COILS?

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Crusher

COILS?

Post by Crusher »

Ive done the wiring upgrade,new battery,new plugs and have gone over all the earths 2 make sure all is ok. The problem im having is that there is good spark and then there is no spark. I have a multimeter which gives me a reading of 11.95v at battery and 11.85 between the relay and coils with switch on, so is it the coils or the the regulator/rectifier which either I dont no how 2 test. The reg/rectifier does not look original [SH673-12] as it came with bike and looks like someone slotted the holes, coils are Kokusan and ive always disconected battery when working on this project :banghead: and I have 2 addmit it has become abit overwelming and I would appreciate any info cheers Paul :dunno: PS when I did have it running on both cylinders and also with just key on the coils got quite warm hope this helps.
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ducinthebay
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Re: COILS?

Post by ducinthebay »

From your post, I'm assuming the bike is not running currently, is that right?
A fully charged battery should be almost 14 volts (13+) so if you don't have that, your battery isn't fully charged. Most motorcycle charging system will not do a good job of charging up a battery, and its best to put a charger on it to get it up. While its running, (if it runs) you should get very close to 14 v at the battery above 1800 rpm.

The drop of 0.1v is not too bad. In the stock system, a drop of a few volts was likely at the coils, so you are doing much better.

Coils do wear out over time. The stock coils were adequate, but there are many other coils that are better. Get a set of Dyna Coils to be sure. Coils often fail when warm. With failing coils, the bike will run fine for a bit, then run badly when warm. Part of the problem with the stock coils is that the high tension leads could not be replaced. Cut off an inch and screw your sparkplug caps back on and see if that helps any.

An intermittent problem is always very difficult to trace down, especially electrical ones over the web. Check all grounds and connections. Clean them and put some dielectric grease on them (silicone grease).

Keep us posted.
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.
Tamburinifan
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Re: COILS?

Post by Tamburinifan »

You first have to find out what part is failing,
pickups, coils or Kokusan ignition boxes.

Of course you hae fresh plugs?
Gert

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paso750
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Re: COILS?

Post by paso750 »

is there really no spark or does the engine have dropouts ? If it`s the later I`d also check carb synchronization.

G.
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higgy
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Re: COILS?

Post by higgy »

Leaky Idle jet o-rings can seem like coil drop outs as well...........choking while it drops out will improve and point to this fault. Easy way to diagnose :thumbup:
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There's no problem so bad that a little fixing can't make it worse! : )
Electrocuted Birds Are Bursting Into Flames and Starting Wildfires :roll:
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Crusher

Re: COILS?

Post by Crusher »

Thanks for all the info,have charged battery, new orings on idle jets and still not firing although I have a more consisstent spark it still looks like the front cylinder is down some as I checked with plugs out first 2 c what it was like so back 2 the drawing board.The question I ask is how do u check the ignition boxes and pick ups 2 c if they are faulty :wacko: as im not that clever when it comes 2 electrics so cheers 2all that have put input already as it has been much apreciated. Im also waitng on set of monster coils from a 2009 696 1100? which I brought on ebay and now been told they might not b ok anyway enough of my woes :banghead: time 4 a :beer:
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Foxtee
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Re: COILS?

Post by Foxtee »

If you are getting a spark on 1 cylinder then at least 1 plug/coil/ignition box is working .
swap them over one at a time too see if there is change.
If no change then the problem could be between the pickup and ignition box check the wiring for breaks to earth, haven´t seen any thing on this forum about faulty pickups.
I replaced the coils on my 750 with a pair off a 750 monster (carb not injected) made a big difference , got them off ebay for $100 NZ including shipping , have seen them pop up on trade me for $120-130
Hope this helps Merry Xmas :beer:
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higgy
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Re: COILS?

Post by higgy »

Check those plug wires as well. any signs of discoloration ( grayish white marks) usually means a leak.
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
Electrocuted Birds Are Bursting Into Flames and Starting Wildfires :roll:
88 750
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92 907ie
Mc tool
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Re: COILS?

Post by Mc tool »

Crusher , when you fitted the relays , did you run a new power wire from the battery ( or main fuse ) to the relay ?. The whole idea is to provide as short a passage as possible for the power to travel from the batt to the coils, IE not thru the ign sw . If you have used the original power feed that might be the problem . These bikes IMHO have shit wiring , check the wires and crimped on terminals at both the ignition switch and the right hand switch block multi-pin plug by holding the terminal and give the wires a good yank ( oops there we go again :P :P ) the kill switch is in series with the coils , when you switch the kill switch off it cuts the power to the coils , and a bad connection here could explain the fault . The fact that you have battery voltage ( sort of ) at the coils might not mean much depending on how did the test . If you disconnected the coils from the power b4 testing ,the power wire might show battery voltage , the idea is to test with the coils connected that way the power feed is under load because the coils are draining power ( you should connect a temp earth and only turn power on long enough to do test, 30 sec ), this will cause any bad connection to fail ( it may get hot too ) where as testing unloaded , the bad connection can flow enough power for a multimeter to see battery voltage ( multimeters use f all power ) good luck .Another thing to consider is that a faulty coil or one with a faulty power supply may well throw a spark while holding the plug against the cylinder , but fail , possibly intermitantly , while under ( cylinder ) compression .If closing the plug gaps to some stupidly small gap improves the situation this could point to either a weak coil or a weak power supply
Hamish
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paso750
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Re: COILS?

Post by paso750 »

by holding the terminal and give the wires a good yank
how can you recommend that ?! That´s what a multimeter was invented for and every part can be disassembled to check thoroughly.
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Re: COILS?

Post by higgy »

A voltage drop test will find any poor connection. Like G stated, all you need is a way too measure voltage. Even a cheap 10 dollar volt meter will perform this kind of test. No need to risk a fire or damage to all your precious and hard to find parts. Even a complete electrical neophyte can find very good info on the web on exactly how to do this sort of test.
Here is a very good article on how it is done. It is one of the easiest and most effective ways to find any problem in any circuit. All you have to do is turn the circuit on.
http://www.aa1car.com/library/voltage_drop_testing.htm
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
Electrocuted Birds Are Bursting Into Flames and Starting Wildfires :roll:
88 750
90 906
92 907ie
Mc tool
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Re: COILS?

Post by Mc tool »

paso750 wrote:
by holding the terminal and give the wires a good yank
how can you recommend that ?!
Easily .Sometimes the terminals fitted to the copper conductors are over crimped ( for want of a better word ) and the conductor is damaged and in time / vibration will break . The molux connectors used on the paso have 2 crimps , the first crimps the conductor only , the second crimps the insulation as well . the conductors break between the 2 crimps leaving the connection LOOKING ok , they can often pass a continuity test too , but try and drag a bit of current thru it.... as Higgy sez a volt drop test is the best way to find this ,( but I have found that some people struggle to grasp this volt drop thing )if you are looking blindly for an unknown fault , but if you have seen the same fault repeatedly ( 300v dc ECS motors )...... put it this way , by the time the apprentice has found his multimeter I have already reterminated the wire . Maybe I should have said " a gentle tug " but that didnt sound as funny to me , and if the plastic insulation stretches just by the terminal... broken wire . DC current will often arc and spark its way thru this break in the conductor ( unseen , inside the insulation ) much better than AC and often I have found that to really nail the fault this gentle pull on the wire will completely sever the connection.I have seen this type of fault pass continuity and volt drop tests only to fail again later. I know it seems silly to be pulling on wires when I carry 3 grands worth of meters with me, sometimes its just quicker
OR
maybe Im just a dumbass
I wish I was young again............Id be heaps smarter than last time
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Re: COILS?

Post by higgy »

McTool
You are no where near a dumbass, same planet but different address :lol: :lol: :lol:
For anyone with experience in such matters, there is always a fast way to get to the root of an issue
Is it the ecm? get your BFS out and give the friggin ECM a love tap. quickest way to find an intermitant electronic issue. Works on most sensors, senders and pickups and control modules especially the ones that pass every other test known to man :shock:
DC supply issue, sure give the wire a tug, but tug on the wrong wire and find yourself on the wrong end of a 24volt dc problem and it is most decidely is going to ruin your day and I do try not to send more than one rookie to the hospitol per week, my manager says it is not cost effective training these days :evil:
Of course you and I know real men find 60Hz ac problems while standing in the deep end of their pool but not till that 6 pack is killed off. Does not mean I would reccomend it for everyone :mrgreen: Besides that 3 grand worth of meters is all the way out in the truck and I'm gettin hungry

I for one enjoy all your posts, they always invoke a fond memory of days gone by and hard earned lessons, scars and all :thumbup: :thumbup:
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
Electrocuted Birds Are Bursting Into Flames and Starting Wildfires :roll:
88 750
90 906
92 907ie
Mc tool
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Posts: 1985
Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
Location: Riverton New Zealand

Re: COILS?

Post by Mc tool »

:P :P :lol: an any how , Mr paso 750, did you know that the Ducati factory was once world renown for making radio's and electronic equipment , and that we probly wouldn't even be having this discussion about ducati electrical reliability if "somebody" hadn't bombed shit outa the place in 1944 :lol: :lol: :lol: :lol: :lol: prolapsed ileostomy :lol: :lol: :lol:
I wish I was young again............Id be heaps smarter than last time
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