Struggled after 30 min

[bigbadwolf]

Hey All, So I've got an '83 GS650 that I just got done putting back together. There has been some McGuyvering involved. I couldn't find the airbox that the filter sits in so I had to finagle something. I've upgraded to a modern fuse box and had to rig up a choke. Anyhow. I got it up and running very nicely, dropped down to idle like a champ and revved through the ranges and gears nicely with good power. After riding happily for about a half an hour, it suddenly dropped in power and didn't want to idle with out 1/2 throttle. The tank is freshly coated so it shouldn't have sucked anything from the fuel (which is fresh). Vaccuum lines and all are connected. Any thoughts?

 

[Nessism]

Tank not venting? Did you make sure the gas tank vapor baffle vent is open?

 

[Guest]

Possible fuel flow issue or maybe a dropped coil

 

[BigD_83]

Hey All, So I've got an '83 GS650 that I just got done putting back together. There has been some McGuyvering involved. I couldn't find the airbox that the filter sits in so I had to finagle something. I've upgraded to a modern fuse box and had to rig up a choke. Anyhow. I got it up and running very nicely, dropped down to idle like a champ and revved through the ranges and gears nicely with good power. After riding happily for about a half an hour, it suddenly dropped in power and didn't want to idle with out 1/2 throttle. The tank is freshly coated so it shouldn't have sucked anything from the fuel (which is fresh). Vaccuum lines and all are connected. Any thoughts?

Hey bigbadwolf...

you'll probably want to drop in to this thread:

http://www.thegsresources.com/_forum/showthread.php?t=179526

Jasper is having a similar problem to yours. So far there are no solutions, but you can see where the advice is coming from and where you are likely heading.

 

[sachsaca]

Good luck. I read alot of these posts to try and gain knowlege from these guys. I will add my two cents worth. Remember the kiss principle, keep it simple stupid. Start with the easy stuff and go from there. I had a fuel problem, found out my tank was just low on gas while I was putting everything back together, going to reserve fixed that, KISS. Start with the basic stuff and climb out from there. Good luck, sometimes you get lucky and it is the easy stuff...

 

[BassCliff]

Hi,

Check for spark on all four plugs.


Thank you for your indulgence,

BassCliff

 

[tom203]

Good luck. I read alot of these posts to try and gain knowlege from these guys. I will add my two cents worth. Remember the kiss principle, keep it simple stupid. Start with the easy stuff and go from there. I had a fuel problem, found out my tank was just low on gas while I was putting everything back together, going to reserve fixed that, KISS. Start with the basic stuff and climb out from there. Good luck, sometimes you get lucky and it is the easy stuff...

This is a good thought- this model, especially the L, has small tank. I 've had trouble in hilly terrain running in "ON" when gauge shows 1/4 full. Most of the time I keep it on reserve position .

 

[bigbadwolf]

Well, I don't know what it was in the end. I checked a bunch of electrical stuff and all seemed to run smooth w/out anything else so it must have just been a connection that came loose or something. Spark on all four plugs seemed strong. I yet have to check compression recently but when I originally started haveing problems it seemed to be strong on all cy hovering around 100psi IIRC.

I ran it around and on the highway w out being able to replicate the problem. There is alot of popping on deceleration but that could be due to the screaming eagle harly mufflers I put on. It did have problems at higher speeds and was very hot. the block was at a max temp of 290 F with temps on the pipes near the block around 270 F. It could be that I have to richen my AF mixture or that my petcock wasn't allowing enough fuel to the bowls. That'll have to wait for when i get back. More to follow. Sorry I couldn't sus out anything else yet.

 

[BigD_83]

Well, I don't know what it was in the end. I checked a bunch of electrical stuff and all seemed to run smooth w/out anything else so it must have just been a connection that came loose or something. Spark on all four plugs seemed strong. I yet have to check compression recently but when I originally started haveing problems it seemed to be strong on all cy hovering around 100psi IIRC.

I ran it around and on the highway w out being able to replicate the problem. There is alot of popping on deceleration but that could be due to the screaming eagle harly mufflers I put on. It did have problems at higher speeds and was very hot. the block was at a max temp of 290 F with temps on the pipes near the block around 270 F. It could be that I have to richen my AF mixture or that my petcock wasn't allowing enough fuel to the bowls. That'll have to wait for when i get back. More to follow. Sorry I couldn't sus out anything else yet.

Have you gotten anywhere with this?

Do you get popping from both sides? Popping on decel is a sign of richness IIRC...but overly hot pipes would indicate lean. I could be wrong on that. I'm sure someone else can weigh in on that issue.

electrical problems need to be looked at under the conditions where you are experiencing them. Coil problems seem to hide when cold and show up as they take on more load and heat up.

 

[Stahlgrau333]

I could be wrong as well, but I thought it was the other way around, that 'popping' on decel was a lean condition. That would definitely fit with the other symptoms.

 

[tom203]

I could be wrong as well, but I thought it was the other way around, that 'popping' on decel was a lean condition. That would definitely fit with the other symptoms.

Yeah, ok in Ok. Popping with closed throttle and decelerating (like downhill) means lean. Could just be the finagled airbox and/or mixture screws.

 

[bigbadwolf]

Hey all, nothing more to add to this really other than I did let out the AF screws a bit and it did help w smoother running and less popping. The aforementioned air box "fix" is as follows if anyone's interested and needs a temp soln. Pics to (shamefully) follow. I had the air box that attached to the carbs themselves but didn't have the one that the filter came in but had the filter. Hearing that these bikes were finiky I went ahead and figured out a way to mount the filter to the air box. I had a (don't be too harsh on me...it works pretty well actually) ricotta cheese container that was about the right size and shape. I cut a hole in the lid and used RTV to adhese/seal it to the air box. I then trimmed away the sides of the container itself and placed the airfilter inside. I then close the container and it presses the filter against the lid and the open side of the filter is pressed against the bottom/back of the new air box. It appears to be holding up quite well all things considered. I have put a couple of hundred miles (highway and city) on it so far.

 

[tom203]

Well, I can hardly wait for the pics- I love novel solutions! Ricotta cheese container- high melt plastic I hope. Anyway, put your bike/model/year in your signature in case you update us and we don't remember this.

 

[bigbadwolf]

"Air box" pic

"Air box" pic

As promised here is the "riccotta runner's" air box LOL.

And some misc. pics of the bike while i was fueling

I did find what i think is the right air box on e-bay but I'll be asking about if it is indeed the right one for my bike in another thread.