Ignition Timing 101?

[BeamieToo]

I'm in the middle of performing scheduled maintenance on my 2001 1150RT. Valves, TB sync all done and OK. I wanted to check my ignition timing with my inductive timing light so I hooked it up and it was showing "S" through the timing hole at 1100 rpm idle speed.

So my questions are: what is the "S" , shouldn't idle timing be at 0 deg. TDC and can anyone give me a level 101 timing gun (or other) proceedure for setting the correct timing? I am experiencing slight spark knock on heavy loading and suspect the timing may be the culprit. High octane gas is used.

 

Thanks,

Kenny

 

[Boffin]

S is the static timing mark, which is correct for idle. The spark advance is controlled by the motronic and will vary by load - rpm vs throttle position.

Static timing is set by the HES position. There is a small amount of variation available at the HES plate.

 

As an alternative, try nipping over to Germany and running hard in 5th/6th gears - preferably on a hilly road - for a tank of fuel, though at European fuel prices it may be cheaper to drop the heads and de-coke it.

 

Andy

 

edit: Static timing is almost never TDC, you need some advance to give time for the flame-front to develop before the piston starts to descend. Timed at TDC, the engine would not burn anywhere near all of the fuel.

 

Andy

[Jerry Duke]

It's my understanding the only way the timing can be properly set is using the factory equipment. There are ways to advance the timing using the Hall sensor, but done improperly could cause serious damage.

[upflying]

With ignition timing controlled by a computer, I would consider the timing on an oilhead non-adjustable.

Slight spark knock (aka pre-ignition or detonation) on heavy load is not cause for concern. My bike does it occasionally, drop down a gear or reduce throttle a bit.

[BeamieToo]

As an alternative, try nipping over to Germany and running hard in 5th/6th gears - preferably on a hilly road - for a tank of fuel, though at European fuel prices it may be cheaper to drop the heads and de-coke it.

 

Andy

 

Just returned from a 6 day Alps tour. Fully packed and believe you me, I ran it hard on the autobahn return trip !

[T__]

With ignition timing controlled by a computer, I would consider the timing on an oilhead non-adjustable.

Slight spark knock (aka pre-ignition or detonation) on heavy load is not cause for concern. My bike does it occasionally, drop down a gear or reduce throttle a bit.

 

 

 

Bob, it is very adjustable even though the computer controls it (the HES plate is slotted).. I have played with the ign timing on the 1150 a fair amount..

You can’t easily change the spark curve but you can play with the initial timing & that carries all the way across the entire RPM range.. If you add +3° at static you have +3° at 2k,, 3k,,4k,,5k,, etc.. About 3-4° is about all you can add by turning the timing plate,, if you want more you have to get the file out..

 

If you want to fool with the computer part you can mess with the AIT sensor resistance a little.. Won’t give you much but you can trick it a little..

 

 

Twisty

 

 

 

[T__]

I'm in the middle of performing scheduled maintenance on my 2001 1150RT. Valves, TB sync all done and OK. I wanted to check my ignition timing with my inductive timing light so I hooked it up and it was showing "S" through the timing hole at 1100 rpm idle speed.

So my questions are: what is the "S" , shouldn't idle timing be at 0 deg. TDC and can anyone give me a level 101 timing gun (or other) proceedure for setting the correct timing? I am experiencing slight spark knock on heavy loading and suspect the timing may be the culprit. High octane gas is used.

 

Thanks,

Kenny

 

Kenny, yes ,no maybe so..

 

On the 1100 (Motronic 2.2) you can easily depend on the timing marks for dynamic ign timing..

 

On the 1150 (Motronic 2.4) you can’t depend on the (s) mark for running dynamic ign timing.. Sometimes it will be there & sometimes it won’t.. The ign timing on the Motronic 2.4 is very dependent on the computer & sensor influence..

 

The spark timing on the 1150 should really be checked on the BMW MoDiTec as that forces a diagnostic mode,, then holds the base timing for checking..

 

If you are on the (s) “spark” at 1100 RPM’s & you didn’t move the timing plate then you are probably good.. When it goes sensor dependent it will move around a lot..

 

 

Twisty

 

[LPR1100RT]

I'm new to the oil heads but in lurking around the net I found this link which sort of describes what Twisty was talking about. http://advwisdom.hogranch.com/Wisdom/Oilhead%20Timing%20The%20Easy%20Way.html

 

 

 

[BeamieToo]

So fella's...

 

Twisty,

Your advise is always a pleasure to read and receive and if I can put what you say into my own words: It will not matter much where the idle timing is at because the MoTronic will adjust anyway to prevailing conditions during operation. Also the only way to verify static setting is truly correct is to plug in at the dealer. Have I got this right?

 

Lou,

The clear description on the site given seems easy enough. But I think this is for an 1100 because the 1150 has a switch to keep the headlight off. I now wonder if this method also applies to the 1150 engine? Also according to the writer being at S would say that my present timing is at 5 deg. advance. Wouldn't that be too far?

 

Kenny

[LPR1100RT]

Kenny, I'm not 100 percent sure but in the US models there is no way to turn off the headlamp. Laws require a headlamp on at all times while driving so the manufacturers eliminated on/off switches from the bike. My RT HAS an on/off switch which surprised me when I got it. PO informed me it was a Europe Spec model that was bought over seas while in the military then shipped to the US. As far as the "S" timing thing goes I have not even checked it on my bike and I think Twisty or some of the other long timers here would give a much better answer than I.

[crnagel]

 

 

Here are some repair videos for your viewing. They are for the 1200C but I use them for the 1100rt as well.

 

good luck.. I hope will help.

 

 

https://www.bmwmc.net/uploads/tm11/R4V%20EngSvc115_medium.wmv

 

https://www.bmwmc.net/uploads/tm11/R4V%20Ignition%20timing_medium.wmv

 

https://www.bmwmc.net/uploads/tm11/R4V%20Throttle%20Synch_medium.wmv

 

https://www.bmwmc.net/uploads/tm11/Poly%20V-belt%20sequence_medium.wmv