Just rebuilt Carbs on my gs850g, bogging.

[NOS]

I got her carbs back together after the rebuild and i filled the carbs with gas and turned the key. WOW she started right up! She never started like that before! The idle is so nice she sounds like a monster! Nice idle. I turned it off and she start up again on the first crank.

So here are the problems:

#1 It idles fine but when i give it gas she wants to die, i cant turn the throtle at all, not even a lil bit.

#2 I let er idle for about 4 minutes and the header started getting too hot and smoking.

#3 I was getting a lot of backfiring.

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Changes made during the rebuild:

I change the main jet to 130 (to compesate for the new pods and new V&H Exhaust 4-1 that i dont have yet).

I am running no air filter (i left the filter off in case i needed to pull the carb out again).

I am running stock exhaust. (saving up for my V&H 4-1).

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I am contemplating going back to the old main jets 115 till i get the V&H. Does anyone know if the 115 will work ok with the pods? Should i try a 120 main jet? I know this question has been beat to death but i cant find a solid answer on the jet size because everyone says to get the Dyno Jet kit! But i dont want the kit i just want to buy the correct jet! Thanks!


P.S. After some more research i think im going to try to turn the Air Fuel Mixture screw all the way down while the engine is running. I havent even touched the A/F screw after the new jets were installed. Hopefully tunning it like this will solve the problem.

 

[Steve]

So here are the problems:

#1 It idles fine but when i give it gas she wants to die, i cant turn the throtle at all, not even a lil bit.

#2 I let er idle for about 4 minutes and the header started getting too hot and smoking.

#3 I was getting a lot of backfiring.

#1. You answered that a few lines later in your post, but did not realize it.

#2. You expected it to be COOL after four minutes of running?

#3. Backfiring is a symptom of running lean. Could be your idle mixture settings or a bad carb sync.

I change the main jet to 130 (to compesate for the new pods and new V&H Exhaust 4-1 that i dont have yet).

I am running no air filter (i left the filter off in case i needed to pull the carb out again).

I am running stock exhaust. (saving up for my V&H 4-1).

The only time you should change the jets that much before changing to thte pods and pipe is if they are NEXT on your list and you do not plan on riding the bike until you do so. That jetting will make the bike VERY hard to ride.

Running with no air filter is why you can not give it any throttle. It is necessary to have SOME restriction on the intake for the vacuum slides to work properly. To verify this, simply fold a shop rag in half, place it over the carb intakes. Clamp it to the two outer carbs with hose clamps or zip-ties. Your bike will run like a scalded dog. This is even good enough for a test ride, but is not good enough for jetting checks.

Again, if you are still running stock intake and exhaust, run stock jets.

I am contemplating going back to the old main jets 115 till i get the V&H. Does anyone know if the 115 will work ok with the pods? Should i try a 120 main jet? I know this question has been beat to death but i cant find a solid answer on the jet size because everyone says to get the Dyno Jet kit! But i dont want the kit i just want to buy the correct jet! Thanks!

I don't know what you will need with your off-brand pods, but it will likely be larger than 120.

Yes, the question has been "beat to death", but we are trying to prevent the death of your engine due to your stubbornness. As I mentioned in your first carb thread, it's not the jets that make the DynoJet kit worth the money, it's the NEEDLES.

P.S. After some more research i think im going to try to turn the Air Fuel Mixture screw all the way down while the engine is running. I havent even touched the A/F screw after the new jets were installed. Hopefully tunning it like this will solve the problem.

Did you even bother to read the carb cleaning guide?

I am thinking that you just glossed over it, catching the parts that you wanted and skipped the rest, thinking "oh, that doesn't apply to me". Guess what? It DOES apply to you.

How can you say with a straight face that you have not moved the idle mixture screws, when you said earlier that your "rebuild is done". Doing a proper rebuild involves removing that screw before dipping the carbs to clean them, then replacing the o-ring that is sealing that screw when you re-install it.

Set the mixture screw anywhere you want (since you are ignoring everything else we are suggesting), but the proper setting to start with is about three full turns out from lightly seated. When the engine is fully warmed up, turn the screws in slowly, listening for a slight drop in engine speed. When you hear that drop, back up about 1/8 turn, go to the next carb. Repeat until all are done.

Don't forget the carb sync will the manometer.

.

 

[NOS]

I am thinking that you just glossed over it, catching the parts that you wanted and skipped the rest, thinking "oh, that doesn't apply to me". Guess what? It DOES apply to you.

How can you say with a straight face that you have not moved the idle mixture screws, when you said earlier that your "rebuild is done". Doing a proper rebuild involves removing that screw before dipping the carbs to clean them, then replacing the o-ring that is sealing that screw when you re-install it.

Set the mixture screw anywhere you want (since you are ignoring everything else we are suggesting), but the proper setting to start with is about three full turns out from lightly seated. When the engine is fully warmed up, turn the screws in slowly, listening for a slight drop in engine speed. When you hear that drop, back up about 1/8 turn, go to the next carb. Repeat until all are done.

 

[Guest]

Like Steve said, it wont run without an airbox unless ya rejet.
You're chasing your tail if you even try to make it run without an airbox.

 

[cowboyup3371]

Listen to what you are being told here. These folks have not steered anyone wrong IF the individual does what is suggested.

 

[NOS]

Owner of a 1981 GS550T with 77-78 GS750EC Front Forks

I signed the Remember Alex Brown (RAB) DNT TXT N DRV pledge, will you?

 

[NOS]

I'm sure you could manufacture some killer needles if you had the specs. I doubt that Dynojet publishes that kind of information so you'd have to get some originals to make copies. I suppose as long as you didn't sell them it wouldn't be illegal.

Octain, I tend to agree with TCK. Those don't look tapered enough to be DJ needles. But the notches at the top make tuning the midrange so much easier.


Thank you for your indulgence,

 

[Guest]

Ok i dont know how everyone got so confused, i have air pods I have re-jetted!

I ran it without the pods, ill put them on, no big deal! That will solve everything right!!!!!

Nope, should run fine with or without the pods if jetted correctly.

 

[NOS]

#1. You answered that a few lines later in your post, but did not realize it.

#2. You expected it to be COOL after four minutes of running?

#3. Backfiring is a symptom of running lean. Could be your idle mixture settings or a bad carb sync.

 

[JEEPRUSTY]

Do you guys giving me advice even have any experience manually tunning carbs?

YES you can run a bike without a air filter: http://www.youtube.com/watch?v=epvROXTPcUY&feature=related

Most race bikes run without a filter.

That is still a function of jetting and exhaust
dude put on yer pods and go from there.

 

[rustybronco]

You need to jet for what you have, not what you intend on doing in the future!

 

[NOS]

Nope, should run fine with or without the pods if jetted correctly.

I'm sure you could manufacture some killer needles if you had the specs. I doubt that Dynojet publishes that kind of information so you'd have to get some originals to make copies. I suppose as long as you didn't sell them it wouldn't be illegal.

Octain, I tend to agree with TCK. Those don't look tapered enough to be DJ needles. But the notches at the top make tuning the midrange so much easier.


Thank you for your indulgence,

 

[Guest]

Do you guys giving me advice even have any experience manually tunning carbs?

YES you can run a bike without a air filter: http://www.youtube.com/watch?v=epvROXTPcUY&feature=related

Most race bikes run without a filter.

Sure ya can, IF JETTED FOR IT.

www.denniskirk.com

Buy a jet kit! It comes with an adjustable needle.

 

[NOS]

Sure ya can, IF JETTED FOR IT.

www.denniskirk.com

Buy a jet kit! It comes with an adjustable needle.

I'm sure you could manufacture some killer needles if you had the specs. I doubt that Dynojet publishes that kind of information so you'd have to get some originals to make copies. I suppose as long as you didn't sell them it wouldn't be illegal.

Octain, I tend to agree with TCK. Those don't look tapered enough to be DJ needles. But the notches at the top make tuning the midrange so much easier.


Thank you for your indulgence,

 

[Guest]

Did you compair the needles when you got your needle kit? How was the angle was it more tapered or less? I would rather just try to make my own needle, if i fail i could buy a kit. But since i could probably make all 4 needles in 5 minutes id rather try that first. I have a drill bit grinder here in my shop and then i could polish the tips. Thanks for your help.

Other than the obvious multiple notches they have a different tapper on the pointy ends.
I think the most important part is the notches to adjust the height of the needles. This is where you're seeing your issues right now.(just off idle)
The slide will also need to be drilled.

Spend the hundred bux dude, you wont regret it as long as you follow the oh so important instructions that come with the kit.

<<Wait i know the answer.... BUY A KIT! ... yeah but id rather know whats going on since i will probably be changing the cams and rods and the pistons and id rather know what im doing than just bolting on a kit someone pre-made for a certain stage.>>

Edit in reply to your edit..
Then dont buy the kit and spend your entire summer trying to get your bike running right.

 

[JEEPRUSTY]

Did you compair the needles when you got your needle kit? How was the angle was it more tapered or less? I would rather just try to make my own needle, if i fail i could buy a kit. But since i could probably make all 4 needles in 5 minutes id rather try that first. I have a drill bit grinder here in my shop and then i could polish the tips. Thanks for your help.

Wait i know the answer.... BUY A KIT! ... yeah but id rather know whats going on since i will probably be changing the cams and rods and the pistons and id rather know what im doing than just bolting on a kit someone pre-made for a certain stage.

Mine came witht he sewing machine.

It was a nice singer pedal model.
In fact everyone in my family was a singer. Even the sewing machine.

 

[TheCafeKid]

NOS

You clearly aren't listening. You can try to make needles. Have at it. Anyone with a lathe could make them. But how do you know what you are doing? Is the taper to slow? To fast?
The kit was made by professional tuners who spent many many many hours designing them, trial and error, etc etc to get them right.

Your example of a race bike running without an air filter is neither here nor there. They've been jetted for that set up. That's the reason they run. You changing jets doesn't amount to a hill of beans. The jets are SECONDARY in importance compared to the needle.
Btw if you're building a "race bike" you've chosen a poor platform for it. The heaviest GS made, plus a shaft drive? C'mon man.
Yes. Spend the 100 bucks. Buy the damn kit or ride around till you torch the valves. Good luck

 

[Guest]

You can buy a kit and it will save you for a day or you can teach someone how to make their own kit and feed them for a lifetime.

Reply to yet another edit

I dont know how to make a kit. Hence the reason I purchased mine from the site I provided.

Here are some pics of the needles.(yes I went out to my garage, pulled my box of carb parts off the shelf just to snap a pic or two just for you) The one on the left on the top pic is the Mikuni OEM(stock) needle removed from the CV on my 82 850. The one on the right is a DJ needle. Note the notches? This is what ya need more than anything. That is, if you want your bike to run right.

 

[TheCafeKid]

Reply to yet another edit

I dont know how to make a kit. Hence the reason I purchased mine from the site I provided.

Here are some pics of the needles.(yes I went out to my garage, pulled my box of carb parts off the shelf just to snap a pic or two just for you) The one on the left on the top pic is the Mikuni OEM(stock) needle removed from the CV on my 82 850. The one on the right is a DJ needle. Note the notches? This is what ya need more than anything. That is, if you want your bike to run right.

Todd you sure those are DJ needles? Doesn't look like any recent needles I've seen from them, but admittedly I've not seen them all. Looks as though they could be Canada spec stockers. Every DJ needle I've seen is way sharper... Just saying. I could be and possibly am totally wrong.

 

[Guest]

Ya know what? Im not totally 100% positive. I bought em with a large DJ parts lot that I just assumed were also DJ. But the needles were the only parts that werent bagged in DJ packaging.
I'm not removing the needles from the 850 to compare either.
I was mainly just trying to show him the notches.