Bonneville America Forums Forums Technical Forums Performance Mods Running Lean or Rich - What are the symptoms???

Ok guys, I need just a little bit of advice about how I can ensure my bike's not running lean.

So I've got Tors, K&N pods, drilled slides, 150 mains, stock needles with one shim, and I adjust my air pilots with the thumb screws to where she runs as well as I can get it.

Now I believe my speedie has never run so well, but would I be right in thinking she is pretty well right in the air/fuel ratio department given she doesn't pop on deceleration, responds really well, the plugs look pretty good and I'm even getting better fuel comsuption than before some of my mods when I knew I was rich. So what else is there besides doing a dyno???? Thanks for any feedback

well if the plugs look good and there is no popping I would say your pilot might be just a touch rich. You should get a little popping on decel with your set up. but it would be not very much , more like a gurgle for lack of a better term. Best way to be sure you are where you want to be at this point is the dyno.

Hey Ian,

it's been a while eh mate?

Ok so you say I may be running a bit rich on the pilot jet side of things which is fine with me. I may do some more tweaking but I just wanted to make sure I'm not running lean given how over time what damage it can do.

Regarding the dyno, I will do one some time soon but until then I just wanted some advice to confirm much the same as what you have said.

Thanks buddy.

I was runnings the same with fishtails (drag pipes). Mine was in the sweet spot. I ran 160's for a while, and was shocked at how much top end HP I gave up.

Yep, good to see you still around. Don't always go by how well the machine runs. A lean engine will run like a scalded cat until it blows up. Not saying thats where you are. From knowing your set up you are probably pretty close if not right on. If your plugs are looking good and it runs well you won't hurt anything. Once you get to that point only way to tweek it in perfectly is the dyno.Just a tad rich won't hurt anything either as long as you aren't getting soot. With no soot you are burning the fuel so are in no danger of loading the oil with gas or washing the cyl. walls clean of lubricant.

I wouldn't mind owning or borrowing a gizmo that could analyse the gas mixture as I went along so there wasn't that doubt or guess work. this one for instance looks ok but does anyone know how good they are from personal use?

Anyway, the other thing I wanted to ask was, when you do a dyno, how many runs do you get for the standard "consultation" (sounds like a doctors appt eh ). I mean, I know the bike will get strapped onto the machine and off we go zooming but it sounds to me like you only get one go at it and if changes need to happen to get everything sorted, I suppose you go home and sort them according to the readout and then come back with another $150 or more bucks or whattever, and start again. Is that right???

Well here it's about $80 give or take for 3 runs. Thats strap the bike in ,get it up to temp, hit the throttle 3 times up to red line. Thats the 3 runs. If you are almost dialed in that should be enough to tweek it or confirm it's where you want it. I was more concerned with my air/fuel mix than HP or torque but was pleasantly suprised at the HP my bike is making. It will tell you if you are lean or rich at any given throttle position and you can adjust accordingly. It will also show any flat spots or dips in HP or torque if thats what you are after.

Thanks Ian. Now I know I can adjust and sort out as best I can my air/fuel ratio, but at the same time hopefully achieve some nice performance numbers too.