My GS Chokes

[Gizmoman]

Hi Everyone,

Below is an image of my reworked GS. I have made allot of work on it after it has been sitting for 3 months with no back wheel. I changed the Rear wheel and placed a Katana wheel for a 160 tire, new Exhaust system (Stainless steel), Disk brakes and disks changed, the entire front of the bike has been replaced with a completely new set of parts as well as other modifications.

Now my problem is that after i have finished all the work and started the bike, when i try to accelerate in 1st gear the bike chokes for some time before giving some power.

I have a K&N Air filter, Dyno Jet 3rd stage as well as a new exhaust. The problem was not there before even when i had the Dyno Jet installed and the carbs are perfectly synced with a Carb Tune. All gaskets, seals and everything else inside the carb is completely new (except for the body) and the Mixture screw is set to 3 turns (i played with 2 turns and still the same thing).

Now the only two things i can think of that could cause this is the Exhaust and the fact that i have removed the Clutch cover and the timing poles with it and placed it back on although the iron part is in the notch as it should be.

Can anyone suggest what could be the problem here?

[Big Rich]

Well, if it's choking I'm assuming it's running lean in the midrange. And that would be the needles needing shimmed.

But you say it's doing it in 1st gear- does it only do it in 1st?

[Gizmoman]

It's kinda of doing it if i accelerate fast on the throttle. In other gears it doesn't do it that much but i can still feel it being underpowered.

You mean i should raise the needle by one notch? It wasn't a problem before. This modification, is it required due to a new exhaust system?

[Toogoofy317]

YES YES YES you gotta rejet anytime you go to a K&N filter or new exhaust and a triple Yes if you do both. In the wiki it shows how it should be rejetted!

Mary

[Gizmoman]

Ok, i placed the clip on the needle to the 3rd notch from the top but it seems to got worse and not better. Also i made 3.5 turns on the mixture screw.

[bill14224]

Ok, i placed the clip on the needle to the 3rd notch from the top but it seems to got worse and not better. Also i made 3.5 turns on the mixture screw.

Since your engine is stock I think you may have went too far with the main jets so now it's running too rich when you give it the hammer.  The fact it got worse when you opened the needles another position is my clue.  If I'm right it will run somewhat better if you go back to the stock needle position.  If that holds true you can go to 127.5 or 130 jets at most and it will sing like a bird.  This cylinder head doesn't breathe very well so you don't have to greatly increase the fuel supply, even with improved air filters and pipes.  Having read many stories here about other people's experiences I have come to the conclusion that only small jet changes are needed, not big ones, unless you port and polish the heads.

That said, that is one really nice original naked GS you have there! 

[Gizmoman]

Tnx for the comment

I placed the needle back to the 2nd notch as it was and tightened the mixture back to 3 turns. I had the 3rd stage Jet so it is at DJ134 on Main jets. Straingly it was running fine before. I will open up the carb if i have to but wanted to make sure it's not something i can do without doing that.

The bike was sitting for 3 months so could it of just got dirty inside the carb? I purred some Carb cleaner into the tank (perhaps this helps).

You think i should remove the 134 jet and put the 128 ones?

[Big Rich]

What kind of carb cleaner? If it's the spray stuff that is literally called "carb cleaner", you need to drain your tank. If it was sea foam or something similar then that's ok.

Fresh gas would do you some good anyway.

[Gizmoman]

It's the one you poor into the tank and mix with fuel.

Anyways. I will replace the main Jet with the 128 and see how it goes. Hope all will be well. Will report after i make the changes.

[Toogoofy317]

Here is the wiki but I think it only deals with Mikuni Jets the better ones. http://wiki.gstwins.com/index.php?n=Upgrades.Rejetting

I've heard the DynoJets were not a very good kit but not from my experience!

Mary

[Gizmoman]

Tnx for the link but i already been there. Honestly it didn't help much as my configuration is different. Anyways... I opened up the carburetor and replaced the 134 main jets with 128 size. The performance definitely improved allot. I still can feel a slight choke when i give it the "hammer" but it's almost unnoticeable and since i don't intend to go and race the bike it's good enough for me.

Once again guys i appreciate all the help.