Running Lean GS 850

[Skateguy50]

So here is the deal, new to me 850 that was set to run pods and 4-1 but came with carbs back to stock, airbox and stock pipes.

Well the airbox needed boots and took a bit to get on right but is good seal now, the pipes where actually stock for the 850L but fit and run fine.

When I did a few test runs it would start up and idle just fine, when riding it would idle high at stops and after short rides of like 10 minutes or so the pipes would look semi blue up top like its way to hot.

I tried to adjust the air/fuel screw but that really didnt make much a difference. I pulled the carbs and verified it has 115 mains in it, I really do not understand or know much about the needle valve side of the carbs... could that be part of it or would it be the mains?

Oh and PO said the slides might have been drilled but he is not sure... if they where would it cause this issue and if so do I need to replace that part with a stock one? friend in maine has most the parts for these carbs so can get them if needed but the ones on here are super clean so like to make what I got work if I can adjust.

Any help is appreciated, sold the 650 so want to sort this out and get some riding in before I pack up for winter.

[Guest]

You can tell if the slides have been drilled by looking at them. They can be filled with JB Weld and re-drilled.
Check the pilot jet also.
A plug read is better than looking at the pipes but if they are stock headers than blue is bad since I do believe they are double lined.
Are the carbs clean?

[Skateguy50]

Talked to Chris Sorbi tonight and he also said to check the plugs first to make sure that is the issue, but got the carbs off right now so will go through that to make sure then see.

The carbs are super clean, better than I would have done

They dont appear to be drilled and when I took it apart to see about the shim on the needles it did not look to be stock on that. The guide I saw said the shim would be plastic but the one in there was a very thin metal one, so might have been reduced already... I have digital calipers somewhere but not sure where right now...

Anyways done playing for the night.

[Skateguy50]

So still a mystery... carbs are super clean and have the stock mains in and the needles have already been shimmed to be a bit richer not lean...

I checked the orings on the connection to the block and they are new rubber, even has the shiny stainless steel allens on to make it easier to check.

I then went I step further back and verified the air box, the seals on it are good and filter is clean. Its marked for GS750/850 and had the boots for the 750 on it so I sourced the 850 boots and fit them in and they fit tight on the carbs. It would seem the box was last used for a 750 but since it has both factory stamped on it and I have the right boots I dont think that is the issue.

I also pulled the plugs and they are new, and have another new set I can put in... anyways they are very white.

Not really sure where to go next... but it is definitely running to hot but starts up, idles and runs great... thoughts?

[1948man]

Are the plugs the correct number designation for this model? Maybe they're hotter plugs. Is there a chance there is some restriction in the exhaust system? Maybe timing problem?

[Skateguy50]

Ill check the plugs, and when I pull the valve cover off I will verify the timing, didnt think of that.

As far as the exhaust... not sure they are very nice looking stock pipes and sound good when it runs but could be clogged inside perhaps. I will add that to the list.

[Skateguy50]

Bike is sitting under a cover with snow around it... but the carbs are still on the kitchen table (bar). Reading through threads here I realized what drilling the slides actually is and mine might have been from what the PO told me. To make sure I am working with stock I should check and fix that if its the case... and hope it solves my issue.

Anyways I understand I can fill the hole with JB weld and drill it back out, but does anyone know the drill bit size that is stock for the 850, and what size the jet kit might have gone up to so I can see if it was drilled out? I really got no clue what box my digital calipers are in but I have a bunch of drill bits still matched up to size that I can use to check it that way.

Thanks

[Skateguy50]

just a follow up, found a pdf from dynojet that called drilling the slide with a 7/64 drill bit. I will check if that is the size of my hole and know if it was drilled or not. If so still not sure what size to drill it to after filling with JB weld but perhaps they didn't get drilled...

Once that is sorted will put them back on and test the intake boots for leaks, if I find that was my issue and get the carbs back to stock can I do anything for short term to seal the boots enough to synch the carbs? Like would high temp rtv work enough to idle the bike and do the synch? Got Steve coming by on Sunday and want to get full use of his knowledge and tuner. If I need new ones a friend in Maine has some for me but wont have for a few weeks.

[keman]

If it comes down to it, I have two (out of four) un-drilled bs32 slides I can send you. Check your slide diaframs with a light to see if they have any pin holes.

[1948man]

The hole that is drilled out doesn't run straight. Most people, including me don't realize this and try to drill straight in. This often results in an ugly oblong hole on the top side which supposedly doesn't hurt anything. If your top end of the hole is oblong or displaced to the side, that would be a tip that it has probably been drilled. If it looks perfect, it doesn't necessarily prove anything either way.

SORRY, just checked back and I guess you have already considered this. Did you try a 7/64 bit to see if it would fit in?

[Steve]

Got Steve coming by on Sunday and want to get full use of his knowledge and tuner.

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[Skateguy50]

The hole that is drilled out doesn't run straight. Most people, including me don't realize this and try to drill straight in. This often results in an ugly oblong hole on the top side which supposedly doesn't hurt anything. If your top end of the hole is oblong or displaced to the side, that would be a tip that it has probably been drilled. If it looks perfect, it doesn't necessarily prove anything either way.

SORRY, just checked back and I guess you have already considered this. Did you try a 7/64 bit to see if it would fit in?

I looked them over and no clear sign they where drilled, also I didnt have a 7/64 bit but had the next size smaller in my set and that was close to the size of the hole but would not slide in, so no way it got drilled with a 7/64 bit.

So at least I have verified the carbs where set back to 100% stock as I was told. I will get them back on and and test the intake boots, got a friend in Maine with a set of them if that is my issue.