83gs750e dies at 3500rpm every gear

[TheCafeKid]

The only thing that was replaced on the petcock is the diaphragm that limits the gas...the previous one had giant holes in it and was passing gas through to the vacuum line.

So we replaced it. The gas is flowing beautifully on Prime, On, and Reserve. I tested all there settings to make sure it was getting good flow through going on. So it has seemed to work fine since our replacement.

And like I said the problem existed before the part was replaced.

Ahh ok, missed that part. Ok so, you have no airbox. Do you have pod filters? And if so, did you install a jet kit?

 

[blowerbike]

GS vaccum carbs shut off around 4k when the air box is removed and the carbs are not rejetted/jet kitted.
they will free rev but bog badly when under a load.

 

[rABIDwOLF]

Ahh ok, missed that part. Ok so, you have no airbox. Do you have pod filters? And if so, did you install a jet kit?

He bought the bike from a mechanic guy about 4-5 years ago and the guy had rejetted the whole thing and it ran pretty good.

I'm not sure the exact size of the jets in there its been awhile since I looked I know they are not stock however.

The issue didn't crop up until the end of last season so he got a good 3+ years out of it and a good amount of miles before this popped up out of the blue.

 

[TheCafeKid]

He bought the bike from a mechanic guy about 4-5 years ago and the guy had rejetted the whole thing and it ran pretty good.

I'm not sure the exact size of the jets in there its been awhile since I looked I know they are not stock however.

The issue didn't crop up until the end of last season so he got a good 3+ years out of it and a good amount of miles before this popped up out of the blue.

Hrmm If its jetted, and ran well and now all of the sudden it doesnt, I'd start looking at your electronic advance like was suggested in the first place. Im no expert by any means, but I just cant think of what else would cause the bike to fall on its face like that if everything else was running fine before..

 

[blowerbike]

stop by and i'll plug a known good ignitor box in and see if that fixes it
i'm waiting

 

[rABIDwOLF]

Hrmm If its jetted, and ran well and now all of the sudden it doesnt, I'd start looking at your electronic advance like was suggested in the first place. Im no expert by any means, but I just cant think of what else would cause the bike to fall on its face like that if everything else was running fine before..

That's what had me massively confused. Ran good then one day just started having issues.

Figured it was just dirty carbs (that's the usual suspect) and when that wasn't it got really confused.

Then the whole it working fine in neutral but having issues under load just confused me more.

I've never worked on one with an electronic advance so once we get our hands on a timing light it sounds like we should be able to tell easily if thats the issue.

If that is the issue do we just replace the whole igniter unit or is there something we can tweak?

Also I could really use some tips on how to use a timing light, never used one before and advice would be appreciated.

 

[TheCafeKid]

stop by and i'll plug a known good ignitor box in and see if that fixes it
i'm waiting

Well if his ignitor was bad, would it run at all? I had always read that the ignitors were pretty much a work dont work proposition??

 

[rABIDwOLF]

stop by and i'll plug a known good ignitor box in and see if that fixes it
i'm waiting

HA! I wish I was a little closer and I would do just that

 

[TheCafeKid]

That's what had me massively confused. Ran good then one day just started having issues.

Figured it was just dirty carbs (that's the usual suspect) and when that wasn't it got really confused.

Then the whole it working fine in neutral but having issues under load just confused me more.

I've never worked on one with an electronic advance so once we get our hands on a timing light it sounds like we should be able to tell easily if thats the issue.

If that is the issue do we just replace the whole igniter unit or is there something we can tweak?

Also I could really use some tips on how to use a timing light, never used one before and advice would be appreciated.

And you're ABSOLUTELY SURE you put the carbs back together EXACTLY the way they came apart. I am not trying to insult your intelligence, just making sure. One small mistake like the needle clip being in the wrong slot could cause a major difference like this..

 

[blowerbike]

oooooops..lol

 

[rABIDwOLF]

And you're ABSOLUTELY SURE you put the carbs back together EXACTLY the way they came apart. I am not trying to insult your intelligence, just making sure. One small mistake like the needle clip being in the wrong slot could cause a major difference like this..

yup labeled them and kept everything in separate containers and the whole nine yards...I made that mistake the very first time I ever took carbs apart on another bike and well....lets just say I wasted alot of time getting them back together again ever since then I'm a little over kill on documenting how things come apart

 

[TheCafeKid]

yup labeled them and kept everything in separate containers and the whole nine yards...I made that mistake the very first time I ever took carbs apart on another bike and well....lets just say I wasted alot of time getting them back together again ever since then I'm a little over kill on documenting how things come apart

OK OK... well, The only thing *I* can think is agreeing with everyone else.. either your ignitor is bad, or your electronic advance isnt working (and that may also mean your ignitor is bad..ive never messed with the electronic advance so..) IF your ignitor is bad, you can replace it (Blowerbike has some for sale ) but I'd test it and your advance first. You have a service manual for that bike?? It will show you how to test them..

 

[rABIDwOLF]

You have a service manual for that bike?? It will show you how to test them..

Yeah we have the PDF version of it from BassCliff's website.

It didn't say anything about the electronic advance but it did have the tests to do using a multimeter on the igniter so we'll give that a shot and we'll go grab a timing gun and see if we can figure anything out between the two.

 

[rABIDwOLF]

IF your ignitor is bad, you can replace it (Blowerbike has some for sale )

got a link handy?

 

[TheCafeKid]

got a link handy?

LOL he's been posting right long with me here.. Just shoot him a PM if you find yours is bad. he'll hook you up. I know him personally, good guy, good parts, doesnt sell garbage. Spend my fair share of hard earned dollars with him, and he still has a stash of stuff im trying to get my hands on...lol.

 

[blowerbike]

advance is built into the box and IMHO...
even if the advance quit working i doubt that it would make your bike not pull past 3500RPM.
just would make it kinda doggy unless it actually started retarding it drastically then i guess its possible to be causing your problems.

 

[rABIDwOLF]

advance is built into the box and IMHO...
even if the advance quit working i doubt that it would make your bike not pull past 3500RPM.
just would make it kinda doggy unless it actually started retarding it drastically then i guess its possible to be causing your problems.

Next time I'm over there I'll try and push it more and see what happens.
We didn't want to seriously screw anything up so as soon as it started bogging we would drop it back down to be safe.

Its just hard testing it since it only does it in drive and he took the center stand off so we kinda have to go ride it, we can't just prop it up and let her rip

 

[rABIDwOLF]

LOL he's been posting right long with me here.. Just shoot him a PM if you find yours is bad. he'll hook you up. I know him personally, good guy, good parts, doesnt sell garbage. Spend my fair share of hard earned dollars with him, and he still has a stash of stuff im trying to get my hands on...lol.

and this just proves that I'm running on FAR too little sleep today

 

[Billy Ricks]

advance is built into the box and IMHO...
even if the advance quit working i doubt that it would make your bike not pull past 3500RPM.
just would make it kinda doggy unless it actually started retarding it drastically then i guess its possible to be causing your problems.

What I'm thinking is that if the advance isn't working then the mixture would be super rich above 3.5k. When the advance kicks in it has the same effect as leaning out the carbs. Below 3,500 the advance is something like 15 degrees then goes to 35 degrees above 3,500 IIRC. Might just be enough of a problem to kill the engine under load. I have a couple extra igniters that I intend to keep for spares. I could send one for testing as long as I get it back.

 

[Billy Ricks]

Next time I'm over there I'll try and push it more and see what happens.
We didn't want to seriously screw anything up so as soon as it started bogging we would drop it back down to be safe.

Its just hard testing it since it only does it in drive and he took the center stand off so we kinda have to go ride it, we can't just prop it up and let her rip

Even in neutral you'll see the advance jump with a timing light if it's working the way it should.