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Timing Advance on 78 GS1000E

salty_monk

salty_monk

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I just converted over from points to Dyna S & this is somewhat a carry on from an earlier thread but I figured a new title would generate more interest / comments. :)

I timed the unit statically at full advance as per instructions. The points bikes have T - F & Advance timing marks for both 1-4 & 2-3.

Interestingly once timed perfectly at full Advance the light would come on with the line about 1-2mm to the left of the case mark (so initial advance must be slightly higher by whatever degree this equates too).

Today I took the bike out with no timing cover on it & had a play with some settings. I changed nothing else on the bike. 87 Pump gas but it does have a touch of Seafoam in it (as I had the bike off the road for about 5 weeks & it helps to prevent it going stale).

In the Pics below you can see where I have marked the marks timed as per instructions & described above. Light (hooked up to trigger) just coming on at full advance.

You can also see two other pics where I ran more advance & then the same again.

I noticed slightly more grunt low down with the added advance but I wouldn't say it was enough to really notice had I not been riding back to back & is somewhat subjective as I was doing it by seat of pants.

I didn't hear any pinking running low load, low gear uphill, 5th gear up hill (2500 rpms so full advance was in but engine was under a decent amount of load).

So really just wanted to put this out there & see what comments come back. I suspect if I don't get anything conclusive I will probably run it close to the marks I made, perhaps a touch on the side of more advance.

I know others have played with advance on these bikes - Keith Krause in particular reporting that a bit extra on these models helps....

Per instructions:

d97b4915.jpg


Added Advance:

c49988db.jpg


More Added Advance:

d0daa73c.jpg
 
The 1000S racebike I look after is running about 3 deg more advance than standard - and on the highest octane pump gas available here in NZ - supposedly 98 octane.
This figure was established by the time honoured, advance it till it pings,then back it off method - bearing in mind that it doesn't have to live on the street and we're running NGK 9's.
Cylinder filling and scavenging is better than standard so I'm not surprised it only took a little more advance.
Standard heads with the usual poor pipe fitted will respond to more advance than this as others have found.
 
GregT said:
The 1000S racebike I look after is running about 3 deg more advance than standard - and on the highest octane pump gas available here in NZ - supposedly 98 octane.
This figure was established by the time honoured, advance it till it pings,then back it off method - bearing in mind that it doesn't have to live on the street and we're running NGK 9's.
Cylinder filling and scavenging is better than standard so I'm not surprised it only took a little more advance.
Standard heads with the usual poor pipe fitted will respond to more advance than this as others have found.
Click to expand...

Greg, your findings are similar to what I have experienced with my 850. I've experimented with 91, 95 & 98 octane gas. Because my CR is 10.5-1, I started with 98 which gave slightly better top end performance when extra advance was added. I next tried 95 and felt a slight improvement in the midrange torque at the same advance. When 91 was tried, the improvement in lower and mid range torque was quite noticeable, still without pinking.

I did reduce the advance slightly after settling on the 91 and found more mid range improvement. I guess the lower octane fuel is burning off faster, thus not needing as much advance!! Still running NGK 8's. They got a bit hot at Hampton Downs though.
 
That's my big worry... even without pinking it's still possible that this could run HOT HOT HOT in Nevada this summer.

For me the two advantages I can see would be:

1. More bottom end/midrange
2. Improved MPG.

Strange that nobody else has tried messing with this..... Or maybe they just haven't read the thread as yet.

Dan :)
 
salty_monk said:
That's my big worry... even without pinking it's still possible that this could run HOT HOT HOT in Nevada this summer.

For me the two advantages I can see would be:

1. More bottom end/midrange
2. Improved MPG.

Strange that nobody else has tried messing with this..... Or maybe they just haven't read the thread as yet.

Dan :)
Click to expand...

Dan, mine only ran hot when I was flogging it around a race track. I should have been running NGK 9's then. It still wasn't pinking then though.

In summer here, I usually run a 91/95 mix, or straight 95 when its over 30 deg C.

On a recent trip with plenty of undulations and running to 120 kph, I returned 47 mph.
 
The fuel thing is funny (peculiar) I first saw guys mixing 100 and low octane unleaded back in the day when we had a superbike round here.
Team Loctite UK used about 70/30 mix of organiser suppied 100 avgas and 91 bought from the service station down the road from Manfield.
The manager (Steve Parrish ?) reckoned the OW01's went better on this mix - but knowing what I now know about OW advance curves I'd suspect that it just covered up poor burning.
For a while when our top classes were still carburettored and allowed 100 I'd see the occasional guy mixing fuels - all gone now due to EFI & much closer & more accurate fuel metering.
The GS advance curves are as simple as they can be so using lower octane fuel has the same effect as steepening the advance curve.
My 450 is running fixed ignition - 38deg - starts easily, doesn't ping and wants to rev to the sky - on avgas.But what it would be like on the street on pump gas I don't know.
IMO most holes in pistons come about due to a combination of lean burn and too hot a plug. If Nevada in summer is a worry, go to colder plugs.
 
I've been up there before on the same bike at 110 - 120F (ambient temps) with no probs using an 8 plug & stock setup with points. :)
 
pump 85 will boil water at the same rate as 112

I love hearing how fast Avaition fuel is-- BS!! gasoline airplane engines run at 3700 RPM. it has the slowest burning rate of all gasoline LOL

8 plug in 120 weather can you say detonation? and meltdown. MR scorched blue pipes.. that head gets to 400 degrees or more and the guides and seats might fall out, head warps and oil leaks emit from mysterious places.. why do some guys bikes leak in weird places--and others do not.. hmmm

over 85 degrees I have B10eg or B11eg(extended highway) and wait for it to warm up-- 10 more degrees hotter and I'll pull 5-7 degrees timing out of it and adjust the idle speed. ride on my merry way with E.G.T. under 500 on the pipe surface. my pistons and valves love me - I just know it.

most people run es style there cheapest.. eg evx styles get pricey for hobbysts. I have different spark plugs for the seasons.
 
I presume it's the 8 plug... it's the stock one for the bike in any case (bike is largely stock) :)

Presumably your bike is not stock?
 
Try a 9 Dan. The motor will run cooler plus it will be better in those high temps.
 
So that would be a B9ES?

Does it make starting harder & should I change back in Winter? Wouldn't they foul easier too?

Presumably the 750 is better setup for the hot temps with the oil cooler anyway...

Dan :)
 
salty_monk said:
So that would be a B9ES?

Does it make starting harder & should I change back in Winter? Wouldn't they foul easier too?

Presumably the 750 is better setup for the hot temps with the oil cooler anyway...

Dan :)
Click to expand...
8 is a pretty hot plug. I'd run the 9 all year. If you have warm-up problems in the winter go back to the 8.
 
I love hearing how fast Avaition fuel is-- BS!! gasoline airplane engines run at 3700 RPM. it has the slowest burning rate of all gasoline

That was the point in mixing fuels - the OW01's had a very bad problem getting fuel to burn - two peaks in the advance curve, one round 4500rpm of about 45 deg advance and the second at about 6500 rpm of 48 deg advance. At these rpm there was obviously poor turbulence in the chamber and much reluctance to burn.
When they were forced to use fuel supplied by the organisers - an FIM requirement - and it was slow burning avgas, the problem was made worse - flat spots in the midrange I believe - so adding some local low octane swill speeded up the burn rate and filled in the HP curve.
I didn't know this at the time - there were probably 3 OW01's in NZ - but since then I've done my share of 5 valve Yams and found these problems first hand. For a team on the other side of the world from home it was a very good answer to a difficult problem.
 
Ok will maybe try the 9 plug fir the hotter season.... Any more thoughts on the advance settings?
 
salty_monk said:
Ok will maybe try the 9 plug fir the hotter season.... Any more thoughts on the advance settings?
Click to expand...

Dan, do you want good mid range torque, or top end HP figures? Excessive advance will prop up the top end, at the expense of the mid range.

If you're running stock CR 8.8 to 9 -1, the 8's will be fine in summer up to mid 30's deg C. From there on run 9's.

Actually, the 8's are colder plugs than most people realise. My 850 misses intermittently on cold mornings for a couple of minutes until the plugs warm up enough. It's not through poor tuning. It's done it under several different states of carb tuning and when the PO owned it as well.
 
Last edited:
Not interested in top end... low & mid range is much more useful to me... :)

I have pretty much decided I will run as per Dyna instructions as there doesn't seem to be a big "seat of the pants" difference.

Looks like this years trip is going to be a bit cooler so I'll stick with the 8's... I've done it on those before & plenty of hot days with them. (Even up to about 43 degrees - 110F)

Dan :)
 
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