model: 750 Paso
year: 1988
Location: Eastern Shore, MD
Contact:

Re: 750 sport charging system

Post by jcslocum »

Pat,

You need to find and clean (sandpaper/scotchbrite) every ground/earth on the bike when you have the body panels off. The regulator also needs a good ground, if it doesn't have one already. A bad ground will make the regulator "think" that the battery is low and it will try to charge the hell out of it. This can blow up the battery and fry the regulator.

You should go over all of the connectors and make sure they are clean and not corroded. Make sure to carefully check the 2 wires that come from the stator. they have connectors too that need to be carefully checked.

Good luck!
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