'80 450 rejetting problems... help please!

[Jward11]

hey guys, i have a 1980 450 (us model) and i'm having trouble finding information on my specific carbs. I have BS34 CV carbs, with the EMGO pods, and custom exhaust with shorty mufflers. the stock main jets were 115, and the pilots were 17.5 and had a huge flat spot at around 3500-4000 rpms. partially occluding the intake pods allowed the bike to run reasonably well with some popping upon deceleration. so i bumped the mains up to 122.5 and the pilots to 20 to flow more fuel, and now it won't idle below 3000 rpms no matter how much i tinker with the throttle stop screw ("mixture screw"), and i can't find an air screw to adjust. wrong jets? do i need to shim the needles? if i do, how? my needles don't have any notches. please help, because i'm about at my wits end...

[BassCliff]

Greetings and Salutations!!

Hi Mr. Jward11,

I'm sorry to tell you that the EMGO pods have a reputation of being pretty much junk. The K&N or APE pod filters are much higher quality and easier to tune. All I can suggest is to try some more jets. Normally, with a modified exhaust and pods, going up 3 or 4 sizes on the mains and 1 size on the pilot jet is a good place to start. To raise the needles, replace the thick plastic washer with a few metal washers from Radio Shack. (Really! They're just the right size.) You'll find lots of GS lovin' on my little website. Let me share some more.

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...

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Thank you for your indulgence,

BassCliff

[pete]

Welcome JWard and good to see another 450 rolling along.

Another member here Flaming Chainsaws recently did a write up on cleaning 450 carbs and he had to drill out some screws that are blocked up on the US models. My Aussie model doesn't have them covered.

The write up should be on BassCliff's site somewhere.

Also, as BassCliff said, the Emgo's do have a bad rep...

I have heard along the way that pods + freer flowing exhaust needs +3 sizes on mains and +1 on pilot, but I haven't done any of that myself yet.

Hope that helps some, but there will be others along who know better.

[Graham]

Just put the 17.5 pilots back in and keep the 122.5 mains. Raise the needle like BassCliff said.

[Dave8338]

In addition, you can oil the Emgo pods a little heavier. Won't hurt a thing.

[Jward11]

Thanks for all the advice. I went and bought some other main jets in various sizes larger than the stock jets. I'm just getting around to trying to raise the needle with some washers. Hopefully that'll do the trick. Sad thing is it just started freezing out here so I can't test ride it at all... Maybe I'll get a sunny break here soon

[hectic_aussie]

I'm in the middle of this too ,pods + 2 into 2 straight through pipes at the moment (not riding)and I removed the air box to put a little box in there for wet weather gear and a clear visor .
since i don't know much on tuning would this ebay item be easier , I ask this cause i see talk on jet size on this forum, but what about the other things this seller talks about (same with the dynojet ones but this is cheaper) , like drilling this and that , is all that really necessary or just jet changing be ok ?

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=230550077430&viewitem=&sspagename=STRK:MEWAX:IT#ht_2666wt_939

my current jet size , from what i can see main says 117 , pilot says 45 .

[pete]

I'm in the middle of this too ,pods + 2 into 2 straight through pipes at the moment (not riding)and I removed the air box to put a little box in there for wet weather gear and a clear visor .
since i don't know much on tuning would this ebay item be easier , I ask this cause i see talk on jet size on this forum, but what about the other things this seller talks about (same with the dynojet ones but this is cheaper) , like drilling this and that , is all that really necessary or just jet changing be ok ?

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=230550077430&viewitem=&sspagename=STRK:MEWAX:IT#ht_2666wt_939

my current jet size , from what i can see main says 117 , pilot says 45 .

Wow that's nuts!! As far as I'm aware, with a freer flowing exhaust and good quality pods, you need to go up 3 main jet sizes and up 1 pilot jet size. There are apparently other things you can do to fine tune such as putting shims or similar in somehow, but I'm nowhere near ready to start looking at that myself yet so can't really comment on the detail.

That eBay deal sounds like way too much overkill and over complication, but I'm probably wrong.

I finally just found the reference as to why I say that, so see if this helps:

http://www.motorcyclecarbs.com/Jetting_Rules_of_Thumb_W43C551.cfm