Here's the configuration:

'06 Heritage Softail Classic
88 c.i.
HeadQuarters 0034 Hurricane cams (chain-driven)
D&D Fatcat exhaust (quiet baffle)
K&N air filter in Roland Sands a/c assembly
Power Commander III

I had the cam installed when the bike had about 25,000 miles on it. At the same time I replaced the original cam shoe tensioners with new ones. The bike ran pretty well but the gas mileage was low at about 30 mpg and I just didn't feel I was getting the best I could out of the bike.

Last week I brought the bike back to the same tuner, now with almost 34,000 miles, and he re-tuned it (only charged me $50 for the re-tune). See the enclosed dyno sheet for results. I'm very pleased with 87 hp and 88 tq for an 88 c.i. engine. But I'm a bit unsure regarding the two air/fuel lines at the bottom of the sheet. Can anyone tell me what the implications of the two lines are in terms of performance? Thanks.

 

Hey, OBP! Im no tuner but I'll be honest!

Looking at your AFR line on the bottom I've gotta say that it does not look right. You probably know that a dyno sheet is basically just a snap shot of what the engine is doing at wide open throttle. So, I dont know that even an experienced dyno tuner can tell you what the guy did that tuned your bike. Whats important to the everyday rider is how the engine performs at various partial throttle postions because thats where you are while riding most of the time, unless you're drag racing. Your peak numbers, as you said, look very good for the components you have. I think at wide open throttle, which I assume this sheet shows, the AFR should be around 13.2:1 all the way through and as you can see, yours looks extremely lean up to 2850 RPM's. Then it becomes very rich up to about 3900 RPM's and finally levels out.
Comparing the old tune (blue lines) to the new tune (red lines), it appears that the only thing that looks better is the AFR at wide open throttle, is better (not as rich) up to around 3500 RPM's and better (not as lean) above 4600 RPM's. Ideally, I think, is a flat line all the way across on the dotted line. Hope this helps and is correct. I'm sure someone with more knowledge on this than myself will chime in. Most importantly, how does it feel to you? Does it run smoothly at all throttle positions and all the way through the RPM range?
Hope all is well over in your neck of the woods.

 

Hi James,

To tell you the truth I don't have a lot of faith in this guy. To answer your question I haven't gotten out on it since the 2-mile ride home Saturday, as we've had record-breaking heat here the past few days (113 degrees in downtown L.A.!), and about 95 degrees is my upper limit for riding if I can help it. I'll get out as soon as it cools off and do a seat-of-the-pants check, though.

Things are good here -- and pretty much as they always are you-know-where. Sometimes it's good entertainment though.

 

If yours is a carb bike, it will not give the straight line air/fuel line that an EFI bike can. This is the dyno graph for my S&S 107 with G carb and you will see close similarities. The dip in the AF curve is a feature of carbs and nothing to worry about! They ain't perfect. If you are happy with the ride your bike gives, enjoy it!

We have had heavy rain all day here in the UK, so stop boasting about having too much sun!

 

To my misfortune, mine's EFI. But I'm still going to take your advice and not worry about it if it rides well. And I'll take too much sun over rain any day, though you're more than welcome to come on over and try out our California weather any time you like!

 

I wouldn't worry at all about the afr line as that is just a tool that helps them to tune, not a be all end all of all stages of rpm tuning. I totally understand you not having faith in a tuner(whomever you used) but if it's running good as you have described I wouldn't go crazy trying to find another shop to have it checked by, I have been there. Just got mine done for the second time in 7 months but the original map was a download(Screaming Eagle Stage III map) and the first tune(dyno shop in the SFV) was 1 pull and he made 1 adjustment(50 dollar dyno tune, he got me 6hp and 8 tq over the downloaded map) and sent me on my way. Bike never ran real good though,throttle response was soggy, so I found a different shop(nearby in Simi) and he uses the factory pro system , don't ask me a whole lot about it cause I don't know what to say about it, other than it's a time consuming process, but it runs real very well and has much better throttle response than before and i did pick up an additional 4 more hp and 6 tq peak.

 

PM sent.

 

Get a hold of Bob Lobenburg, @ RC Cycles, in Hayward.
He will tune your bike to the nines. You'll be happy you went there.
Scott

 

Thank you, Scott. I'll keep them in mind. Considering that they're about 350 miles away, though, it might be a while before I get up that way

 

Only 4 passes between the before/after runs.
Not much tuning could have possibly been done. You likely have some ponies left on the table. And don't expect miracles in the lower ranges.

My bike was tuned in several different RPM ranges and in different gears.
Timing as well as AFR. Each cylinder done separately.
The tuner tried to recreate several different riding scenarios.
It took 67 passes to accomplish this. The bike rides like a dream.

Not much he could have done in 4 passes. I hope he didn't charge you much.