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Main Area => General GS500 Discussion => Topic started by: boxin on May 11, 2009, 10:41:10 AM

Title: Problems to rejet with UNIFilter
Post by: boxin on May 11, 2009, 10:41:10 AM
Hello. I have a GS500 with 98 stock exhaust and air filter. I bought a UNIFilter foam but I have problems to rejet. Too much air flow, I increased the main jet to 150 (previously 122.5) but still lacking. The only solution was to partially cover the entrance to the filter. Someone had the same problem when using the UNIFilter?
(I apologize for my English which is very basics)
Title: Re: Problems to rejet with UNIFilter
Post by: kml.krk on May 11, 2009, 10:50:43 AM
I think you are trying waaayyy too large main jet. 150 main should be used with K&N Lunchbox and free flowing exhaust. try this post for correct setup: http://gstwins.com/gsboard/index.php?topic=35237.0

good luck and don't worry about your English - it's perfectly understandable!
Title: Re: Problems to rejet with UNIFilter
Post by: boxin on May 11, 2009, 11:01:53 AM
Thanks kml.krk
I read this post and I tried main jets sizes 130, 140 and 150. And it still fails in middle rpm, even with the needle in the highest position. And the fault disappears if cover partially the filter
Title: Re: Problems to rejet with UNIFilter
Post by: drewbytes on May 11, 2009, 01:29:34 PM
From what I've read on here it is difficult to re-jet with a filter with the stock exhaust. Too much air going in with the stock restrictive exhaust. That's why when you partially cover (restrict) the intake it runs correctly.
Title: Re: Problems to rejet with UNIFilter
Post by: The Buddha on May 11, 2009, 01:32:49 PM
Quote from: boxin on May 11, 2009, 11:01:53 AM
Thanks kml.krk
I read this post and I tried main jets sizes 130, 140 and 150. And it still fails in middle rpm, even with the needle in the highest position. And the fault disappears if cover partially the filter


What exactly are you running.
Uni in the air box and stock pipe ... and maybe failing in the mid range is because its too rich.
If you open the throttle and the bike makes soggy power and feels like its trying to get out from under water, that = rich.
Uni in the air box, and stock pipe needs 125 mians and 1 washer ... whoooo ... you said needle in the highest position - you ahve DJ in it, then forget it, no jet changes will work, call DJ for help. Stock needle is 1 position only.
Cool.
Buddha.
Title: Re: Problems to rejet with UNIFilter
Post by: boxin on May 11, 2009, 02:04:10 PM
Buddha: I do not understand well that the "soggy power" and "under water", but i think that is what happens if I am not mistaken.
My needle is the original (stock), I dont have DJ kit, in my country has entered the needle 5-position.
Title: Re: Problems to rejet with UNIFilter
Post by: Affschnozel on May 11, 2009, 02:33:04 PM
I have a UNI filter + stock exhaust with 125 mains , 40 pilot and 3 turns out on mixture screws runs good , maybe a little rich

but no major problems.

Overly rich condition is like this: You open throttle and bike goes brrr brrr brrr   :tongue2:  and then  accelerates strongly
Title: Re: Problems to rejet with UNIFilter
Post by: boxin on May 11, 2009, 06:45:42 PM
So I think it is not my case, when open throttle 3 / 4 the bike does nothing. If open full accelerates like a rocket. If I cover the filter that does not happen and the bike accelerates smoothly.
Note: This exhaust was open because there was something loose inside it making noise, that thing took off and no longer has the same retention gases.
Title: Re: Problems to rejet with UNIFilter
Post by: boxin on May 11, 2009, 09:34:02 PM
Affschnozel, Buddha: Do you mean that the bike bucks when there's too rich?
Title: Re: Problems to rejet with UNIFilter
Post by: boxin on May 11, 2009, 10:13:07 PM
Quote from: boxin on May 11, 2009, 06:45:42 PM
Note: This exhaust was open because there was something loose inside it making noise, that thing took off and no longer has the same retention gases.


I'm explaining this in other words to try and make myself understood.
The exhaust was open because there was something loose inside it making noise, I took the exhaust to a garage because it rattled and they took off the damper, perhaps?? (do you call it like that?) and it no longer has the same retention of gases or fumes"
Title: Re: Problems to rejet with UNIFilter
Post by: natedawg120 on May 12, 2009, 05:56:38 AM
so you are saying that your stock exaust has been cored, as in the baffles have been removed?
Title: Re: Problems to rejet with UNIFilter
Post by: The Buddha on May 12, 2009, 06:50:07 AM
You are sounding lean (cover the filter and it works fine = lean).
Let me read your posts again.
Cool.
Buddha.
Title: Re: Problems to rejet with UNIFilter
Post by: Affschnozel on May 12, 2009, 01:35:46 PM
Anyway , you can always look at your spark plugs to determine if lean or rich
Title: Re: Problems to rejet with UNIFilter
Post by: boxin on May 12, 2009, 08:05:25 PM
Quote from: natedawg120 on May 12, 2009, 05:56:38 AM
so you are saying that your stock exaust has been cored, as in the baffles have been removed?

Exactly.
Spark color is ok.
Title: Re: Problems to rejet with UNIFilter
Post by: boxin on May 13, 2009, 11:04:20 AM
So? If I raise the float level? What do you think?