Timing solid state ignition on 82 gs850

[Muguerza]

Hello guys, im new to here i just purchased my gs850
I am pretty familiar with working on engines, but i have run into an issue, all the manuals for the gs850 only show ignition timing for points
My gs has a solid state ignition timing, and i cannot find anything on the internet. Mostly im looking for how much advance to run, there is not much adjustment like there is on points, but mostly i need to know, how much advance to run, and how far do the magnetic pickup has to be from the rotor.

Any help would be greatly appreciated!
Thanks in advance

 

[posplayr]

All you do is set the initial timing. Use a timing light. If you look through that hole in the plate you will see an "t" and an "f" appear (iirc). Set timing according to that and I'm sure that is in the manual.

 

[tom203]

The little tab on rotor swings by pickups fairly closely- no adjustment required /offered. You sure this is a 82 model ? , looks like 81 with spinning advance weights behind the pickup plate. Make sure those weights move freely (not rusted, no broken springs, etc ). Your manual probably says about 38 degrees full advance by 4000 rpm.

 

[bwringer]

The '82 GS850GL had the mechanical advance, and the '82 GS850G had the electronic advance. No idea why.


OP didn't specify, but apparently has an '82 GS850GL. Unless it's an '81G titled as an '82 or something like that.

The pickups get very close to the rotor. As long as they're even and not actually touching, you're good.


Mugs, you may want to add the exact model of your bike to your signature, and also add your approximate location to your profile. If you're not in the US, there are some important differences.


What leads you to believe the timing and advance need to be checked? Just curious, or is there a problem?

 

[Muguerza]

The '82 GS850GL had the mechanical advance, and the '82 GS850G had the electronic advance. No idea why.


OP didn't specify, but apparently has an '82 GS850GL. Unless it's an '81G titled as an '82 or something like that.

The pickups get very close to the rotor. As long as they're even and not actually touching, you're good.


Mugs, you may want to add the exact model of your bike to your signature, and also add your approximate location to your profile. If you're not in the US, there are some important differences.


What leads you to believe the timing and advance need to be checked? Just curious, or is there a problem?

I apologize, i am located in the US, and it is an '82 gs850gl.
I originally started seeing if it needed adjustment due to poor high rpm power, it pulls really good at low and mid range rpm but top end it just seems to just die, unfortunately the tach didnt work when i got it, so im unsure of what rpm it does it at.

I originally put 87 octane on it, and it had no top end, i removed the airbox and it ran great. Later i learned it required 90 or more octane, and around here there is only 87 89 93, so i went for 93, then it had no torque, i put the airbox on and now its nice and drivable, but no top end

It has brand new plugs, gapped to .7mm, i cleaned out the carbs, petcock is clean as well, no rust in tank, oil will be replaced soon and filter is clean. All cylinders fire no issues

I was just checking timing to see if that had anything to do with the top end power loss

If inital timing is the only thing needed, what does it need to be set up at for advance on this ignition setup?

 

[tom203]

Most of us run 87 octane no problem. You might have a fuel starvation problem ;petcock not supplying enough at high loading or tank cap holding vacuum and not letting fuel flow fast enough.

 

[Killer2600]

Sounds more like fueling issues although bad advance and weak coils/spark can cause high rpm power issues.

 

[posplayr]

Put the air box on and check the voltage to the coils. If it starts and idles and runs through mid range then not likely carbs. It is more usual for carbs to get fowled from setting and pilot jets get plugged and will not idle. Wide open throttle seems to solve most ills.

If that is your problem, check ignition. Look for a hot spark and full voltage to coils.

 

[tkent02]

Check also for a partially clogged exhaust. This could give exactly the symptoms you have.

 

[bwringer]

The GS850 engine is known for its highly entertaining top-end rush. So something else is bad wrong.

It definitely does not require high octane gas. I don't know who told you that -- it certainly wasn't anyone around here who actually rides a GS850. So you can save a buck or two per fill-up now.

If you can move the advancer by hand (it's a simple spring-loaded widget) that's not your issue. There's no curve -- it just slams out to full advance at around 4,000 rpm.

I don't see the massive corrosion that could lead to a frozen advancer, so I think you're very likely barking up the wrong tree.

And yes, the GS850 runs best with the stock exhaust and airbox in place, stock foam air filter, and airbox sealed so that extra air doesn't get in past the end caps and unfiltered air past the filter frame.


Assuming that the airbox is properly sealed, the airbox contains the rubber snorkel on the back, cam timing is correct and that the carbs haven't been rejetted (all things you'll want to verify, not assume), then yes, an exhaust restriction could cause this.

Other possible issues could include carbs rebuilt with kits (kit parts are junk: replace shonky imitation needles and jets with cleaned original parts). Incorrect float levels can also cause starvation issues -- lots of people don't pay attention and set float levels at the top of the float instead of at the step.

Could also be petcock flow issue or tank issue mentioned, although this usually means the bike seems to run fine at high RPM for a few seconds before falling on its face.

In short, there are multiple overlapping problems that can cause this. Go through the list on Basscliff's site and verify each item. If the bike is new to you, do NOT depend on anything the PO said.

 

[bwringer]

If inital timing is the only thing needed, what does it need to be set up at for advance on this ignition setup?

It's fine where it is. Your problem is elsewhere.

 

[Muguerza]

The GS850 engine is known for its highly entertaining top-end rush. So something else is bad wrong.

It definitely does not require high octane gas. I don't know who told you that -- it certainly wasn't anyone around here who actually rides a GS850. So you can save a buck or two per fill-up now.

If you can move the advancer by hand (it's a simple spring-loaded widget) that's not your issue. There's no curve -- it just slams out to full advance at around 4,000 rpm.

I don't see the massive corrosion that could lead to a frozen advancer, so I think you're very likely barking up the wrong tree.

And yes, the GS850 runs best with the stock exhaust and airbox in place, stock foam air filter, and airbox sealed so that extra air doesn't get in past the end caps and unfiltered air past the filter frame.


Assuming that the airbox is properly sealed, the airbox contains the rubber snorkel on the back, cam timing is correct and that the carbs haven't been rejetted (all things you'll want to verify, not assume), then yes, an exhaust restriction could cause this.

Other possible issues could include carbs rebuilt with kits (kit parts are junk: replace shonky imitation needles and jets with cleaned original parts). Incorrect float levels can also cause starvation issues -- lots of people don't pay attention and set float levels at the top of the float instead of at the step.

Could also be petcock flow issue or tank issue mentioned, although this usually means the bike seems to run fine at high RPM for a few seconds before falling on its face.

In short, there are multiple overlapping problems that can cause this. Go through the list on Basscliff's site and verify each item. If the bike is new to you, do NOT depend on anything the PO said.

This is what happens, i have not messed with the timing, i returned it to where it was at the beginning.

Whenever i use the bike, with the airfilter on, the bike seems to hit almost like a revlimiter, it just stops making power. When i remove the airbox, there is much more power and that "revlimiter" goes higher up instead of activating so soon

The bike will continue to increase rpm as long as i go easy on it. As soon as i go half to wot it just hits that "limiter"

I have been thinking it is running too rich, spark plugs looked very black also, i just put new plugs in, and i have been riding it all day, as itll only bog down under more than half throttle. I have to wait for it to cool down so i can check the plugs once more

 

[posplayr]

Sounds like it is running very rich. Taking the air box off increase sir runs less rich more happiness. Why is it running so rich? Did you work on the carbs?