Good dyno results

[rharrison356]

Well, the saga of the XL50 continues. I'll post the dyno test as soon as I get access to the scanner.

With a good baseline of of 59.1 hp and 59.2, torque, the next run was with the SERF. However, during the test, the SERF went belly-up. Neither the dealer nor I am sure what is happening, so we disconnected it for now. I approved the loading of the HD remap ($160 w/tax). Using 4th gear, smoothing 5, the XL50 dyno'd at 72.4 hp and 72.5 torque. That is satisfying increase over the previous "disappointing" results of 62.1 and 62.6 stage 1 results using the SERF. The tech also did a 5th gear run for braggin' rights yielding 76 hp and 80 torque. Not sure why 5th gear provides these "high" numbers, but you can read more about this at http://www.bishopsperformance.com/dynoinfo.htm I regress.

With the stage 1 and HD remap, the Air-Fuel numbers are excellent. I am pleased with the way the bike runs...however, it was really cold outside, so my "seat of the pants" dyno was freezing, nevertheless, here are my first impressions. The bike runs well across all rpm ranges. No hesitation or dead spots. Compared to the SERF (which allows the user to adjust fuel delivery) it does not feel as strong between 3000-4000 back when I was using the SERF and the Big Twin guys tuning help. However, since no-one rides between 3000-4000 all day long, I must say ridability overall is improved and the 4000-6000 range is clearly stronger.

So, what is next? The service manager and I will talk about the SERF issues on Thursday. The dyno tech wants to do a some runs with stage 1, the remap and SERF. The head tech who has talked to HD says our EFI bikes respond well to a one-size larger injector and the SERF...sounds fun...but for now, my wife says "enough."

[07sporty]

My XL1200 Low, has V&H slip-ons, stage 1 air cleaner, and the race tuner
My numbers ended up right at 78hp and 78 torque

[rider29206]

What does SERF stand for?

[rharrison356]

What does SERF stand for?Screamin' Eagle Race Fueler." It's a HD performance part.

[Crusin_w00kie]

My XL1200 Low, has V&H slip-ons, stage 1 air cleaner, and the race tuner
My numbers ended up right at 78hp and 78 torque

I believe Sportin2007 (???) came up with just about the same numbers.

What I'd like to know is this talk about larger injectors and a SERF. Nothing wrong with Mo Powa!!!

[rharrison356]

I believe Sportin2007 (???) came up with just about the same numbers.

What I'd like to know is this talk about larger injectors and a SERF. Nothing wrong with Mo Powa!!!
That might be the ticket to a couple of more ponies...I am not sure how far one can go without doing internal modifications. When I was at the factory, a rep said "larger injectors work" so I am thinking that might be a great way to go. The SERF seems like the right tool for the job. Now if I can only find the time!

[XL50]

RHarrison where ya getting this done? Blue Springs? I live on the other side of the state and have heard they dyno/race tune Vrods/Sportsters there I might make the trip

[rharrison356]

RHarrison where ya getting this done? Blue Springs? I live on the other side of the state and have heard they dyno/race tune Vrods/Sportsters there I might make the tripWorth HD in the north side of Kansas City. They have a brand-new dyno room. I have heard good things about Blue Springs. I know that Gails and Worth are owned by the same folks, and heard (but can't confirm) that Blue Springs is as well.

[XL50]

alright partner I am watching your results very closely and may be making a trip over there with one of the bikes soon

[07sporty]

Has anybody ever tried any injectors yet

[07sporty]

if anyone knows of some that might work let me know I want to try some on mine

[Screw Loose Dan]

I'm maybe a little confused here guys, so please let me know if I didn't follow the thread correctly. But it sounds like you want to put larger injectors on with the other mods being pretty basic (stage 1/2)?

My limited understanding of Fuel Injection tells me that until your injectors can't "keep up", new ones will not do any good. Larger injectors, by themselves, would do no good. My guess is you need to do a lot more work before getting to the point of larger injectors.

It's been referenced all over the place on this forum, but the nightrider .com (http://www.nightrider.com/biketech/motorcycle_efi_basics.htm) states under the advanced EFI page:

Installing larger fuel injectors does not guarantee that power will go up. There are two situations where installing larger fuel injectors makes sense.

1. Your engine is not getting enough fuel at high RPMs and the injectors are at 100% duty cycle. You need larger injectors to make more power.

2. You want to richen the fuel map and do not want to use some of the simpler or more cost effective ways to do this.


Basically, unless you are running lean at WOT you don't need bigger injectors.

But all that being said, I'm sure you can find larger injectors if you want to try it. I'm all for hearing about someone else's experimentation, especially when they are paying for it themselves. ;)

[whittlebeast]

drcstang

You are basicly corrrect. 100% duty cycle is realy about 80-95% depending on the injector design. The injector spray pattern can also get into this mess and is even more difficult to quantify. Generally the more holes in the bottom of the injector, the more fine the fuel spray is. From what I have seen, saw of most of the Harley based EFI software available is rather lame. I don't remember them even showing you the duty cycle. I may have just missed it. There is lots of other things that most of these company don't even address. Harley / Delfi isn't talking so you are left cluless when tuning.

AW

[Screw Loose Dan]

You are basicly corrrect. 100% duty cycle is realy about 80-95% depending on the injector design. The injector spray pattern can also get ino this mess and is even more difficult to quantify. Generally the more holes in the bottom of the injector, the more fine the fuel spray is.

I don't know that I've seen duty cycle either, but I haven't played with the SERT or anything. For some reason I was thinking most "engineered" solutions generally aim for 50% duty cycle, but that is to leave room for growth.

As far as spray pattern, I would agree it is important, but generally not the reason for replacement. FWIW, I remember reading on a BT website somewhere that all the 2007's got much improved injectors as far as spray pattern. Hopefully MoCo got it right the first time with the Sportster injectors...