Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: beardylondon on February 21, 2025, 04:47:17 PM
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Hi All
My 550 has sat for many months due to life getting in the way.
We fitted a new coils middle of last year, it ran ok, but was a bit lumpy and spluttered. Put it away for winter and now it wont start.
It is at my Dad's, and I haven't got time to look at for a few weeks. He is only familiar with old British bikes, he has tried all the normal things, but can't get it to start. Battery is good, fuel is good. He thinks perhaps points.
Any tips and tricky greatly appreciated.
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I am not sure, but the modern petrol isn't much good in storage,
What carbs does it have?
Some can be trouble some if not used regularly
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Need more details on what it is like year, model (K of F) etc
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As per my sig, 1976 CB550 K2 (USA import)
Not sure on carbs tbh, I’ll find out and report back
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Did you add any fuel stabiliser?
With the battery fully charged it might be worth a shot of easy start into the air box. If it fires up that might indicate petrol issues/oblocked jets.
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Yes fresh fuel and fuel stabiliser added in October/Novemeber.
Good shout on easy start !
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Kill switch…🫣
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I have experienced many issues in past with E10 petrol due to 10% ethanol content.
One of main problems is the drawing in of water from atmospere and damage to rubber parts not designed to resist
I go out of my way to use Esso E5 Super as was the lowest ethanol %
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I only use Super unleaded, I believe Esso have changed their mix in the last 18 months, apparently it was less than (advertised) 5% ethanol. Not so sure now.
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In addition to other suggestions in trying for response, cover air intake with a rag/towel and crank it in restricted intake "mode" with alternate throttle wide open or closed.
This can encourage :) them to draw through jets that are a little reluctant to get going.
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[...]
It is at my Dad's, [...] He is only familiar with old British bikes, he has tried all the normal things, but can't get it to start. Battery is good, fuel is good. He thinks perhaps points.
So your dad thinks it's ignition related. Let's start there. What was the reason you replaced the coils?
First question is, are the plugcaps connected well? Are plugcaps themselves still OK?
Then to the points. Are points surfaces clean? Do NOT clean them with paper or carton like business cards. I've learned from personal experience that some residu of it can prevent points from contacting.
When you manage to have it run 'lumpy and spluttered', this video may help you diagnose a faulty condenser: https://www.youtube.com/watch?v=t3cuvGVwnjI At the breakerpoints a bit of sparking is normal, excessive sparking or arcing is not good and can indicate a bad condenser. In this vid the left condensor (1+4) is bad, right condensor (2+3) is good.
Video: courtesy Ulf Penner
If you can't get the engine to run, Youtube has tutorials on how to test a condenser aka capacitor. You don't need a Fluke, any cheap DMM will do. https://www.youtube.com/watch?v=gg2emZ91mxI from 01:30 on. I'm suggesting this because you fitted new coils. When people suspect the coils, in many cases the condenser(s) is/are the real culprit.
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If it was running before, then unless anything has changed I would assume it'll start again..but maybe something is blocked.
My Zephyr 550 was running poorly after sitting for a while so I used Valvoline Carburettor Cleaner which, once the engine is hot ( and I used easy-start to get it running because it wasn't starting) is sprayed into the air intakes, the leave the engine running for a bit...and it cleans out the gummed up stuff. On mine I could hear the moment when the carbs suddenly cleared up and it began to run properly. Saved me taking off the carbs and cleaning them out.
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It started up, wasn’t kill switch.
It will tick over and when revved it pops and sputters badly, on idle, without touching the throttle it will randomly increase revs.
The mystery continues…
I will check out above, re: condenser, thank you!
Carb cleaner a good shout too!
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I occasional tip a good measuring of Redex carb cleaner in the tank,
That will get inside the system
Hopefully clear it out
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It's very often some level of restriction within the idle jets and their circuits.
Carb cleaning products worthwhile trying as a simple non invasive way to assess if it'll improve.
The slow/idle modulation does so much on these carburettor, making it look like serious fault is present when in reality it's these.
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Going to check out the condensers.
If they do need replacing, can someone recommend which brand?
I read somewhere, like most stuff these days, the quality of some isn’t great and they fail quickly, but TEC brand is better choice, thoughts?
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I sell the OEM TEC condensers as they are the best.
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Thanks Julie, I'll buy some if I need them!
Another question, Valvoline carburetor cleaner is only available from Opie it seems and is quite expensive when you add delivery.
OB41 has good reviews and is half the price, anyone used it?
https://www.screwfix.com/p/ob41-carburettor-cleaner-400ml/859fe
I sell the OEM TEC condensers as they are the best.
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My TEC condensers are £53 including post for 2 to forum members.
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Cheers
My TEC condensers are £53 including post for 2 to forum members.
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Thanks Julie, I'll buy some if I need them!
Another question, Valvoline carburetor cleaner is only available from Opie it seems and is quite expensive when you add delivery.
OB41 has good reviews and is half the price, anyone used it?
https://www.screwfix.com/p/ob41-carburettor-cleaner-400ml/859fe
I sell the OEM TEC condensers as they are the best.
Those two carb cleaner look quite different in constitution, no experience to offer in comparison and effects that can help.
I do use STP cleaner though, which is much closer to Valvoline in product content, possibly more economic to buy that in general market.
Don't know which stabiliser you've used ? But if you've any spare small amount then some of that administered via syringe into "airscrew" port (remove screw to access) may give direct cleaning of the idle circuit etc. Or the same for carb cleaner via the little tube that comes with them.
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Thanks. Have used Stabil storage fuel stabilizer
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Thanks. Have used Stabil storage fuel stabilizer
Looking at it before in forum thread, it appears to contain plausible chemical concoction to mitigate and dissolve gummy residue. A small amount in concentration of idle circuits may help here.
The Valvoline & STP show content of various % in amongst them, toluene, acetone, naphtha solvent to attempt removal of varnish/gumming etc. Both would be suitable I think.
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Carb cleaner - I used Valvoline because it's instructions ( which I found online somewhere) specifically said it worked without needing to dismantle the carbs (ie) spray it into a running engine .. and as I was getting tired of dismantling carbs I thought it was worth a try.
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[...] But if you've any spare small amount then some of that administered via syringe into "airscrew" port (remove screw to access) may give direct cleaning of the idle circuit etc. [...]
I have had good results with that ^. Spray some carbcleaner from a can with a straw in the orifices. Before removing airscrews, first turn them in fully - GENTLY! - so you can take notes of the position they were sat at and can reposition them again afterwards.
I still don't know what made you replace the coils. Which coils do you have now? Are you sure the primary feed to them is connected firmly? We welcome pics.
I myself haven't used fuel stabilizers so far. When my bike is in hibernation, I leave the carbs in their natural state, which is wet. But... every two months I drain the bowls. Then - with the carbbowls empty - I crank the engine a couple of times, so the downgoing pistons can suck air through the jets. After that I open the petcock to have the bowls refilled again. This has always worked for me. You could 'perfect' this method somewhat: when you drain the bowls, why not remove the drainscrews completely, so you can spray some carbcleaner in there from a can with a straw, refit the drainscrews and then crank the engine a couple of times. Won't hurt and maybe it helps to have the jets getting sucked clean.
If you have the engine running and you suspect one (or more) idle circuits, here's a method for diagnosis.
Turn the airscrew of carb #1 fully in and wait some 30 seconds and then open the airscrew 3 turns out and wait another 30 seconds. If you notice within that minute some change in rpm - this does not have to be much! - the idle circuit still works. Repostion that airscrew to where it was before. Then repeat this for carb #2, then carb #3 and finally carb #4. The difference in rpm is often not much, but... if there's no difference at all, it indicates the idle of that particular carb is disfunctional and needs to be inspected. When all 4 carbs show a change in rpm, there's a good chance all idle circuits are OK. When in doubt, add a liberal amount of a socalled fuel system cleaner additive to the tank and go for a ride. There's no risk of an overdose. These additives are also hydrocarbons and will happily combust.
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I replaced the coils as they were the original ones and 48 years old and one of the cables was damaged, and likely not making a good connection, it was running on 2 at one point
With advice from Ash on here, I bought the nearest you can get and they work fine.
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I replaced the coils as they were the original ones and 48 years old and one of the cables was damaged, and likely not making a good connection, it was running on 2 at one point
With advice from Ash on here, I bought the nearest you can get and they work fine.
For the benefit of forum members what brand of coils did Ash recommend?
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It not the condensers as I have electronic ignition, I didn't know that!
I guess this could have failed?
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Actually it was you Ted which recommended Hendler coils, see this older thread:
https://www.sohc.co.uk/index.php/topic,28601.60.html
I replaced the coils as they were the original ones and 48 years old and one of the cables was damaged, and likely not making a good connection, it was running on 2 at one point
With advice from Ash on here, I bought the nearest you can get and they work fine.
For the benefit of forum members what brand of coils did Ash recommend?
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If it's sat for months it will be the carbs or the fuel has gone off.
As already suggested, clean the carbs, make sure all the jets are clear, fresh fuel and then try again.
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As far as that electronic ignition, I've seen it in the market under different names. Can't remember if this is the one that you had to be aware of an impeded advancer due to bolts that protruded too far at the back side of the plate or the rotor. It woudn't hurt to check the advancer works freely with a strobe timing light.
What I do know is, that on ordering this EI, you had to specify whether the unit was to be used in combination with standard or 3 Ohm coils. For the latter they had a different rotor in their program to limit the dwell somewhat.
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It not the condensers as I have electronic ignition, I didn't know that!
I guess this could have failed?
That looks like a pretty new electronic ignition unit, it's the same brand that DS sells Longfong Kukusan if I am reading it correctly.
Pretty easy to check for spark, it ought to be big & blue.
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I have this EI on my 550k3 with standard coils. No problem with it bought from DS. When it was fitted and set up it was set with the advancer held on full advance.
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Correct, thats what it says on it, dated 2018
It not the condensers as I have electronic ignition, I didn't know that!
I guess this could have failed?
That looks like a pretty new electronic ignition unit, it's the same brand that DS sells Longfong Kukusan if I am reading it correctly.
Pretty easy to check for spark, it ought to be big & blue.
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My understanding is that the two different versions of the DS unit were to replace the two different points plates & advancer unit. One is for Tec the other for Nippon Denso that has a different sized lobe mount on the advancer.
The DS electronic ignition unit has a fair bit of circuitry on that board. By comparison my Dyna electronic unit has just a pair of sensors with no additional circuit board.
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Indeed Ted, I have the Dyna S on the 750. Quite a difference on the appearance.
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It might be the DS ones use less current due to some sort of circuit wizardry.
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Certainly divides opinions among the stalwarts. I thought it was the way to go set it up and forget! No more fettling. I have points and condensers fitted to my current project works fine too. As long as we break that circuits somehow and keep them coils sending pulses to the old spark plugs at the right time all is well.😁
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Do all the popular electronic ignition systems rely on retaining the original mechanical advance/retard mechanism?
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Do all the popular electronic ignition systems rely on retaining the original mechanical advance/retard mechanism?
No, Boyer operates the advance electronically
No mechanical moving parts
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Thanks John.
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UPDATE:
Found a loose lead on one of the plugs, opps.
Got it started, then sprayed in liberal amounts of Valvoline carb cleaner, as suggested on here, worked a treat.
Now starts on the button from cold, and idles at around 1000rpm....
However, it has now this rattle, which does not go away when you pull the clutch in
https://www.dropbox.com/scl/fi/c0e7arncvp55ek4sse5av/Honda.m4a?rlkey=8f8y8x3wsnan273dzkov0lhdl&e=1&dl=0
Thoughts? Cam chain?
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That really doesn't sound nice. Has the engine been apart?
Very pronounced knocking sound with a metallic element in it.
Try putting the bike in gear, and standing on the rear brake, now slowly let the clutch out until you can feel the engine start to bite on it, does the noise go away at the same time?
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Hey, Ken. Do you suspect the primary drive by any chance?
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Thanks, no it’s not been apart in my ownership.
Hmmmm, will try your suggestion.
That really doesn't sound nice. Has the engine been apart?
Very pronounced knocking sound with a metallic element in it.
Try putting the bike in gear, and standing on the rear brake, now slowly let the clutch out until you can feel the engine start to bite on it, does the noise go away at the same time?
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Yes Phil, it sounds like a very loose primary, loading it up with the clutch will make the noise either go away totally or at least lessen it.
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Thanks again, doesn’t sound like an easy or cheap fix?
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If it is, then it's an engine out job, about £50 or so for the chain and another £30 odd for the damper rubbers. After that might need a few gaskets, oil and such.
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Might be worth dropping the sump for a visual too? That will seal the deal if loading the drive changes the noise being generated.
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I can't see or hear the clip to judge.
But, are you sure it's running on all four cylinder competently ? If its not, then they sound poor, and that will definitely flick the chains around too.
Basic check is to start it, then stop after 30 sec, to now check the exhaust headers with your thumb looking for a cold one. If any are cool/cold you'd need to look at that cylinder again to get all running well.
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Thanks, click this link and press play
https://www.dropbox.com/scl/fi/c0e7arncvp55ek4sse5av/Honda.m4a?rlkey=8f8y8x3wsnan273dzkov0lhdl&e=1&dl=0
I can't see or hear the clip to judge.
But, are you sure it's running on all four cylinder competently ? If its not, then they sound poor, and that will definitely flick the chains around too.
Basic check is to start it, then stop after 30 sec, to now check the exhaust headers with your thumb looking for a cold one. If any are cool/cold you'd need to look at that cylinder again to get all running well.
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That sounds bad, I've been trying to identify if it's a half engine speed sound, Camshaft issues have that marker. I don't know the rotation marker for primary drive noises.
Certainly sounds like the chain is contacting the engine casing.
As Ken had said his test should help identify if it's the primary chain.
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Thanks Ted and all.
As I say the bike is at my Dads, have passed all this on, and I will report back.
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Thanks, click this link and press play
https://www.dropbox.com/scl/fi/c0e7arncvp55ek4sse5av/Honda.m4a?rlkey=8f8y8x3wsnan273dzkov0lhdl&e=1&dl=0
I can't see or hear the clip to judge.
But, are you sure it's running on all four cylinder competently ? If its not, then they sound poor, and that will definitely flick the chains around too.
Basic check is to start it, then stop after 30 sec, to now check the exhaust headers with your thumb looking for a cold one. If any are cool/cold you'd need to look at that cylinder again to get all running well.
Yes, tried that but oddly I get a visual representation of it, in bar graph :) with no obvious option to play. Think I'll need a drum kit along with rhythm (distinctly lacking in my skill set) to replicate the sound ;D
I've not got the app though, so possibly limited at that point to view properly.
Trying for cold cylinder though, will tell you something. If it was OK running before, then unlikely to have worn it's chains while inactive.
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This might help...
(https://i.ibb.co/KxLFW8sc/Screenshot-2025-03-03-at-10-26-38.png) (https://ibb.co/HTxnq9PL)
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For whatever reason I'm not getting that functioning toolbar at base.
Nevertheless, hopefully the tests will turn up something from collect advice so far. Hopefully you'll get a more defined cause and other checks, or solution.
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That's running rough as a badger's.... Sounds like it's only running on 2 or 3 cylinders to me and something is clattering. Most probably a worn chain.
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Because I’m not overly familiar with this, please could someone post an exploded view showing what they mean by primary drive?
Thanks!
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Pic from cmsnl off the primary drive hub and primary chain which goes to crankshaft
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Thank you, which number on the drawing is primary?
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How many miles are on this bike?
It could be shot clutch basket rubbers . That makes a terrible racket especially if the bike is not running well or tuned properly.
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Carbs were stripped and cleaned and bike fully set up by a specialist 2.5 years ago, but not many miles since.
Total mileage approx 20k, but it’s an import, so who knows!
How many miles are on this bike?
It could be shot clutch basket rubbers . That makes a terrible racket especially if the bike is not running well or tuned properly.
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Carbs were stripped and cleaned and bike fully set up by a specialist 2.5 years ago, but not many miles since.
Total mileage approx 20k, but it’s an import, so who knows!
How many miles are on this bike?
It could be shot clutch basket rubbers . That makes a terrible racket especially if the bike is not running well or tuned properly.
Carbs will gum up in one winter without use. 2 and a half years will have caused a lot of problems in the carbs.
Clean the carbs now, the earlier work has been undone through lack of use.
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So it continues, looks like it’s running on 2.
Pipe temperatures as follows, from the left hand side looking down, when sitting on the bike, no.1 @ 154 degrees, no.2 @ 50 degrees, no.3@ 152 degrees and no.4 84 degrees.
Answers on a postcard.
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Seems like the slow running circuit in the 2 cold cylinders are not working
In normal settings, no 1-4,and 2-4 are paired with same coils and c/bs
So it seems to rule out electrics
Does fuel come out of all 4 carbs when the drain screws are removed?
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It sounds like you've mixed up the HT leads. The coil with the blue wire runs 1 and 4, the one with the yellow wire runs 2 and 3. I suspect you've got the left hand coil trying to run 1 and 2 and the right hand 3 and 4. Just get them in the right order and it should at least fire on all 4 cylinders.
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Thanks both, we will check this out.
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Been there, done that on my 400, the engine did pop & bang.
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Just to confirm, that no.1 is on the left, as you sit on the bike and look down?
Is there a wiring diagram someone can post?
It sounds like you've mixed up the HT leads. The coil with the blue wire runs 1 and 4, the one with the yellow wire runs 2 and 3. I suspect you've got the left hand coil trying to run 1 and 2 and the right hand 3 and 4. Just get them in the right order and it should at least fire on all 4 cylinders.
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Just to confirm, that no.1 is on the left, as you sit on the bike and look down?
Is there a wiring diagram someone can post?
It sounds like you've mixed up the HT leads. The coil with the blue wire runs 1 and 4, the one with the yellow wire runs 2 and 3. I suspect you've got the left hand coil trying to run 1 and 2 and the right hand 3 and 4. Just get them in the right order and it should at least fire on all 4 cylinders.
Yes the No1 is left most when sitting on bike.
As that #1 cylinder is showing decent running the coil supplying it also must be OK. The other HT lead, from that same coil, MUST go to the far right cylinder which is #4.
That leaves the other coil Independabt with two HT leads ..... which go to the middle two cylinders, doesn't matter which way round.
That will,be correct to run at that.
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Thought to add, for wiring "diagram " :) looking at the #1:4 points on the ignition plate, note the colour of the wire going out of there into the loom, then go up to the coils, same colour wire is the coil for 1&4 plugs, which are the outer most cylinder locations on the engine.
The other coil, obviously going to the middle two cylinder pair.
It doesn't matter which HT lead from one coil goes were, as long as they are identified as above advice. In other words you can swap 1 with 4 as long as they reach, or 2 with 3 ...... but not otherwise.
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I think this bike has Electronic Ignition reading earlier posts.
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That’s right Ted, electronic ignition.
I think this bike has Electronic Ignition reading earlier posts.
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Coil arrangement still the same though.
One coil supplies two HT and will only spark correctly eg 1&4 as paired, with the other coil for 2&3.
If you've anything other than the above combination on HT then it won't run all the cylinders correctly.
In this case that number one cylinder seems correct, the other HT from that coil MUST go to number four cylinder.
That will just leave the other coil to supply the 2&3 cylinders in the middle of the engine.
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I can't see having electronic ignition being involved, as has been said if it's firing on number 1 cylinder then that coil at the other end of the HT lead should also be supplying number 4 cylinder. I believe on production the coil on the left side of the frame supplied cylinders 1 & 4. The corresponding LT wire would be Blue for the left coil.
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He wouldn't be the first to think the left coil supplies the left cylinders and so on. He also won't be the last. Easy mistake to make until you know otherwise. By the temps it's sounding a lot like that's what's happened.
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I've mixed mine up before - made some incredibly loud bangs!
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I can confirm that the left had side coil is feeding plugs 1 and 4. And the right hand coil is feeding 2 & 3.
However on closer inspection the sparks are ALL yellow in colour, not the normal healthy blue you get. Appears to be weak power from coils?
These are Hendler coils I bought:
https://www.ebay.co.uk/itm/145665457928?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=_roJPpVgT4a&sssrc=4429486&ssuid=wmWanCu3SsS&var=&widget_ver=artemis&media=COPY
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Low battery will do that
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Thanks, will double check
Low battery will do that
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Got to be honest and say I much prefer the standard coils to any others on the market. They seem to last and last and give consistent results. There are loads of spare coils out there, just do the Ash mod on them if the HT leads are suspect. Cheaper and more satisfying to do it that way IMO.
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Just to be 100% sure, what colour wires are feeding the left hand coil and if you look at the points plate (I know you have electronic but the term still applies) what colour wire is coming off the left hand trigger mechanism.
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what colour should it be?
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No set colour as it’s aftermarket, however whatever colour wire comes out of the left sided trigger should also be the same colour wire going to the coil firing 1-4 cylinders.
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I meant what colour on the bike’s loom, as that is that’s I thought you were asking, not the colour on the coils themselves.
No set colour as it’s aftermarket, however whatever colour wire comes out of the left sided trigger should also be the same colour wire going to the coil firing 1-4 cylinders.
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Ok, try this, did the electronic ignition come with its own wires, the ones that run under the clutch cover and connect in the rubber boot next to the upper rear engine hanger. If so what does the left hand trigger wire connect to in that boot, the blue or the yellow?
Then check what colour wires the coil running 1-4 cylinders connect to on the loom, again either blue or yellow. That will tell us if it’s been wired correctly
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No idea, it was installed on the bike when I bought it!
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All you need to do is remove the points cover and look and report.
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I’m not currently by the bike, but if you look at page 2 of this thread, there’s a photo of the electronic ignition.
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I think thats a Dave Silver special
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Yeah that's a Kokusan. Are there just 2 wires coming from it?
If so, try swapping them where they go into the harness near the engine mount. Try the engine and see if it's better or worse. If worse swap back.
The symptoms really sound like a coil problem BUT it could just be a coincidence, maybe it's a carb blockage and it just appears to be coil related. Let's get the coil out of the equation and move on from there.
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If you have the original points plate & advancer might be worth going back to points to for a trial period.
Although I have an (unbranded) electronic ignition unit for my 500 I am still on points at the moment.
To be able to run on 2 cylinders running/working on separate coils, seems unlikely (though not impossible) that both the coils are failing to produce the next required spark.
I don't know enough about how coils work to say that with any confidence. As each coil is producing a wasted spark I would expect a spark generation issue to affect all four cylinders.
I have the Hendler coils on my 500.
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no I don't have original points, I bought it with the electronic ignition.it ran fine when I bought it 4 years ago and even better after I had the carbs cleaned and balanced 2.5 years ago.
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When you fitted the replacement coils what plug caps did you use?
Is there any possibility of a poor HT connection at the caps ?
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Genuine NGK ones, I spent some time weeding out the fake ones and made sure they are genuine.
Further update:
On fully charged battery, the spark on all 4 got a little bit bluer, but the spark was quite small and dancing around.
Also, all 4 plugs look the same, so must be getting the same power etc?