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General Category >> Rubber Side Down! >> Ignition timing advance - Intermittent function
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Message started by Forest on 08/31/26 at 06:49:12

Title: Ignition timing advance - Intermittent function
Post by Forest on 08/31/26 at 06:49:12

Hello all

I'm having some issues with my ride. Or rather; I've BEEN having issues for a few years now. It is running, but I often experience poor performance. Hanging idle, low power or power cutting in and out, knocking or pinging (I'm not sure what the difference is).

I've mainly blamed the carburetor, and it's been taken apart completely a couple of times. I've also replaced the camshaft and rockers because they looked worn, and someone told me it MIGHT be reason. I've had no luck finding the reason for this issue, until a few days ago, when I tried checking the dynamic ignition timing with a strobe light.

At idle the timing mark is at 3 o'clock. It may be advanced a few degrees before TDC, but that's difficult to see on this bike. when I touch the throttle the timing mark jumps to what I perceive as 30° BTDC. This is measured with my eyes only, but I would think, that it was fully advanced. I increase the rpm and the timing mark stays at 30°. As I release the throttle, the mark remains at full advance for a few moments, then shifts between no advance and full advance several times and finaly settles at no advance. This looks very odd to me, and a minute later it stops behaving this way and I see the timing mark move smoothly clockwise with the rpm.

I believe/hope I've found the cause for the poor performance. I would like to replace the TCI module. At the same time I'm also tired of spending money without getting any results. Do any of you have experience with these kinds of issues? The engine runs, only the ignition timing seems to suffer. My theory now is that it stems from the inside of the black box. What do you think?

By the way.. It a Suzuki Savage. Did I mention that?

Title: Re: Ignition timing advance - Intermittent functio
Post by verslagen1 on 08/31/26 at 10:58:51

547D60776166120 wrote:

At idle the timing mark is at 3 o'clock. It may be advanced a few degrees before TDC, but that's difficult to see on this bike. when I touch the throttle the timing mark jumps to what I perceive as 30° BTDC. This is measured with my eyes only, but I would think, that it was fully advanced. I increase the rpm and the timing mark stays at 30°. As I release the throttle, the mark remains at full advance for a few moments, then shifts between no advance and full advance several times and finaly settles at no advance. This looks very odd to me, and a minute later it stops behaving this way and I see the timing mark move smoothly clockwise with the rpm.

w/out doing the same on my bike (which at some point I'll do) timing mark at 3 o'clock should be correct.
but touching the throttle and getting it to jump 30° advance is wrong. timing advance is done electronically, so either bad electronics or bad wiring.
checking the wiring is cheap, and it's my understanding that pushing the starter retards the timing so I would check that 1st.
checking the connector wiring, cleaning the contacts also needs to be done.

Title: Re: Ignition timing advance - Intermittent functio
Post by Forest on 08/31/26 at 11:44:48

I can't help but think it's inside the black box. As far as i can tell, both the pickup and the ignition coil are connected directly to the box. Any timing components would have to be in between those two.

Title: Re: Ignition timing advance - Intermittent functio
Post by Forest on 08/31/26 at 11:49:57

So it turns out, that the black box can be serviced.. maybe. I thought it was potted. Suddenly there are several cheaper options available :)

Since the engine runs as it is supposed to sometimes, I think a bad soldering is more likely than a defective component.

I've cleaned the connector on the box, but I should probably be a little more thorough checking the wiring.

By the way.. I made the mistake of trying to check the timing while the bike was on the side stand. Engine oil went everywhere. Leaning it to the right with the footpeg on a jack reduced the spray to almost nothing. Lesson learned.

Title: Re: Ignition timing advance - Intermittent functio
Post by DragBikeMike on 08/31/26 at 14:11:50

I have observed the transition from idle to 4500 rpm a number of times using a degree wheel and strobe. As I recall, it is a smooth transition, and the timing drops back to original setting when you return to idle. Don't know how you were able to shoot those timing marks with the engine running. I bet that was messy. The tool shown in this old post makes that job a lot easier.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1521968829

Title: Re: Ignition timing advance - Intermittent functio
Post by Forest on 08/31/26 at 15:06:54

Oh wow.. That's an impressive piece of equipment. That would have been neat to have.

For my purpose now, I think the notches in the nut and case will do. I suppose I was lucky to see both normal and erratic behavior moments apart.

My plan now is to first resolder the PCB. It's single sided, so it shouldn't be too bad. Then I'll test it some more.

Thanks for your input both of you.

Title: Re: Ignition timing advance - Intermittent functio
Post by Forest on 09/02/26 at 10:59:22

All right.. So I've re-soldered all of the PCB. One the worst soldering jobs I've done in my long career as an electronics whatever it's called in english.. BUT IT WORKED.

I did the same test as before, and i could not get it to fail (jump to full advance). Now I've just taken her out for a short ride in the sunset, and there was no hanging idle, no dying at red lights and a (pretty) smooth torque from low rpm. So far it's a success, but it was an intermittent problem, so I'm trying to be causiously optimistic :)

Thanks for your help guys and for listening to my woes.