Topic: Too hell with these spark units Update: Fixed

[speedy gonzalais]

Ok im stepping out of my league here but it needs to be done, Im fed up with the spark units on my 650 the old ones overheated so have the new ones .
Ive replaced the harness gone over the whole thing and cant find anything wrong with it the altenator is good the coils are good so is the regulator/rectifier no bad earths or shorts but the units keep over heating eventualy draining the battery whilst riding till the bike dies i know it aint the battery/s cause i got 2 new ones the both wont last the day im gettin a good 14v going to the battery so its got to be these units. To cut a long story short can they be bypassed?

[kslrr]

No, they cannot be bypassed. They are what send the voltage pulse to the coils. I wonder if they could be replaced with GM units.

http://www.mynode.com/2wheel/?t=simple.html&v=hei/index.html

[speedy gonzalais]

i havnt got a points ignition its cdi ive read that the spark units supply the coils with a constant voltage keeping them charged all the time ive also read this is a bit of a waste of power ive heard verry little about bikes running with out them but have heard its possible maybe i heard wrong surely theres got to be a better ignition system out there?

[kslrr]

Ok, you know more than I do about the 650. Always happy to learn.  However, You can't run without them because you need something to "break" the voltage that then causes the field to calapse. Just like the old mechanical points do.  So maybe Hondaman's ignition box would work. It would carry the current saving the spark units.

[speedy gonzalais]

hondamans ignition box? is that some one on here ? that setup on the link is good but is for a points ignition not sure it works with mine.

[MJL]

http://forums.sohc4.net/index.php?topic=40485.0

[eldar]

from what I understand, the hondaman unit is only for points. I may be wrong since I do not have one. Drop him a PM and see.

[troppo]

from what I understand, the hondaman unit is only for points. I may be wrong since I do not have one. Drop him a PM and see.

Yep, hondamans unit is for a points ignition

[Hush]

Hey Dids, old man Honda created these things to work and work they do on most bikes.
You have "a" problem and until you track it down it's gonna haunt you no matter what you try.
Isn't it about time (looks over his shoulder for lightening bolt of blasphemy) that you get an auto electrician to sort your faults.
With all the parts you have bought and replaced the costs of taking it to an electrical expert must be almost bearable by now.
I know it hurts the old ego (jezz I bang my head against the wall rather than get anyone else to touch my bike) but you are soooo not enjoying your bike right now and if a trip to the auto electrician can fix that perhaps you should indulge.
You can always learn from the experience, Hell I wanna know what's wrong with your bike, it's identical to mine!!!
 

[kslrr]

Hush is right. Honda made these things to last. The overheating of the Spark Units is a symptom of another issue.  Overheating implies over current.  Find out how to properly check the rest of the system (ie. coils, spaek triggers, wiring) before assuming.

edit: I found another old,short thread on the subject when I was searching the net.

http://forums.sohc4.net/index.php?topic=21223.0

Edit #2:  Ok, it is called TPI ignition. Transistorized Pointless Ignition. JUST LIKE HONDAMANS BOX!
Read this:
http://www.motorcycleproject.com/motorcycle/text/trilogy02.html

[speedy gonzalais]

Ok might have found the problem, my own doing the battery/s are not powerfull enough and being overcharged causing the electrical system to fail in some way. This is where im confused the book says 12ah the battery ive got says 70ah?
so if the battery is being overcharged to the point it cant take no more juice would that cause an overload in the electrical system some where?

[kslrr]

You have a 70ah battery? Does it fit into the battery box ok?  Ok then, the "capacity" of the battery will not cause the system to over charge.  It might be an issue if the internal resistance is greatly different than what the charging system is designed for.  Verify, by the part number, that you have the correct battery.  The US part number is ES12AA, made by Johnson Controls, marketed by Wallmart.  Johnson makes the best lead/acid batteries in the world.  They are also marketed as Sears Diehard and a few others.

[MJL]

A few thoughts... The amp hour number is maximum output, but the battery does not have max output all the time, just what's needed. If your battery is overcharged that would be the fault of the alternator or regulator.

Another thought is that the coils are bad. If they don't have enough resistance then they can use too much voltage and overheat and possibly burn out the ignition units.

[kslrr]

A few thoughts... The amp hour number is maximum output, but the battery does not have max output all the time, just what's needed. If your battery is overcharged that would be the fault of the alternator or regulator.

Another thought is that the coils are bad. If they don't have enough resistance then they can use too much voltage and overheat and possibly burn out the ignition units.

+1

[CB750F2]

Dids I am going to have another try to help you. In your first post you said that you have 14v going to the battery and then further on you said that the battery is going flat. The fact that the bike starts and runs OK indicates that the spark units are doing their job. I have had no experience with these units except with what I have read on the web in the last couple of days. It seems that these units do run hot and it is important to ensure that they have adequate ventilation.
Please advise exactly where you are measuring the 14v.
The figures 12AH and 70AH are capacity specs. A 12AH battery fully charged in good condition can have a load of 0.6amps for 20hrs before it is completely flat while a 70AH battery can have a load of 3.5amps for 20hrs before it is completly flat. Running the 70AH battery on your system would just take longer to recharge. It won't hurt your system provided the battery has no internal faults.
It is very hard for me to help you being so far away but I will try. If you are getting 14v directly across the battery the battery will not go flat. I suggest that you measure the battery voltage while riding - becareful - and then get abck to me.
Pat

[CB750F2]

One other question. Are you running standard coils? Some coils have low primary resistance and will effect the loading on th espark units. Pat

[troppo]

I will fire a wild shot here........
Check your voltage regulator, if thats faulty it could be supplying too much voltage

[Hush]

Man you guys would sure confuse me?
I'm still a big fan of Hush plan #1.

[kslrr]

Man you guys would sure confuse me?
I'm still a big fan of Hush plan #1.

I think you're biased.

[speedy gonzalais]

Ok im getting 13v at the battery terminals @1500rpm and 14v at the terminals 2500-5000rpm past 5000rpm it drops to 13.8v. Now ive just been to see a mechanic i know he pointed out that the battery im using is dry cell (not good) and it isnt 70ah its 7ah, He did a few tests and said its holding a full charge but this rapidly drops when he done some sort of stress test on it so basicly they aint up to the job, just brought a new lead acid battery 12ah as recomended in the book for the bike its twice the size of the other battery and on charge now, il let you all know what happens.
And the coils are original ones.

[CB750F2]

Ok thats good. For the life of me I couldn't imagine how you were able to fit a battery that big. A battery that is too small or just marginal will struggle when the bike is hot so do what you are doing and fit the correct battery for your bike. Then feedback to this thread. Pat

[speedy gonzalais]

new battery is fitted some new problems have arised . The bike started after a few minutes of turning over, with the choke it dont want to go and it turns over and fires now and again but as soon as i open the throttle it wont fire maybe the carbs are blocked AGAIN. Also i went for a ride it was fine i stopped at the garage filled up started the bike and 5 mins into the ride she started missing and backfiring at the same time i noticed the indicators didnt work niether did the lights, i pulled over turned the engine off then back on and she was fine? Im at the stage now where im thinkin of renewing the whole wiring harness.

[crazypj]

It sounds more like voltage regulator is faulty and/or wiring harness/connectors.
 The units are small and do overheat but in my experience, 'customers'  compounded or caused quite a few problems.
 The cdi units have to pass about 4 amps to/from coils (forget which, haven't looked at CB650 since 1980 and CB750/900 DOHC since 1986~87)
Mounting them on a heat sink may help.
 The other problem may be not switching ignition off or faulty switch, ( I've seen it happen where people fill up a gas station, hit kill switch then switch it back to ON while filling up, part of reason Honda used keyed caps, have to switch off ignition when filling)
 current is flowing through coils and 'boxes' when its switched on, relying on pulses switching off to prevent overheating (if you leave ignition on for 20~30 mins without engine running, the potting compound will show which bits overheated inside, usually they are visible from outside  )
 Just my thoughts,

PJ

[speedy gonzalais]

ive got a key cap even if i didnt i still take the keys out when filling, I always turn my bike off at the ignition i never use the kill switch, Saving that for an emergancy.

[speedy gonzalais]

carbs are clean must def be electrical problem.