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Main Area => General GS500 Discussion => Topic started by: skudman on August 26, 2012, 12:22:14 PM

Title: runs really rough...where to start?
Post by: skudman on August 26, 2012, 12:22:14 PM
06 GS
rejetted (147.5/75/20)
luchbox
yosh pipe
2 turns out

-Runs good when hot, only complaint when hot is slight boggyness from 2k-5k pulls real hard after that.
-Runs awful when she is cold or less than 1/2 operating temperature. Pops, sputters, hesitates under light to mid throttle,

Smells of fuel while idling always, got a little something out the tail pipe last night, but it was dark so I could only see a light smoke puffing out upon revs, reeked of fuel.

I recently switched the mid main from what the shop put in a 130 to the 75, but honestly she seemed to run better with the big midmain. Perhaps another 1/2 tun out? needle height? Float check?

:icon_question:

Title: runs really rough...where to start?
Post by: cbcanada on August 26, 2012, 09:27:26 PM
sounds like you are lean to me ..
Title: Re: runs really rough...where to start?
Post by: ggg on August 27, 2012, 09:29:57 AM
According to the wiki (http://wiki.gstwins.com/index.php?n=Upgrades.Rejetting), skudman's main and mid-main are firmly on the rich side. I'd say replicate the configuration from the wiki table and see how it goes...
Title: Re: runs really rough...where to start?
Post by: lamoun on August 27, 2012, 09:46:42 AM
Oh yes.. the elusive mid main..
The mid main is only for the choke. If you take the carbs at hand and look/blow at it you will understand what is going on.

Now when I got the lunch-box + full jardine exhaust I used 142.5 main and it ran quite well. I can't say if it wasn't rich/lean for sure (I thought it was on the rich side), but it surely wasn't running rough.

Then there is that..

Quote from: skudman on August 26, 2012, 12:22:14 PM
-Runs good when hot, only complaint when hot is slight boggyness from 2k-5k pulls real hard after that.
-Runs awful when she is cold or less than 1/2 operating temperature. Pops, sputters, hesitates under light to mid throttle

A lean problem gets better as the operating temperature increases, since the air became less dense (less air).

My first step would be to check for an air leak using either WD40 (rpm drop) either ether (rmp rise - be careful)
Title: Re: runs really rough...where to start?
Post by: jestercinti on August 27, 2012, 10:28:33 AM
Quote from: skudman on August 26, 2012, 12:22:14 PM
06 GS
rejetted (147.5/75/20)
luchbox
yosh pipe
2 turns out

-Runs good when hot, only complaint when hot is slight boggyness from 2k-5k pulls real hard after that.
-Runs awful when she is cold or less than 1/2 operating temperature. Pops, sputters, hesitates under light to mid throttle,

Smells of fuel while idling always, got a little something out the tail pipe last night, but it was dark so I could only see a light smoke puffing out upon revs, reeked of fuel.

I recently switched the mid main from what the shop put in a 130 to the 75, but honestly she seemed to run better with the big midmain. Perhaps another 1/2 tun out? needle height? Float check?

:icon_question:

20 Pilot - Good
75 Mid-Main - WAY TOO RICH.  Try 65.
147.5 - Probably slightly rich.  Maybe 145?

Change 75 to 65.  I think that's your issue there.

Title: Re: runs really rough...where to start?
Post by: The Buddha on August 27, 2012, 10:35:14 AM
75 is far too much, 60 - back to the stock size and try 1 washer under the needle ...
147.5 is fine.
2 turns is rather low, try 3.

However I cant imagine you are lean with 75 mids ... maybe @ idle only, the mid range you are super super rich - maybe that bogging in the 2-5k is that.

Cool.
Buddha.
Title: Re: runs really rough...where to start?
Post by: jestercinti on August 27, 2012, 12:22:01 PM
Skudman, my setup and jet settings are in my signature if you want to use as a reference.  I am very happy with my setup.  I have a lunchbox, but stock exhaust.

Jetting is a black art, and your setup and my setup will vary based on temperature, elevation, humidity, etc.
Title: Re: runs really rough...where to start?
Post by: craigs449 on August 27, 2012, 01:35:43 PM
If it smells of fuel, you are running rich......