GStwin.com GS500 Message Forum

I have a 91 rejetted to 140 main 40 pilot lunchbox, vance full pipe, and at sea level.  Where will I stand??? :cheers:

from what I have seen people use a 150 main.

Well I got a 2000 with V&H, lunchbox, and 40/142.5.  It's pretty damn lean, as shown here (http://www.gstwins.com/photogallery/displayimage.php?album=lastup&cat=0&pos=0).

Looks like I'll be going back to the 147.5s...too bad i sold em.

I can get the jets for 2.50 a pop brand new, but just wanted to know if I should go 150 or 140.  I'm gonna run it at a 140 and run new plugs and see how they play out.  Then after a few hundred miles check em. 

Quote from: badguy on October 11, 2007, 07:35:17 PM
Well I got a 2000 with V&H, lunchbox, and 40/142.5.  It's pretty damn lean, as shown here (http://www.gstwins.com/photogallery/displayimage.php?album=lastup&cat=0&pos=0).

Looks like I'll be going back to the 147.5s...too bad i sold em.

put shim under the needle clip..... for transition to the main

also what is different(what was changed---air screw?) between the three runs

140 main will be lean.  I had a lunchbox with a Cobra slip-on, and it was lean.  Vance and Hines flows better than my Cobra.  I'd start with 145's and step up in increments to 150.  When I jumped from 140 to 145, I was good in the midrange but rich up top.  142.5 might have been the ticket, but then I put the airbox back on and tried something different.

Coincidentally, with a Uni in the airbox and a 127.5 main I still ended up slightly lean, but is only noticeable when cold.  I'm thinking of trying to add another washer, or maybe try a 130 main.  I don't think the Cobra flows well enough for the lunchbox to get the jetting lined out.  It's much better with the airbox.  You shouldn't have that problem with the V&H.

Quote from: badguy on October 11, 2007, 07:35:17 PM
Well I got a 2000 with V&H, lunchbox, and 40/142.5.  It's pretty damn lean, as shown here (http://www.gstwins.com/photogallery/displayimage.php?album=lastup&cat=0&pos=0).

Looks like I'll be going back to the 147.5s...too bad i sold em.

Uh, are you serious? You are MAJORLY rich on that dynorun.  :icon_rolleyes:

Quote from: slowinthestraights on October 11, 2007, 09:04:29 PM

Quote from: badguy on October 11, 2007, 07:35:17 PM
Well I got a 2000 with V&H, lunchbox, and 40/142.5.  It's pretty damn lean, as shown here (http://www.gstwins.com/photogallery/displayimage.php?album=lastup&cat=0&pos=0).

Looks like I'll be going back to the 147.5s...too bad i sold em.

Uh, are you serious? You are MAJORLY rich on that dynorun.  :icon_rolleyes:

Yeah, I don't read a lot of dyno graphs but I'd say that you were rich as well, which may change my original post on this thread.  Anyway, the y-axis on the bottom graph says AIR/FUEL so a smaller number would signify less amount of air per amount of fuel.  There are no units on the axis so I don't know what the amount actually is.  Regardless though, taking the graph at face value it definitely says rich.

That is very interesting to me.  Badguy, what do your plugs look like?  WIth 140 mains my plugs were okay, but looked a little white which I took to be slightly lean.  I would assume that yours would be the same with 142.5's and V&H exhaust.  Now I'm thnking I should have tried going down with my mians instead of up.  Man, color me confused.

Bombadillo, ignore my post earlier.  It would appear that I have no clue about what I am talking about.

excellent!   :laugh:  All posts ignored

Quote from: DrtRydr23 on October 11, 2007, 09:19:52 PM
Yeah, I don't read a lot of dyno graphs but I'd say that you were rich as well, which may change my original post on this thread.  Anyway, the y-axis on the bottom graph says AIR/FUEL so a smaller number would signify less amount of air per amount of fuel.  There are no units on the axis so I don't know what the amount actually is.  Regardless though, taking the graph at face value it definitely says rich.

That is very interesting to me.  Badguy, what do your plugs look like?  WIth 140 mains my plugs were okay, but looked a little white which I took to be slightly lean.  I would assume that yours would be the same with 142.5's and V&H exhaust.  Now I'm thnking I should have tried going down with my mians instead of up.  Man, color me confused.

Bombadillo, ignore my post earlier.  It would appear that I have no clue about what I am talking about.

Critical thinking FTW!!!

That's what I get for listening to the guy at the shop instead of thinking...I'm pretty sure you and Mr. slow are right. I guess I just took the guy's comments for granted and assumed that the plot was fuel/air instead of the other way around - didn't even look at the label.  I'm confused too  :icon_confused:

As for my plugs, I checked them when I had 140s in (did a plug chop on a nice straight back road) and they led me to believe I was running lean (looked the way you describe), so I moved up to the 142.5s.  Now the dyno suggests that I'm super rich (HA, I wish!) and the guy at the shop says they can tune it for $275.  While that sounds like a decent price, I don't think I want a guy who can't read a dyno (other than me) to be tuning my bike.  I tried asking him for advice on doing it myself and he didn't really have much to say.  In his defense, he wasn't the one running the dyno, so maybe he just does mechanical work and has no clue as to the combustion side of things.  I should've asked the other guy.

Anyway, I'm not sure what I'm gonna do now.  It's time for some thinking.  I have the stock mains still, so maybe I'll put those in for the hell of it and do a plug chop.  It's funny, at one point I had 147.5s in there and it just felt rich.  I'm no expert, but something just didn't feel right when I whacked it open, so that's why I moved down to the 140s (that and reading about dgyver's project). 

werase: These runs were just hp pulls for a contest instead of tuning/diagnostic runs (I assume there's a difference).  From what I could tell, it was just WOT the whole time, which I thought was mostly affected by the size of the mains  :dunno_white:  Anyway, if this shows that I'm running rich, wouldn't I want to pull one of the shims out (I have two washers under each needle)

EDIT: bombadillo - sorry for hijacking the thread, maybe something useful will come out of it. 

Yes, you are majorly rich there. It dips down to 8:1 9:1 there for a bit. 13 something is ideal, and you should be very safe at 12.5~ all the way up the graph.Take this for EXAMPLE. I have k&n lunchbox, yoshimura full exhaust, I am on 135 mains and still rich.

Yeah, it's just funny how many different opinions there are on jetting.  It would be nice if I had someone nearby who knew what they were doing and I could work with them to get it right.  But it's all trial and error on my part, and I'm not the best with the diagnosis (evidently...looking at the plugs I thought I was lean at 140).  Anyway, we'll see what happens with the stock mains back in there before I go spending any more money.  Thanks for the insight :cheers: