Dyno Run - 45.1 hp

[octane]

Did the dyno run this morning. The 'ol girl put down 45.1 hp @ 9200 rpm with a really nice, smooth power curve.

She put down 44.0 on the baseline run, but was running real rich. We dropped the main jet to a 124 and moved the clip on the needle to the last slot which evened it out a bit. Now it's lean under 4500 rpm, but it's good from there up, which is where I spend the most time. You can see the A/F on the bottom graph. Ideal A/F Ratio is 12.8-13.2 ppm. On a carb'd motor it's near impossible to keep a straight line, this is a pretty good line that stays pretty close to optimum range. I left the bike at the shop so they could try to dial it in even closer.

The bike has a stock 25,000 mile motor with K&N Stage 3 jet kit (which was too rich the way it came), full V&H exhaust, K&N pod, and Bob Broussard ignition advance.

Graph here: http://octaneonline.com/ipw-web/gallery/GS500/dyno

Haven't gotten a chance to ride the bike yet, hopefully this weekend.

[Juanfer]

45.1 sounds great to me.

Congratulations!

[Briggs]

I am curous, what did it cost you to get it tuned on the dyno. I have gotten mine about as close as I can get it. My next option would be to get it on a dyno.

[miket]

Congrats, those are pretty good numbers!
Are you running the stock pilots? And how many turns of idle screws?

[octane]

I worked out a trade with the shop, so I didn't pay cash. I think it'd be about 75 bucks.

[octane]

Congrats, those are pretty good numbers!
Are you running the stock pilots? And how many turns of idle screws?

Stock pilots, 2 turns.

[The Buddha]

Just as I guessed... lean in the middle... fine lower middle and right up high... I am rich if only slightly all the way across... yea yea I know I know no fancy 45.1 HP... just a seat of pants feel... and My 90 made 43.9 ... but it had 42.5 pilots in it... making it super rich .. 40's made it quite a bit better especially when riding it on the street.... seat o the pants feel.
Cool.
Srinath.

[The Buddha]

TRy stock needles and 150's in the same bike... see what that dyno's to... I can send you a coupon for the dyno run... do it on same dyno too. Rich is better on cold and miserable days like today.
Cool.
Srinath.

[octane]

The butt dyno is the most important tool Srinath!! If it don't feel fast, what good is it??! I gotta pass on the experiment though. The bike has been running all f'd up for a long time. Now that it's right, I'm not so inclined to mess with it. Just want to ride.

[Gisser]

Unfortunately, your baseline run should've been made in stock condition.  Without a before and after, these numbers don't mean much compared to the 39 HP magazine dyno reading of a new GS500.  Ordinarily, a pipe, filter, and jet kit will give about half the 6 HP gain that your report.  But, equally importantly, how would the two graphs compare below peak power :dunno: .

[GRU]

sweet dyno  

i would like to see what happens if you use the stock needles and 150 mains, just like srinath suggested....it would help a lot of us that don't have access to a dyno

did you use a 124 main jet? why so small?

[The Buddha]

Very funny... The case in point is... the vmax with its servo controlled butterflies... 2nd set of butterflies that open at 4500 rpm or so, feels faster to the butt dyno... however on the real dyno and in lap times and drag strip times... the one where the boost is on always works better.. they call that a stage 7 jetting too... However my butt dyno was after an actual dyno... and the flaws in the set up that were pointed out both in power numbers and O2 readings... I corrected and then used a butt dyno... thereby eliminating a false power perception.
Cool.
Srinath.

[Adam R]

The smaller jet is used with the Dynojet needles which are shaped differently than stock.  Therefore you don't need as large a main jet.  

45.1 hp is pretty good for your mods.  The mod. prod race GS's at Willow I'm told have around 46hp (Yoshi pipes, stock motors)

Adam

[octane]

Unfortunately, your baseline run should've been made in stock condition.  Without a before and after, these numbers don't mean much compared to the 39 HP magazine dyno reading of a new GS500.  Ordinarily, a pipe, filter, and jet kit will give about half the 6 HP gain that your report.  But, equally importantly, how would the two graphs compare below peak power :dunno: .

In an ideal world I'd have a stock baseline to go by, but like many of these guys I've been slowly modifying my bike over a period of years as money, time, and confidence in my wrenching abilities allowed.

When I started working on the bike in '96, I didn't have the relationships I have now that allow me to put the bike on the dyno without cash out of pocket - and as a broke 21 year old in '96, $75 might as well have been $750. And back then the idea of pulling my carbs and taking them apart would have sounded like absolute madness. I've done so much since then that not too much intimidates me anymore, as far as fixing/modifying, etc.

Also, as curious as I was to see how much power I was making, I was more concerned with fine tuning the bike and finding out  where it's making the most power before I headed to the track. My buddy has a Bandit 400 that he got a few weeks before I picked up my GS, and he has been spaking my bike for 8 years. It's time the twin put a beating on his little thimble piston'd Bandit! Of course, he just did many of the same mods...so we'll see how that turns out.

[octane]

sweet dyno  

i would like to see what happens if you use the stock needles and 150 mains, just like srinath suggested....it would help a lot of us that don't have access to a dyno

did you use a 124 main jet? why so small?

I started with the 134 main that dynojet suggests, but the bike was running very rich in the midrange, so the tech put the 124 in to even out the mixture throughout the rev range and avoid the A/F spike.

Maybe at some point in the future I'll experiment with the 150 mains and  stock needles. Don't want to wear out my welcome at the shop just yet though.

[The Buddha]

Well I guess if you're not super rich up high... you could lift the needle 1 notch... and make that 1/8th to 1/2 throttle area a bit richer.
Cool.
Srinath.