Timing Question

My bike was running pretty good up until a week ago when it started backfiring/missing. I have been following Guido's Tri-Spark post and have been doing most of what people have suggested to him. At first I thought it was a carb issue but have had them off three times, cleaned set (dual Amals with new needles, needle jets, stay up floats, viton) changed balance tube, exhaust nuts tight, spayed for air leaks etc. so moved on to other things. Compression test 150 per side, valves set, new plugs, battery good 12.87 volts off 14.4 when running, gone through wiring, jumpered ignition to bypass switch, cleaned kill and other switches, checked fuel flow…

Tonight I tired to check the timing, I have a Tri-Spark with CNW single coil conversion. I have no experience with timing anything, but borrowed a light off a friend of my Dad and gave it a go. I know it's hard to see in the video, but the white mark on the stator is 28 BTDC. As the bike revs it appears the timing mark is getting to where it needs to be, however, you can hear the backfiring and see the light go out and take a second to get back into sync. I'm not sure how to read what is going on, is the light is just not working correctly (it looks older that the bike) or is this pointing to my problem?

The Tri-Spark is 3.5 years old. Most of what I've read is of Tri-Sparks just going flat then working after a few minutes, has anyone had one just go haywire?

Any suggestion?

Thanks
Trevor

I would say the Tri-spark is a good suspect, but I would check everything else first including plug wires and plugs. Jim

sounds like your engine is misfiring. [ spark disappears the come back again ] Why. Easy to test with twin coils. I suggest you work out where the problem is by substituting different parts. the plugs are probably ok [ since you described the timing light going out when the misfiring occurs ] Try a new coil. try a new ht lead. examine in the dark, the areas round the high tension circuits to see if spark is escaping to the wrong area. spark jumping to earth via the leads or the coil. If you are using a series timing light that may be a problem. suggest using a timing light that its transmitter wraps round the ht lead. Failing that, take it to a mechanic. Have a good time with this. Its not complicated, but it helps to know how the system works.

Thanks for the replies,

The plugs are new NGS BP7ES and it did the same thing with the old plugs so I think they are good. I did check the plug wires as well, they are the same vintage as the ignition 3.5 years old also from CNW and both were 5100 ohms which I think is correct as they are about a foot long. Will try running in the dark tonight. Is there any other way of testing the Tri-Spark? I might try running power directly to it tonight, failing that I'm running out of ideas.

Kerinorton - The timing light I was using has a clip that wraps around the lead, just don't know how to interpret the results, will try it again tonight as well. No Brit bike mechanics around here, not sure if the local Harley or Honda guys will even look at it, but I guess it doesn't hurt to ask.

Trevor

Maybe try an "Italian tune-up" - take it out on an open road and hammer it through the gears, then pin the throttle till it runs out of gas. That should clean it up!

I'm noticing more and more electronic ignition failures of other brands besides Boyer; perhaps the number of other brand units in the field is starting to catch up with Boyer's head start of being the only unit available for many years. The reality of the delicate life of an electronic component on a vibrating piece of machinery is showing itself for what it is.

(points are looking better all the time)

Anytime you put electronic components in a hot spot like the points cavity of your engine it is going to seriously shorten the life of that part.

The Boyer system or the Pazon sure fire do not have electronic parts in the points cavity -just a coil of wire and magnets [called a VR sensor] . They are not affected by the temperature. IMHO - that is the only design worth considering.

Of course the wiring connections are affected by the vibration unless they are securely tied down. Jim

I will simply offer my experience with Tri-Spark bumps in the road and what I have done to fix my few issues.

I put an extra ground on the engine at initial install because many suggested this.

After some initial good running, I was having intermittent cutout problems. More when the engine was hot and it was hot outside. A friend suggested the killswitch might be the culprit. All ignition current goes through that switch and it's not self cleaning. Jumping the kill switch out of the loop ( did it in the big connector under the tank) fixed the problem. I'm not suggesting you can't fix/clean the switch but I preferred my solution.

Good running ensued for quite a while.

Recently was having cutout problems that were growing more frequent, although the bike never quit. Did not seem temperature related. But I took apart the original ignition switch just yesterday and found the contacts quite dirty. Made all the contacts shiny, cleaned out the other muck and grime and dielectric greased it. I rode it 25 miles today and didn't have a problem.

I did have one unit warrantied early on by the seller but I honestly cannot confirm if it was actually bad, based on my switch cleaning efforts yesterday. I'm going to call and tell him to get his opinion on the situation.

So, I believe my troubles have been power-supply related.

Like Jim says, moving the control box outside of the hot and vibrating engine is a positive for anything electronic in the long term.

Easy to spot engine misfiring with a timing light. Aim the light at your eye (it won't hurt you). You'll be able to see a misfire quite readily.

Thanks Whitworth, all good suggestions. I did clean both my switches this week and also cleaned then jumpered the ignition switch to eliminate that. I think the next thing I'll try is running a power right from the battery to the coil. If nothing else the old girl got a lot of preventative maintenance this week.

BrianK said:

Aim the light at your eye (it won't hurt you).

Click to expand...

I nearly died laughing.
Your right, it won't hurt but it's still funny. :lol:

I have a MKIII, and 20 years ago I installed a Boyer ign unit. It never gave me any problems. The machine developed inconsistent idle issues whitch I chalked up to worn Amal carbs and a few years ago had them sleeved and that did improve the idle somewhat but at times the engine would slow and die. It was a easy starter so I just lived with it as I didn't sit around in traffic where it needed a good idle..

Move forward a few years, I had a knee operation and couldn't kick the engine over fast enough to start it. So I reinstalled the electric starter the OE coils, resister and ign points. The Boyer ignition and the starter are not happy together.
Suprise, suprise it starts and runs well and the idle is stable at about 800 rpm.

There is a question coming. Since you set the timing with the Boyer at full advance, is there a set minimum advance like 10deg BTDC at idle like there is with the OE points ign? I'm courious if the Boyer continues to retard the the ignition curve as the engine slows to the point there is not enough advance to keep the engine running at low rpm.

I may be all wet in my thoughts here but with the standard Lucas ignition setup the machine starts, runs and idles very well. Any thoughts??

The old trick was a BSA Auto Advance unit , 15 / 30 degrees . Set at 31 fully advanced in a crankey 750 is thus 1 deg. BTDC at idle .
Would sit at 500 rpm indefinately ( usually - winter wouldve been better to set it higher ) Could make & drink a coffe while it sat there .
And Did . Mk IIs not Concentric Mk 1s .

seeing you asked . Tho with contact breaker assy installed rather than transistorisded .

motoracer8 said:

I have a MKIII, and 20 years ago I installed a Boyer ign unit. It never gave me any problems. The machine developed inconsistent idle issues whitch I chalked up to worn Amal carbs and a few years ago had them sleeved and that did improve the idle somewhat but at times the engine would slow and die. It was a easy starter so I just lived with it as I didn't sit around in traffic where it needed a good idle..

Move forward a few years, I had a knee operation and couldn't kick the engine over fast enough to start it. So I reinstalled the electric starter the OE coils, resister and ign points. The Boyer ignition and the starter are not happy together.
Suprise, suprise it starts and runs well and the idle is stable at about 800 rpm.

There is a question coming. Since you set the timing with the Boyer at full advance, is there a set minimum advance like 10deg BTDC at idle like there is with the OE points ign? I'm courious if the Boyer continues to retard the the ignition curve as the engine slows to the point there is not enough advance to keep the engine running at low rpm.

I may be all wet in my thoughts here but with the standard Lucas ignition setup the machine starts, runs and idles very well. Any thoughts??

Click to expand...

The old style analogue Boyer does not have an advance curve that is consistent enough between units to be able to specify a setting at idle speed. That is why they give a full advance setting only.
Once you have installed and timed the unit at full advance then you can check the timing at idle and use this figure the next time you need to check it. Just make sure it is at the same idle RPM. Jim

Thanks Jim. I had the same issue with a Boyer I installed on a friends BMW, poor idle quality. I never bothered to check advance at idle but my thoughts are the same that it didn't have enough advance at idle.

He tired of the poor idle quality and I reinstalled the points ign and the idle was consistent. That machine is still running at 100,000 miles with ign points.

I removed the Boyer on my Norton when I reinstalled the electric starter. The Boyer would advance when using the electric starter because of the voltage drop and cause kick back. At the time I didn't care because the electric leg was marginal anyway. Now with my knee issues the starter is pretty nice.

Maybe it's time to install alittle more up to date electronic ignition that doesn't have the issues the old Boyer did.

Any suggestions?

Ken

motoracer8 said:

Any suggestions?

Ken

Click to expand...

The new Boyer is not supposed to have the voltage problem that the old Boyer had. The reports I have heard were good.

If you were to buy the new Boyer kit then you could use the present pickup and just change the box. Then you would have a spare pickup.

I have used the Boyer digital with good results however the Boyer digital "power" ignition came with a poor quality coil that failed repeatedly. That was several years ago and things may have changed since. Jim

Jim, in your opinion and experience, which is the best of the Pazon kits on offer?

And, what's happened to your own EI project Jim?

Fast Eddie said:

Jim, in your opinion and experience, which is the best of the Pazon kits on offer?

And, what's happened to your own EI project Jim?

Click to expand...

I have a few EI sets built and sold. I will be doing a video of one on a racebike motor on the dyno next week.

I have parts to build and program one to order but I do not have anything to fit the MK3 850 as of yet. Jim

Whitworth Ranch said:

I will simply offer my experience with Tri-Spark bumps in the road and what I have done to fix my few issues.

I put an extra ground on the engine at initial install because many suggested this.

After some initial good running, I was having intermittent cutout problems. More when the engine was hot and it was hot outside. A friend suggested the killswitch might be the culprit. All ignition current goes through that switch and it's not self cleaning. Jumping the kill switch out of the loop ( did it in the big connector under the tank) fixed the problem. I'm not suggesting you can't fix/clean the switch but I preferred my solution.

Good running ensued for quite a while.

Recently was having cutout problems that were growing more frequent, although the bike never quit. Did not seem temperature related. But I took apart the original ignition switch just yesterday and found the contacts quite dirty. Made all the contacts shiny, cleaned out the other muck and grime and dielectric greased it. I rode it 25 miles today and didn't have a problem.

I did have one unit warrantied early on by the seller but I honestly cannot confirm if it was actually bad, based on my switch cleaning efforts yesterday. I'm going to call and tell him to get his opinion on the situation.

So, I believe my troubles have been power-supply related.

Like Jim says, moving the control box outside of the hot and vibrating engine is a positive for anything electronic in the long term.

Click to expand...

I had 50 miles of running with no hiccups but was cruising at steady throttle today and it skipped a beat one time in a way that is not confidence-inspiring. I've never run power directly to ignition but maybe it is time to do so.
I have to admit the cleaning of the ignition switched improved the missing by quite a bit, but I don't have anything conclusive to offer!

Fast Eddie said:

Jim, in your opinion and experience, which is the best of the Pazon kits on offer?

And, what's happened to your own EI project Jim?

Click to expand...

I guess I forgot the first question. My favorite Pazon for street use is the sure fire.
The smart fire can have a better advance curve but then your back to electronics in the points chest which I don't like for longevity. Jim

Might look into the kill button path too. No risk , just sure full voltage best way to power any of the ignitions is by direct connections to battery then jerk off a lead to shut off. Fuse to ign. will just lower voltage a bit and is no protection to the ign. just the wires to and from.