Electrical issue

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Richard Simpson Mark II
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Re: Electrical issue

Post by Richard Simpson Mark II »

Had the starter motor off this pm.

It spins like a good un when connected to the little battery on my KTM 525.

Reinstalled it, and am recharging the little battery....there's just room to connect it over the battery in the Aprilia: we'll see if it can crank it tomorrow.

I took out the inspection bung in the side of the crankcase and (thankfully) could turn the engine over using a giant allen key, so having tried pretty much everything else, I'm left with the battery.
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Hugh
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Re: Electrical issue

Post by Hugh »

Greetings again,

I presume that the system on the bike is similar to the following generic pictures;
starter motor unit.jpg
starter motor unit.jpg (20.13 KiB) Viewed 1089 times
starter circuit.jpeg
starter circuit.jpeg (65.63 KiB) Viewed 1095 times
sprag clutch.jpg
sprag clutch.jpg (50.45 KiB) Viewed 1095 times
I know I'm teaching grandma to suck eggs here but somebody else might pick up some info/ideas too :idea:

Questions,

have you tested battery voltage static = 14.5v and under load drop to no lower than 11.5V ( I use a bulb as well and watch how bright or dim it goes)
battery voltage at solenoid
battery voltage at starter motor connection

remove starter motor - secure in vice or get a big lad to stand on it - connect to a slave battery and see if it turns - if it throws the big lad off then it probably is sound if not the might need further investigation (edited - forgot to say not to spin the motor for more than a second or two as the possible 'free' spinning speed can cause internal problems to a good motor)

can the engine be turned by hand - perhaps in gear rotating the rear wheel with spark plus removed
inspect sprag clutch/overrun gears and faces because if the starter was struggling in the past there could be physical damage to the gearing/faces

put the starter back into position, tape over the electric welly button and buy a kick start :lol:

TTFN

Hugh.
Richard Simpson Mark II
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Re: Electrical issue

Post by Richard Simpson Mark II »

That's pretty much it Hugh.

The motor spins when connected to a little battery (off the bike).

I was not inclined to blame the battery on the aprilia as it is a heavy-duty Yuasa purchased from AP Workshops and recommended as an upgrade on the standard part. It's been kept charged up using an Optimate.

But when you've eliminated all other possibilities, the remaining possibility, no matter how unlikely, must be the one.

I'm charging it with a conventional charger now, and will try another battery on the aprilia tomorrow.
catcitrus
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Re: Electrical issue

Post by catcitrus »

Here's a suggestion--with the starter on the bike disconnect the live feed from it. Then use a heavy jumper lead and go straight from the battery and touch the normal live feed into the starter---ignition off of course. This will test whether the starter has enough go to actually turn the engine and removes all other wiring, connectors etc from the test. There could be a bit of a flash when connected and remember that you are dealing with an unprotected feed and some pretty heavy current. The brushes may be good enough to spin the starter on the bench but not good enough to make decent contact and supply power when there is a load on it. I take no responsibility for this advice!
daveuprite
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Re: Electrical issue

Post by daveuprite »

catcitrus wrote: Tue Jul 20, 2021 9:31 am Here's a suggestion--with the starter on the bike disconnect the live feed from it. Then use a heavy jumper lead and go straight from the battery and touch the normal live feed into the starter---ignition off of course. This will test whether the starter has enough go to actually turn the engine and removes all other wiring, connectors etc from the test. There could be a bit of a flash when connected and remember that you are dealing with an unprotected feed and some pretty heavy current. The brushes may be good enough to spin the starter on the bench but not good enough to make decent contact and supply power when there is a load on it. I take no responsibility for this advice!
And enjoy your new hairstyle... :D
Richard Simpson Mark II
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Re: Electrical issue

Post by Richard Simpson Mark II »

I've got a pacemaker, so electric shocks are to be avoided!

About the venture into the garage!
Richard Simpson Mark II
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Re: Electrical issue

Post by Richard Simpson Mark II »

"I don't BELIEVE it!"

It was the battery: a heavy-duty Yuasa upgrade recommended and supplied by AP Workshops, and fitted just over two years ago.

I bit the bullet, dug the Odyssey PC310 out from under the KTM 950 engine where is has lurked for 7 years, cleaned all the accumulated filth off it, connected it to the Aprilia and it fired like a good 'un.

The Yuasa is going to the dump where it belongs, and a replacement Odyssey has been ordered. When it comes to batteries, British is best!
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Re: Electrical issue

Post by mechanic »

I’ve just purchased a new yuasa battery. Showed 7.5 volts when I received it, after 36 hrs on optimate still wouldn’t make 12+ volts. The suppliers were very good and exchanged it on overnight carrier the next day. They did say, now and again they get a dud one from new.
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Re: Electrical issue

Post by daveuprite »

Richard Simpson Mark II wrote: Tue Jul 20, 2021 2:43 pm "I don't BELIEVE it!"

It was the battery: a heavy-duty Yuasa upgrade recommended and supplied by AP Workshops, and fitted just over two years ago.

I bit the bullet, dug the Odyssey PC310 out from under the KTM 950 engine where is has lurked for 7 years, cleaned all the accumulated filth off it, connected it to the Aprilia and it fired like a good 'un.

The Yuasa is going to the dump where it belongs, and a replacement Odyssey has been ordered. When it comes to batteries, British is best!
Hi Richard - I just looked up that Odyssey battery - looks really good - pricey but very high cranking amps which is useful for italian high compression V-twins. What do you use to charge / trickle charge it ?
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Re: Electrical issue

Post by Richard Simpson Mark II »

Just an Optimate...I've now got those batteries in the KTM 950 and the Aprilia. They deliver 330w for five seconds: and if that doesn't start it, nothing will.
They are basically a mini version of the batteries you will find in a forklift: built to stand repeated charging and discharging. There's also a version for heavy trucks...a lot of the trucks that used to go to the former Soviet Union etc used to use them. Plus they are used in racecars etc.
I get mine from Demon Tweaks: next day delivery.
The one that was in the KTM and is now in the Aprilia must be seven years old. The battery on the KTM gets bombarded with dust and water, it's under the engine!
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