Topic: CB500/4 K1 backfiring, misfiring at low rpm and dying out when warm

[zipper]

Hi all!

I'm currently having a few issues with the ignition and i'd like to replace the HT Leads from the coils.
Is it possible to do? When i gave a sneak peak at the coils the cables looked like they were moulded in the coil itself..

Is there any way to get them replaced?

Thanks in advance 


Edit: I'm changing the subject from replacing ht leads to the issue i'm having (Bike misfiring and dying out when the engine is warm, see post #4)

[dave500]

they are moulded in and not replaceable,they are a solid wire and never really wear out unless damaged,you can replace them if you want to grind away at the coils,cut them off and resolder and fart around with epoxy etc,be sure the wires spark plug caps are in good condition and measure 5000 ohms when removed from the wires,they unscrew.

[Deltarider]

I'm currently having a few issues with the ignition and i'd like to replace the HT Leads from the coils.

Can you be more precise like on what issues?
The leads like Dave said are moulded in the coils and the coils rarely fail. Sometimes the cables may seem a bit loose but are still in good working order. If your HTleads are too short or deteriorated you might cut them and connect new wires using the NGK J1 cablecoupler. Louis has them for € 8,-.
http://www.louis.de/_100b5ecc20e8a7958bec4efc1bb154053f/index.php?topic=artnr&artnr=10035359
Issues with the ignition like misses are best observed idling in the dark and then check for sparks between cables (or caps) and the head. Some spray a watermist for easier detection.

[zipper]

Thanks! Too bad they're not replaceable.  I'll see if i'll solder them to a new cable or just get the NGK couplers. 

The issue is that I recently replaced the caps with new ones (SD05F and XD05F) and the cables are now a little too short, although they're still fitting. I wonder what the heck PO:s did in the past.

@Deltarider: thanks for the tip about Louis, i didn't know about them before 

[zipper]

I'm currently having a few issues with the ignition and i'd like to replace the HT Leads from the coils.

Can you be more precise like on what issues?

I were about to open a new post for the real issue but here i go:


The bike starts up, idles and works perfectly when the engine is cold.
Troubles begin after 5-10 minutes of riding, almost proportionally to the engine warming up:
It starts backfiring.
After a minute or two of backfiring, it starts misfiring at low rpm. At higher rpm, i would say above 3-4k it accellerates fine on all cylinders. If i let it idle the engine will just die out.

What could this be caused from? (I suspect the guilty here is the ignition/breaker points)

Done so far (quite a lot, i recently bought the bike that has been unused in a garage for over 5 years):
- Carbs cleaned
- Carbs synched (The spark plugs are perfect brown tan, not rich and not lean)
- Spark plug caps replaced
- Condensers replaced with new Daichi ones
- Fuel lines replaced
- Fuel petcock cleaned and filter/bowl replaced
- Points gapped and static timing done. Bike seems to have #$%*ty Daichi that points right now that aren't that easy to set, but new TEC points have already been ordered
- Sprayed the cables that to go the coils with some WD40 and checked that they're actually connected.
- Valve clearances gapped




 

[Deltarider]

Going through your list my guess would be the condensers but since you said you've replaced them...
Do all 4 backfire or 2&3 or 1&4 respectively?
Nevertheless have a look and see - when engine is warm and is misfiring - if there's abnormal arcing at the points. Some minor sparking between the points at idle is normal.
Check and doublecheck you've installed everything rightly. A mistake with those little fiber insulators is easily made. The result may be intermittent grounding and you can be searching for hours.

and the cables are now a little too short, although they're still fitting. I wonder what the heck PO:s did in the past

.
The PO may have shortened them a bit. Many do when the end of the cablewiring towards the plug becomes a bit loose. If it's done several times cables will become to short.
Louis is very well known. They offer excellent service and they've been elected Best mailorder company in Germany several times. My personal experiences with them are also very good.

[dave500]

the factory wires last forever unless they get physically damaged or soaked in sea water for ten years.

[zipper]

Going through your list my guess would be the condensers but since you said you've replaced them...
Do all 4 backfire or 2&3 or 1&4 respectively?

Now i feel a little stupid for not checking, but i'm not sure. When that happens i just concentrate on quickly getting home before the bike dies out and leaves me on the road.. 

Check and doublecheck you've installed everything rightly. A mistake with those little fiber insulators is easily made. The result may be intermittent grounding and you can be searching for hours.

Again i feel a little stupid... which fiber insulators are you talking about? As it is right now i just reinstalled everything like it were before. If i remember correctly it were something  like this:

| = steel spacer
Bolt | Coil cable | | Condensator cable | (Plastic spacer) ...

[Deltarider]

There are several fiber rings in a set of points. Especially the very small one in the middle can have moved out of its hole. They all should be in he right place. Study a known good set and the pic in the manual.

[Sprocket75]

The NGK splicers work great! I ordered them off of "Shamazon" for $7 each. Stopped by my local auto parts store and picked up some Accel 7mm copper core wires and some new NGK 5K boots. The whole install took less than an hour.

[zipper]

Thanks! I'm still a little confused, where are those fiber rings? Are they somewhere in the red square? (see pic)

Ps: i had almost forgot i had a parts list

[Deltarider]

Yep, they are on the points, on both sides where the little bolt is and in the middle is the tiny ring. But ofcourse you can check the working of the condensers by looking if they arc. 

[zipper]

I finally checked it and it looks like there's arcing(sparks) on the points for cylinders 2/3, while the one for 1/4 doesn't. What's this caused of? Bad condensors? How can i check if they're bad?

I checked the wiring and the plastic paddings on the points and they seem to be connected correctly and tightened well.

[Deltarider]

Easy, you can swap the condensors (they are identical) and see if the problem follows. There is a chance the U-formed connector of the condensors touches ground or the chrome ignitioncover intermittently. Check also if the bulletconnectors somewhere halfway the plate and the coils still connect well.

[zipper]

Thanks a lot Deltarider for the tips! Just to doublecheck, are the points supposed to be arcing when working correctly?

[TwoTired]

Just to doublecheck, are the points supposed to be arcing when working correctly?

That is normal.  It is the nature of how this system works.

[Deltarider]

Yes, some minor sparking is normal. Excessive arcing indicates a faulty condensor. Do you know how to use a multimeter? Check if points 1/4 get current. When opened you should have around 11 Volts. If they get current and at idle don't spark at all, clean contactsurface of the points. I suppose you have set the timing of the ignition well?

[zipper]

About the arcing, when is the sparking too much?

Status :
Worked a little on it today.
I reconnected the condensers according to the parts list, double-checked the plastic paddings, cleaned the points and regapped them.
Now it runs almost okay... At least it doesn't stop on the road.

After the engine warms up it starts misfiring at low rpm while accelerating, not as bad as before, but the symptoms are still there. Backfiring is although gone. Idle is fine and no noticeable misfiring (at idle) is present.

What' next:
I suspect the timing might got off when I regapped the points and need to be re-set, I will try with a static timing tomorrow (and get to check the voltage to the points as suggested by Deltarider at the same time). Too bad I didn't get my TEC points yet because these Daichi are really a pain in the ass to set...

(I also checked the color of the plugs again and they have all the right tan-brown color)

Does it sound like I’m on the right track? Could the misfiring at low rpm be caused from an incorrect ignition?

[Deltarider]

Yep. Timing is crucial. I don't know if you're familiar with it. Have you done it before on other motors?
O.K. You start by setting the gap (0,3 - 0,4 mm). In an ideal world the PO hasn't touched the three screws of the timing plate ever and so you would be able to set the timing by simply gapping the contactbreakers. Alas! Lots of people have played with the plate.
So standard procedure (static) is:
1. Check/Set gap points 1+4 when they have reached maximum opening. Gap should be between 0,3 and 0,4 mm using a feeler gauge.
2. After that you can check the timing 1+4 using a little bulb or a multimeter. Points should start to open at F mark (do you know which one is the F mark? Sure?) If timing is not right, adjustment can be made by rotating the baseplate.
3. When timing 1+4 is satisfactory you can move to 2+3.
4. Check/set gap points 2+3 like you did with 1+4.
5. Then check timing 2+3. If timing is not right, adjustment can be made by moving the little 2+3 plate.
Important to know is that changing the pointsgap will change the timing! So you have to work in the right order. It's not that difficult but it is one of the things you must know how to do.
If you know somebody with a stroboscopic timinglight, ask if you can use it. You will be able to check if advancer works correctly.

Since your bike has been standing for years, here are some other things you want to check
Make sure gaz is not too old and does not contain water. These bikes are very sensitive for water in the carbs.
The O-rings between the carb manifold and the enginehead can leak when they're old. You can detect this by spraying brakecleaner, startpilot or WD-40 around it whilst idling and then monitor eventual changes in rpm. BTW, these O-rings are the same size as the seals under the valvecaps.

[zipper]

Thanks! Unfortunately some PO had previously messed with them as i could tell from the screws and the hateful Daichi points. I'm not that familiar with this type of ignition from earlier but i'm a good and quick learner. :-)

The F-mark is the first mark after the T F, right? And the one after F is the T-mark, which i shall ignore.
I tried re-setting it last evening but it went badly, bike runs even worse than before.  Perhaps the feeler gauge left some residue after itself, even if i were careful to clean it prior using. How sensible are the points?

Does it make any difference if i adjust the timing with the engine cold or hot?

I will try to readjust it tomorrow again following exactly your procedure and set the gaps using a dwell meter, that way i don't risk leaving crap on the points  . I've ordered a strobo timing light but i unfortunately didn't receive it yet. But i bet checking for voltage using a voltmeter is a good start

Gas has been replaced and the manifold to the head seem to be alright, but i will doublecheck with WD40 to be on the safe side. 

[neilc]

were did you order your new points from?and how much

[Deltarider]

Does it make any difference if i adjust the timing with the engine cold or hot?

No, it doesn't.
Below you see your type of advancer with the marks. The red one indicates Top Dead Centre. It is used for checking/setting the valve gaps. Anyway, that red mark is not important for us now.
The next one, just to the right of the red one, is the mark for timing the ignition (static). I've marked it yellow. That mark is 5^o from the T mark. I should say 5^o BTDC. Further to the right (more or less above the 4) you see two marks (blue) close to one another. When a strobocopic light is used at or above 2500 rpm the flash should light them (when ignition is fully advanced). Right in the middle of those two marks is 25^o advance (or 30^o BTDC). When you have set the points gap correctly 0,3mm-0,4mm (using a feeler gauge) or 49^o - 46^o (when a dwellmeter is used), my advice would be to set the timing the dynamic way with the strobe. Personally, when fully advanced, I like the timing on my motor to be a degree outside the most right of those two (blue) marks. One or two degrees extra advance is no problem and can make your motor 'bite' better, livelier.
As a rule of thumb you should concentrate on the ignition at full advance and accept whatever timing at idle is the result.
The strobe is an effective tool to check if the advancer works correctly. Check it.

[zipper]

were did you order your new points from?and how much

I found a bargain off ebay for 15$ each. Too bad he only had 1 of each otherwise i'd have ordered a pair.

[zipper]

I think i'm starting to see the light at the end of the tunnel now. If my gut is right it seems that all the problems were simply caused by #$%*ty points.

I've replaced them with the TEC ones, adjusted the gap using a dwell meter (both are 48degrees now) and adjusted the timing with a multimeter. The bike starts right away without issues and idling and accelleration at idle seems much more smoother than before. Plus now i even understand what Deltarider meant with fiber paddings, the ones on the Daichi turned out to be plastic paddings.. 

It has been raining like crazy here the last few days and i haven't got to try the bike after i did the adjustment. I'll cross my fingers for better weather so i can try it asap. 

[Deltarider]

Congrats. You did well. Be prepared that these bikes' HTleads and sparkplugcaps are a bit 'sensitive' in the wet, like rain.