GS450 1982 Jetting sizes?

[drukin]

I have a GS450 with mikuni carbs. I have removed the air box and put on pod filters because the bike is hard tailed now. Anybody have any idea what sizes the jets are in those carbs or what sizes i should go up to?
I only ask cause i dont wanna buy an expensive jet kit when i only need the primaries really.

 

[thevillaindylan]

The stock mains are 115. I'm on the same quest. I've tried 120's and 125's but haven't found the right combo yet.

 

[drukin]

thanks for the info. it seems to run fine until about 65% throttle, so im pretty sure i just need the primaries, but ill get bigger pilots if i can too.
good luck on your journey.

 

[BassCliff]

Greetings and Salutations!!

Greetings and Salutations!!

Hi Mr. ddrukin,

In addition to the pod filters, have you also modified your exhaust? If so, a general rule is to go up four sizes on the mains and one size on the pilots. You'll have to perform plug chops to really dial it in. They are explained on my website. You'll find other carb tuning links too. Let's get started.

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

 

[drukin]

I just did 127.5's in the main and they seem to work perfect for my top end.
now for the pilots. yay!

 

[brad-450Lz]

Hi Druken,

I also have an '82 450 with pods. From what I can tell it's in sore need of a re-jetting. What were your symptoms after adding the pods? Mine starts fine and and idles well at first but hangs around 3500 RPM and won't kick back down to idle once it gets warm ... were you facing the same symptoms?

Glad to hear your having some success ... I'll be getting to my re-jetting as soon as I build up my new ignitor box.

happy riding

 

[Steve]

Can't help much with the jetting, but this statement got me wondering ...

... I have removed the air box and put on pod filters because the bike is hard tailed now. ...

Why is it that if you hard tail a bike that you have to remove the airbox?

Is it just for looks, or is the frame modified so that the stock airbox no longer fits? :-k

Just wondering.

.

 

[67camaro]

There is no room for the air box after it is hard tailed. I'm in the process right now

 

[Guest]

Subscribing to this thread... wanna see how you go with the jet sizes because I hope to go the K&N and custom exhaust route on my '81 450.

 

[Steve]

There is no room for the air box after it is hard tailed.

Thanks.

I have never hard-tailed a bike and hope to never ride one, so I did not know why you had to lose the airbox.
It just opens up a can of worms trying to re-jet properly, good luck.

.

 

[drukin]

The back half of the frame is completely changed and lowered about 7".
dropping is that much leaves room for the battery and thats about it. (between the trail arm and the top of the triangle.)

Anyways, the stock sizes are 17.5 on the pilots and 115 on the mains.
I went up to a 30 on the pilots and 127.5 on the mains.
The motor runs great now. Just had to shim the needle with a few brass washers to richen up the mid throttle.

Attached a photo if anybody is interested.

 

[Guest]

Cool, thanks for sharing the jet details.

Once I get to the point of having carbies in one piece, actually having an exhaust, and having some pods I should be able to at least get a good starting point as it will be the first time I've attempted something like this.

 

[drukin]

shimming the needles is probably the most important.
It controls throttle from about 25% to 75%.
You will need some long slender snap ring plyers to remove the stupid cover they put over the needle. (totally dumb)

Kind of a pain but dont give up, or you will have to run some extra air restriction, which will end up throwing off the idle/full throttle mixtures a bit.

 

[Guest]

Awesome, thanks for the tips.

I'm hoping I'll only be about 3 months away from playing with jetting, but we'll see...

 

[rmathew313]

hey drukin can i ask where u got your jets?

 

[drukin]

local suzuki dealer. DGY motorsports in Downers Grove, IL. had to pull them out to match em up.

 

[rmathew313]

Haha awesome no clue u were from IL. I live in carol stream.... quick question what have u done to your exhaust?

 

[drukin]

its hard to explain. just look at the pics id say. lol

http://www.facebook.com/home.php?#!/photo.php?pid=3692242&id=618617242

 

[atchbo]

Good thread. I've done something similar to my '77 GS400. I chopped my rear end too, but I haven't actually replaced the swingarm yet... just riding rigid struts for the time being. I don't ride it too much or too hard, so I'm not too worried about frame cracking, but I will hard tail it soon.

I have pod air filters too, but I did it a bit differently. I found some hose at a specialty shop that fits the intake side of the carbs just perfectly and extends the intake by about 2 1/2". Then I used some exhaust spacer pipe to extend the intake a bit more and create a hard pipe for my air pods to clamp onto. All told, I've extended the air intake about 4-5 inches, and then the pod filters. This might be overkill but the thinking is that it would smooth out the air flow like the air box used to do. I think my mains are +3 and the pilot +1. I've also got mean straight pipe fishtail exhausts with 8" baffles. It's too loud, but it runs pretty well these days.

I do have a question for any of the gurus which may help me and the original thread writer... right on the transition from acceleration to coasting, at low throttle, I can feel the bike hunting a bit. All in all, I think it's running pretty good, so I won't mess with the carbs again unless I need to, but is hunting (very minor surging) a sign of something... I can't remember.

 

[drukin]

hunting at idle is either gonna be because,
a. pilots are too lean.
b. the single throttle cable is notorious for making it hunt occasionally
c. pilots are too rich. (probably not it in your case)

thats about all i can think that might cause it. or atleast the common causes perhaps.