GREAT DIFFICULTY TIMING the BIKE - HELP!

ANLAF

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Fellers

I have never had so much trouble, and some weird stuff going on.

Recent PMA failure led to reg-rec blowing and battery fry-up. So, Fixed it, and I'm on borrowed 3-phase reg-rec until Hugh's replacement gets here.

While all that was going on I tinkered with everything trying to find problem. So when I found it, I went back to square one. Checked cam chain (perfect - nearly new anyway); valve clearances (spot-on - checked and re-checked); timing (Boyer - accurate and all in order; plugs (cleaned and checked gap); in-line filter (cleaned it); wiring (checked everything, twice and more); new HT leads; checked ohms reading on plug caps (within tolerance)

Then put carbs back on - and tried to start. Only fired after many many kicks (what happened to first/second time?). And when it started it was hovering. So, checked all the above again (all in order).

Must be the carbs so took the beauties apart. Pilots 27.5 cleaned and seated correctly; same with mains (135 is a bit high, but worked for me so far); needle on position 2, floats 25mm, good gaskets; then I noticed one needle jet not tight in position - so I took off thos 76/77 BS38s and put on my 78/79 BS38s. I've got through pipes and UNIs so replaced 27.5 pilot with 30, kept main at 135, needle position 2. Mix screw 2.25 as guide; tried floats at 24 as per carb guide - didn't like that, so 25mm and bingo, fired first time.

PROBLEM - the bike does not sound right and is not running right, and I can't get it running back to it's smooth self.

SYMPTOMS - I get it running decent idle while on side stand but when I bring it up the engine stops.

TRIED SO FAR = I tried dead cylinder. Left cylinder co-operated while I tested the mix, but right cylinder just stops when I pull plug cap. Tried dropping pilot to 27.5, but started hovering (jet too small), so back to 30. Tried advancing timing, but starts to hover on the idle when I drop the rpm.

HELP! there is an solution to this problem out there - there is always an solution.

ANLAF
 
Hi, ANLAF. Only have two ideas. First, have you confirmed that the ignition timing marks on the rotor/housing are still correct? Second, try using an independent battery for the ignition...
 
Have you put a light on it to check the timing?

I would also make sure that your timing curve is advancing like it should. Boyer has electronic advance right?
 
Thanks Fellers

1. The timing marks - I'm with you all the way. Must be a couple of dozen times with those plugs out finding TDC and then making sure the Rotor lines up the the mark.

2. I have wired-in my brand new battery - gives off big fat spark.

3. I have a strobe timing light idles at FIRE (what's that, 19 degrees) and increased rpm should send the illuminated line to the ADVANCE mark (38 degrees).

4. Yep, Boyer sorts out the curve.

QUESTION - the PMA fault did fo rthe reg-rec and previous battery, but the coild is still working (part of Boyer set-up) and so is the Boyer electonic box of tricks. Am I missisng something really obvious like a fault in the ignition circuit?

It's firing and sparking - I am tempted to think it is the timing and I have the marks somehow in the wrong place or TDC is not where I think it is.

The dead cylinder method working well on the left cylinder, but stopping when testing the right - and stopping when I lift the bike to vertical.

I swapped around the leads, just in case. Could it be I have the leads to the Boyer the wrong way round? But would it not even start if I hhad?

Great support fellers, much appreciated. I have a bikers weekend and the first wave are there tomorrow at 5pm - I wonder if I can get it fixed...

ANLAF
 
Question for you ANLAF as I am not that familiar with the Boyer ignition, is it a wasted spark system like the TCI or Pamco ignitions?

How exactly are you doing the dead cylinder method, are you pulling a spark plug wire or a cap off the barbs on the intake boots or using an extra spark plug grounded to the engine?

You may some kind of short or intermittent connection that is being affected by the lift to vertical and/or movement of the spark plug wire for the dead cylinder test.

Have you verified spark to both cylinders?
 
Ippy

Looks like wasted spark - both sparking simultaneously as they lie on the engine block.

Dead cylinder method: start-up with two cylinders, have spare plug secure against the blck. When running lift left lug and quickly fix it to the spare... that works. When I try lifting the right cylinder I get the cap on to spare plug but engine cuts out. Can I anticipate you suggesting starting-up on just one cylinder? I will do that tomorrow (night is come here).

I will check specificllly the right HT lead to coil - you may be on to something there. I will check again for loose connections and intermittent shorts.

It has to be something, and I will find it.

Thanks, Ippy.

ANLAF
 
If you have a boyer system the timing is the same on both cylinders, boyers use a twin coil, if you have looked at your carbs I would suggest you look at the rubbers, unless you have a lead or plug/ plug cap gone I doubt it's the ignition.
 
Fellers

I have never had so much trouble, and some weird stuff going on.



Then put carbs back on - and tried to start.And when it started it was hovering.

PROBLEM - the bike does not sound right and is not running right, and I can't get it running back to it's smooth self.

SYMPTOMS - I get it running decent idle while on side stand but when I bring it up the engine stops.

Tried advancing timing, but starts to hover on the idle when I drop the rpm.



ANLAF

By hovering idle do you mean that when you blip the throttle the revs stay high and don't return to idle rpm ?
If so thats a classic sign of weak mixture generally caused by air leak/s around the stub/carb and carb/engine joints. The colour of your spark plugs would confirm this if this was the issue.
Have you tried spraying some WD40 around the stubs when the engine is idleing to check for air leaks ?
 
regarding the Boyer.

If you have the Micro Digital Power Boyer with electronic advance you shouldn't need to use a timing light at all except for fine tuning.

The Boyer should be set up statically .

Turn the engine anti-clockwise until the rotor mark lines up with the first timing mark on the stator.(the one furthest from T TDC )

Set the pvc stator plate so the that the white painted dot lines up with the hole in the pvc stator plate and then tighten the lock nut on the Boyer threaded bar.! thats it..

The boyer unit will now give you the correct amount of advance according to rpm up to maximum advance at 3000rpm.

If you want to check that the advance curve is working then check with a timing light but you shouldn't need to set the Boyer up with it.
PS don't reverse the wires to the Boyer box One is 12v+ the other is 0v ground they need to be the correct way round.

http://www.boyerbransden.com/pdf/KIT00303.pdf
 
I just noticed another error in the Boyer Bransen instructions which makes things a bit confusing.
This is line 5
Remove the spark plugs & alternator cover to reveal the timing marks. Using a 17mm socket spanner
on the alternator bolt turn the engine anticlockwise until the first or front of the three timing marks
lines up with the timing mark on the alternator rotor.
Please note this is the full advance mark. It is not marked with any adjacent letter.
Continuing anticlockwise the next mark is F which is the low speed (full retard) mark & lastly T (top dead centre


This is not a retard mark but the idle advance mark.

If it were a retarded ignition mark it would of course be on the other side of the T TDC mark :doh:
 
...Dead cylinder method: start-up with two cylinders, ... When I try lifting the right cylinder I get the cap on to spare plug but engine cuts out...

That means that the right cylinder is probably fine, it's the one that's pulling the load.
The left cylinder sounds dead, since you get no change when its plug wire is pulled.
Make sense?
 
Fellers

I will be checking the HT leads first thing tomorrow to eliminate ignition as the cause, thanks jay760. I have done the spray to carbs testing (no air leaks) Peanit, and set-up the Boyer absolutely correctly.

YwoMay - yes, makes sense. Oh oh! could this mean I may have damaged something inlet valve-ish finding TDC so many times? Or could it be the carbs are somehow so way out of synch? I bench-synched so they should be fine to start-up then need fine-tuning

OK, the bike sounds ropey, but there is still a big difference when I take a plug off.

O managed to get the to work the dead cylinder method on both cylinders by keeping the rev up, but cut out again (no plug cap on right plug) when I brought the bike to vertical. Hmmm.

ANLAF
 
Anlaf
it would be very helpful if you posted a short video so that we can hear the engine and see the problem first hand so to speak.


If you are happy you have set up the Boyer correctly I'm not sure why you are testing the advance curve with a timing light? If there was anything wrong with your ignition or advance it would effect both cylinders

It sounds like you are testing stuff at random now in deperation.

As twomany says one of your cylinders is not firing correctly .I would start there.

First do a compression test to make certain you do not have a compression leak as you had previously with No1 Banana. Fit the tester then stick the bike in second gear and run alongside the bike so the engine turns over at least 10 times each cylinder .

I would fit the pair of carbs that you know work.

I would just recheck that you set the valves on each cylinder when that cylinder is at top dead centre

You've tested the plugs and leads and caps by swopping then so you can eliminate them.

My guess is it is a poor fuel flow to the lazy cylinder giving a weak mix ,erratic idle and a 'hovering idle' with slow return of revs to normal idle.

Lastly have you tried swopping coils ? how does the spark compare between the two HT leads?
 
Peanut,
Compression 155 both cylinders. Only single (dual) Boyer coil on mine. Called Boyer and Stuart was superb, and spent 30 mins on phone with me taking me through various diagnostic tests. Coil in good shape (0.6 ohms primary and 2.75 ohms secondary). I did the voltage drop test from battery to ignition - all consistent 12.53v.

Started first time, but still some engine surge and some hovering.

ANLAF
 
Peanut,
Compression 155 both cylinders. Only single (dual) Boyer coil on mine. Called Boyer and Stuart was superb, and spent 30 mins on phone with me taking me through various diagnostic tests. Coil in good shape (0.6 ohms primary and 2.75 ohms secondary). I did the voltage drop test from battery to ignition - all consistent 12.53v.

Started first time, but still some engine surge and some hovering.

ANLAF
Thats good news so you know that the boyer is functioning correctly and you can eliminate that.

what do you mean by 'hovering '????:confused:

Do you mean that the idle rpm is higher than it should be ?
Is the rpm fluctuating all the time ???
Is the engine 'huntering'
Does the engine rpm come down to idle quickly when you blip the throttle ? or does it stay high for a while and then come down slowly.

What happens to the idle when the engine reaches temperature ?

WHat colour are the spark plugs ???

We need more information Anlaf or perhaps one of your excellent videos ,adjectives mean one thing to one person and often something different to others.
 
Thanks Peanut

I'll do a video today. Yesterday I noticed the spark is weak and intermittent. Battery charged and in good condition/ I flicked the kill-switch (a toggle) on and off. Boyer makes the spark plugs spark when power is turned on - and it did, but when I repeated this it missed a couple of sparks. When I kick over what used to be a big fat spark on both plugs is now weak and not on every kick. Sounds like I am getting closer to finding the problem - perhaps one of the two switches I have on the bike has corroded inside or is just not working properly.

Engine itself sounds like it is surging and not a smooth continuous rumble in there. Ticks over at temperature, but unhappy with itself with the surging. Hovering high rpm not returning to idle when blipping throttle) was solved by making some adjustments to mix screw, but then engine stalled. Looks like it is all down to the weak intermittent spark. Likely source short, open, or ground. Fingers crossed it is the toggle.

Spark plugs are tan coloured but getting wet (fuel) and backer on one side of the electrode (presume this is fuel not burning with the intermittent spark).
By the way, solved the very mysterious engine cut-out why bringing bike to vertical - that was a simple (but hidden) loose connection.

ANLAF
 
ahh... looks like you are making good progress .:thumbsup:

Reckon you might have it cracked today if the rain holds off.
 
You may want to thoroughly recheck your coil. The method of popping-off a plug cap (while the engine is running) on a single dual-fire coil will likely experience more than a couple of sparks during the rapid transit from the installed plug to the dummy plug....
 
Thanks fellers...

DONE IT!

After all the kerfuffle it was my kill switch that was knackered. Good old multimeter came up trumps. The fault didn't reveal itself so easily. Did everything on the bike, got down to electrics, traced the only possible fault area, by-passed the kill switch, fired first time, runs sweet as a nut off a sweet running XS650 nut tree.

Der fliegende Banane fliegt noch mal wieder.

Now, where's my helmet?

I hope my troubles might help someone else along the way...

ANLAF
 
Congrats ANLAF on some good detective work. Nothing like multiple problems creating a little bit of chaos. Without chaos our lives would be boring.

Ja, wenn die bananna fliegt es ist eine gute Sache.
 
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