Stock Dyno Run

[bargovic]

So the hp, and torque graphs are showing peak performance around 8k.   But what is the air/fuel graph suppose to tell me.. seems like the ratio is bouncing all over.. is this a typical result graph? ive never see the air/fuel graph before. what info do i want from the ratio graph?

[dbarile]

I don't recall anyone advocating 140 sized mains on a stock bike. The matrix I have says 125. 'Optimal mixture' may be open to SOME interpretation.  

Before we have a 'discussion' about the jetting matrix, I going to clearly say I don't know if it is correct or not. I'm not defending it, but I am citing it as others here have done. My view is that it is a starting point and nothing more. It does seem to be correct on about the idle jets though. I have a set of 40's I haven't installed. It might be interesting to see the mixture after only the idle jets are are changed.

The guy who dyno'd my bike implied that he was more interested in stable mixture over the entire range. Obviously he wasn't talking about 15, but he seemed more intrested in obtaining a straight line 'near' the optimal. He didn't say that but that was my impression. Next time I see him I'll ask him straight out.

I think the one place I might take issue with is the exhaust. If your muffler is restrictive then changing it will certainly free up the engines breathing apart from the pipes.

As far as your bike goes, it might be interesting to see a dyno run on that as well.  Where did you get the 137.5 from?

[dbarile]

So the hp, and torque graphs are showing peak performance around 8k.   But what is the air/fuel graph suppose to tell me.. seems like the ratio is bouncing all over.. is this a typical result graph? ive never see the air/fuel graph before. what info do i want from the ratio graph?

I understand that this is pretty typical for a stock GS500.  I think the info you need is that the mixture needs to be richer at the low end and better controlled across the whole spectrum.  Ideally you want the mixture at optimum across the whole range.

[Alphamazing]

I've got an '04, so the carbs are different. I've got a mid main jet and a different pilot jet. The consensus, not only by the matrix but in the FAQ section about jetting here on the board, is still to increase the mains and mid mains more than a few number of sizes. There are some who even say that you need a 150 main on the old bikes... Honestly. A 150. That's absurd. Hell, a 140 is absurd. Mine is rich right now and it's a size down from that. My stock numbers are 130/60/17.5.

I bumped the main up 3 sizes, the mid-main up one size, and the pilot up one size, per the instructions in the FAQ and the jetting matrix.

My gas mileage is also crap-tastic now. I'm getting low 40s. I used to get mid 50s.

[dbarile]

I've got an '04, so the carbs are different. I've got a mid main jet and a different pilot jet.

Yea. I knew that your carb and mine were different. I'm only looking at the matrix for my carbs. And I think I agree that a 140 or 150 jet would be too much.

My gas mileage is also crap-tastic now. I'm getting low 40s. I used to get mid 50s.

If you rejetted for the cold start deal, maybe you should go to stock on the main and mid and keep the modified idle. Of course you have the K&N deal going on so you might want check for top end lean condition once you go back.

Again, I'd really like to see a dyno run on your setup, but not to the point of financing it.  

[Alphamazing]

Yeah yeah. I'm just gonna bump the main and mid main back to stock. I might even bump the pilot jet back to stock, but leave the screw to 3 turns out. The place I was gonna get my bike dynoed at closed, so no more $20 dyno runs for me. I'll find a new place eventually.

[The Buddha]

150 on a bike with K&N pod filter - no airbox and pipe.
125 on a stock.
127.5 on a K&N in airbox.
89-00 bikes.
Cool.
Srinath.

[dbarile]

One of these might be semi-near you.


http://www.dynojet.com/maps/bikedynos/tx.htm