My Stick Coil Mod Doesn't work! Any Ideas?

[zimm]

what ignition/cdi is on there ? have you tried a different one ?

[Mori Man]

Send the bike to me, i'll sort it and send back

Joking aside - real pain in the ass chasing gremlins, the list of possibilities is phenominal !

Here's another:

The stick coils you fitted had an inherint fault with them - they have overloaded your electrical system so your CDI / Reg/Rectify are now failing so even swapping back to your coild where you know the problem didn't exist - it does.

Hopefully your next set of carb's does cure it.

Anyone local to you with a good running bike?

Try set up a meeting where you have your bike with standard coils fitted and exchange the Reg/ Rectify and see if it cures it - if not also fit their CDI, still no change it's a whole new gremlin.

If it cures it replace your reg and see if it is still ok - problem comes back bin your reg.

Also try same test with CDI

Buy person a beer or two and offer a kip for for the night

I've currently got my FCR's down to their component parts - thank fook i took oodles of photos dismanling them, there's a freakin lot of parts ! But they are going to run sweet as after the overhaul

Good Luck,

MM!

[Neosophist]

I thought of CDI, REG/REC, Junction box.

Since the stick coil mod didn't work I put the coils back to standard ones.

I've got a full wiring loom with all ancilleries from a good known running bike as part of my 'spares'

I've tried that CDI, Reg/Rec, Junction box with the standard coils to no avail.

It's going to be something daft.

When I originally brought the bike (supposidly low mileage) it had been standing 6 years.

The carbs were a right state.

I've cleaned the carbs a LOT!

Done the valve clearances (timing is fine)

I was still getting lots of rev hanging though but after a while it went away.

Done about 1000 miles on the bike since I got it on the road and decided to do the stick-coil mod as it was a bit of a PITA to start when hot.

Hasn't been running right since around then, although it could have been just before, I can't remember now.

The CDI is the Jap blue one with L sticker on it (both are the same)

Compression tester adapter was shipped today so i'll compression test it fully over the weekend, see if any cylinder has lost compression.

Watching some carbs on ebay (as it's the only thing I dont have at hand) as there the last thing to try.

The carbs on it are standard ZXR carbs, 32mm bore 90 main jets.

Tried pilot screws at 1-5/8, 2.0 and 2.5 all don't make any different to curing the bogging at idle.

Could be something internally wrong with one of the carbs.. I noticed when I got them that one of the float bowl pins had sized solid (water in the carb?)

If new carbs dont' sort it I'm half tempted to send it to the motherland for some TLC from you Mori

Either that or attack it with hammer!

The plugs are a lovely Tan brown colour and the bike runs nice apart from wanting to die when it's idling every few seconds :smt013

Replaced the ZX4 camchain tension with a proper Kawasaki one too but havn't road it anywhere to see if thats made any difference.

[RedexRobB]

I was still getting lots of rev hanging though but after a while it went away.

Now you say that id be tempted to look into that further.

[Neosophist]

Isn't hanging revs usually air leak / pilot related?

It went away after cleaning / reseating the carbs.

It's got new carb rubbers on it now and the revs don't hang, they go cleanly up and come cleanly back down.

I put it down to the carbs being diry / not seated right, unless you think it could have been something else?

[Mori Man]

Here's hoping it is the carb's.

When i first got my bike it had been sitting for 2~3yrs and the carb's were solid with green goo - fuel that's gone off ! It smells foul too !!

So after stripping them down washing them out and cleaning up the jets I got the bike to fire up on a jar of fresh fuel going through them. Even after running for a while no way were they ever going to ever tick over, it was just enough for me to see / hear the engine run.

I then got a set of SP FCR's and have never looked back

I was told that when carb's get that bad a full strip and ultra sonic bath are the only way to ever get them cleaned out with out having problems - the goo blocks passageways your cleaner never gets good access too.

Here's hoping your next set haven't been left neglected with fuel in them too.

MM!

[Neosophist]

Ok I compression tested the bike

All of the cylinders are 110psi +/- 3psi

The usable range in the book is 99 - 156psi so i'm assuming that this is ok?

New carbs next, nothing else left to try!

I was thinking the FCR route, my friend had (maybe still has) some ZXR400 FCR flat slides for sale but there not the SP ones.. i.e. don't have the TPS connector, I dont know how well normal ones would be for the road?

Going to get some cheap standard ones first see if I can resolve this issue, no point shelling out on FCR's if there not going to fix the problem

[buttons12]

Hi had a prob like this on my bike (zxr750) okay if revs were up but at tick over would go lumpy and cut out, was a really bad short took 9 months to sort, checked every thing like you.
Well straight to the prob it was the main fuse on the starter relay had melted not blown. outside of cover looked ok but had to cut and prize off.
Inside the fuse was all melted but still worked but had melted through the inside of cover causing the short may be worth a check.
Think when my alarm packed in started the process.

[Neosophist]

Good call, I hadn't checked that one out.

However, it's made no difference.

I've put a new 30Amp fuse in there and cleaned / WD40'd all the connections.

The problem seems to get worse as it warms up.

But that might just be becuase the engines lumpy when cold anyway *sigh*

[parby81]

okay, joining in with this one again,

I have just done the following mod and also seem to have come up with some problems. Bike runs fine on the original coils (yes MM i have swapped them back). Bike runs fine on stick coils.
The problem seems to be idling. My electric and chargin system is working fine and all my earth points are clean and copper greased up. These stick coils seem to give a better spark but at the same time draw more power in their use. The bike idles ok with the lights off etc. But as you load the electrical system the idle gets worse until with headlights on, indicator on and brake lights on (sort of thing you may do at a set of traffic lights) the bike idles roughly then dies and then is a right butt to start.
Two solutions then I can think of then,
1. get different stick coils (got mine from a breaker and they have different numbers printed on the top, so although the same size and shape, i'm not sure they are all cbr600 ones. Maybe the resistances are slightly off being odd, and this is causing a greater power drain for the spark.
2. turn the revs up slightly so that the generator is producing slightly more power, and therefore the bike shouldn't stall.

Anybody else tried turning all their electrics on whilst sat at idle that have also done the stick coil mod?

[Mori Man]

Honestly sounds like your battery isn't holding the amperage.

As your turning stuff on it's draining the battery and at tickover the generator isn't giving enough juice, how old is the battery ? was it left in the cold over winter ?

Although your rectifier might be giving correct voltage readings maybe it's not supplying the kick.

Easy solution if some one is local to you is do a swap of each item ie. their bike is fine so try their battery out and they try yours - problem swaps to other bike theres your culprit. Same goes for the reg/rec too

As I said some things become aparent when you change stuff not as a direct cause of them doing it but because other weaknesses existed and are brought to light.

Now you have said as you put demand on the system it does sound like battery or generator or reg/rec'

If all things wear/age at same time you could imagine that the item still functions just maybe not to its full peak/potential , when you change something to young, bright and full of pizzaz it makes the other parts show their age. Put a spotty teenager in amongst 70+ year olds and see who sticks out like a sore thumb

It's much the same thing just mechanical.

MM!

[parby81]

yeah i get ya, battery is new though only bought in january and i commute on it pretty much twice a week so its getting charged regularly. Any period of time its left for then i would stick it on my optimate or ctek battery charger, but i can honestly say i haven't been off it for more than a week all year. Thats why i disregarded the fuel bit in your PM, always fill up with Shell and its never in there longer than a fortnight. I will try a different battery though and see what this kicks up.

[Mori Man]

Why I say the battery is I got a new one when I rebuilt in August , over the winter months the bike sat but I removed it and put in my kitchen.

Was using my ZRX as if anything happened with slippy roads no plastic to think about but come some 8 weeks later and battery in - it was fooked !

No amount of charging or changing acid got it back :smt013 Less than 3 months old and fooked !

Put my ZRX battery in and off it went like a rocket, strangely enough it still has the ZRX battery in it and it has the ZXR battery in that

Lame as fook, I know

[parby81]

well, i have just broken my multimeter somehow. But basically, three stick coils have the same numbers and resistance, the other one has no number or even saying denso anywhere and a lower resistance. And this one seems to be leaking an oily substance so i think that is slightly fubar'd. Ah well!
with sticks on battery was at 13.5v at tick over, switch things on and it slowly cam down till fan came on and took it to 12v and die. old coils in and even with everything on it doesnt go lower than 12.3v at idle. Bang on 14.4v at 4000rpm with both stick and old coils. I think its a mixture of things but one broken stick coil doesnt help!!

[Neosophist]

well, i have just broken my multimeter somehow. But basically, three stick coils have the same numbers and resistance, the other one has no number or even saying denso anywhere and a lower resistance. And this one seems to be leaking an oily substance so i think that is slightly fubar'd. Ah well!
with sticks on battery was at 13.5v at tick over, switch things on and it slowly cam down till fan came on and took it to 12v and die. old coils in and even with everything on it doesnt go lower than 12.3v at idle. Bang on 14.4v at 4000rpm with both stick and old coils. I think its a mixture of things but one broken stick coil doesnt help!!

I forgot to reply to this.. my problem was a combination of a intermittent spark-plug and an intermittent stick coil.

They were both on the knife-edge of being fubard so sometimes they would work and sometimes they wouldn't, this really threw me for a while.

I spoke to a few american racers while doing this mod and they reckon you can over-heat them. They originally fire separatly but joining them together makes them fire a wasted spark, they wern't designed for this so can over-heat. Never had it happen but apparantly they have.

Also wiring them up in series halves the voltage to the coils.

You can work out their current draw...

V=IR

I=V/R.

The coils have approx 1.8 ohms each (measure them!) add them up... 3.6 ohms for them wired up correctly in series. (this matches the original coils)

12/3.6 = 3.333amp

Lets get the wattage of that.

Watts Law..

P = VI

39.96 watts each set of coils.

So hats almost 7 amps / 80 watts for all 4 stick coils, providing they are wired up correclty they shouldn't drain anymore juice than the originals.

Running them in series also halves the voltage to the coils, not sure how the original ones are wired internally, but on the bikes the stick coils came from their run at 12 volts.

In light of this I didn't bother with the stick coil mod. Last thing I wanted was the possibility of overheating the coils on a long ride