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[skyhook]

Just got back from the builder/machinist's shop.  Gave him a down payment to get started on a new build.  I've got an '05 road king classic with a 103" and I'm over it!  The new build is:
stock cases, bored to accept 4&1/8" cylinders
screamin' eagle forged 4&3/8" flywheel and rod assembly, welded and balanced
screamin' eagle 264 cams ('cause I already have them, they're paid for!)
new cam chain tensioners, changed at 12k, now have 33k on bike
jims powerglide lifters
crane chromoly adjustable pushrods
stock cylinders, sleeve removed, resleeved with a ductile 4&1/8" one
custom pistons, maybe dished
screamin' eagle performance heads, hand ported and flow tested, wallowed out to 90cc total chamber volume(including dished piston), 2.0 intake valve, 1.623 exhaust valve
.040" mls head gaskets, I wanted .030 but I defer to the maestro
roller rockers
? valve springs
 stock throttle body and manifold, bored and port matched, maybe larger injectors
power commander
screamin' eagle clutch spring
we're undecided on exhaust, I want supertrapp, builder says primaries too small
he wants thunderheader, I say too f'ing loud!
I've got rinehart 2 into 1 on there now, may get cheap and just take the baffle out and run it and get earplugs!

Any suggestions on injectors?

[Unbalanced]

Don't know of any choices on the injectors other than stock 4.35 on the 25 degree injectors or 6.22 yellow bands for the 05.

[grc]

Don't know of any choices on the injectors other than stock 4.35 on the 25 degree injectors or 6.22 yellow bands for the 05.

If you plan to stay with the stock throttle body, the 25 degree injectors are not an option (they fit the '06 and later TB, but not the '05 and earlier).  As for higher capacity injectors, I believe H-D sells a Screamin' Eagle version, and this place has a couple of larger sizes also.
http://www.injector.com/harleyinjection.php

Jerry

[Unbalanced]

Jerry,

Thanks for the link, I had not seen another injector for the 05's other than the yellow band or the 6.22 gm/sec.   I wish they would tell you what the flow rate was on the stage1 or stage2, because I believe the ones I got through harley were actually the V-Rod ones (named as yellow band).

Some things to note from Marren,

You have to choose the injector by cylinder horsepower at the CRANK not the rear wheel and you may have to play with the gm/sec slightly depending on each bike.  They could not give me cross reference parts or similiar which was a bit tough to understand and when asked what the gm/sec were on the injectors they said you could not do it that way until you bought the injectors as they come with a computer read out from the matching and that would tell you what to set the gm/sec at for the injector.   You would be close they said by figuring out the crank HP for the motor and buying that way.

was kind of confusing when you associate it from the way they do it to trying to convert it for use on a harley.

btw 06 go from roughly stock at 3.89 to almost 5.9gm/sec on stage 1 and almost 8 gm/sec on stage 2

Skyhook you're going to have to figure out what your target horsepower is and buy injectors accordingly, sorry that was as much as they could help or do what did and go with the harley ones that are 6.22gm/sec.   I believe a few guys here are running those same injectors on their bikes.   

[bdas2]

had to ask...........whats a ball park figure for this

[Talon]

Stock injectors should be good, after the build, check the duty cycle on the injectors. You might want to look at Hoist Cybil RK build for the TB, might want to go bigger, and in that case many come with injectors.

Larger injectors typically are required for applications exceeding 130 hp. In these cases use the stock V-rod (VRSCA) injectors, good to 170hp.

 V-rod injectors p/n 27665-01

Formula for injectors, based on 120hp:
The formula for calculating injector size; HP x BSFC (brake specific fuel consumption, typ. .50) / 2 (number of injectors) x .8 (duty cycle). Your motor would calc. to 120 x .5 = 60 / 2 x .8 = 37.5 lbs/hr or 4.72gm/sec.

[Unbalanced]

Stock injectors should be good, after the build, check the duty cycle on the injectors. You might want to look at Hoist Cybil RK build for the TB, might want to go bigger, and in that case many come with injectors.

Larger injectors typically are required for applications exceeding 130 hp. In these cases use the stock V-rod (VRSCA) injectors, good to 170hp.

 V-rod injectors p/n 27665-01

Formula for injectors, based on 120hp:
The formula for calculating injector size; HP x BSFC (brake specific fuel consumption, typ. .50) / 2 (number of injectors) x .8 (duty cycle). Your motor would calc. to 120 x .5 = 60 / 2 x .8 = 37.5 lbs/hr or 4.72gm/sec.

Well that calculation throws a monkey wrench in the works because depending on year the stock injectors only put out 4.22 in 05/06 and 4.35 in 01-04 map at least per harleys measurements in the race tuner.

The only way I have at home to test the load is to use a power commander and zero out all the tables while using a SERT map in the ECM and use that to check duty cycle on the injectors to do it myself.

The 07 injectors that come in with the 50mm throttle body do not work with the 05 bikes off the shelf anyhow and they are 4.89 gm/sec

Cal #21 -- 105LL005-D1.MT6  01-04
               141PD004-A2.MT6  05-06

These are both 1690 high output as a sample for the injectors and output.



For those wondering how Talon got to 4.72 gm/sec

37.5 lbs x 453.59    where 453.59 grams = 1 pound converted to grams   

so (37.5 lbs x 453.59) / 60    = grams per minute   or 17009.625

Take the grams per minute and divide that yet again by 60 and you will have grams per second.

170009.625 / 60 = grams per second.

[Twolanerider]

There are days when Arlo Guthrie just goes wandering through your head.... 

[Talon]

Well that calculation throws a monkey wrench in the works because depending on year the stock injectors only put out 4.22 in 05/06 and 4.35 in 01-04 map at least per harleys measurements in the race tuner.

The only way I have at home to test the load is to use a power commander and zero out all the tables while using a SERT map in the ECM and use that to check duty cycle on the injectors to do it myself.

The 07 injectors that come in with the 50mm throttle body do not work with the 05 bikes off the shelf anyhow and they are 4.89 gm/sec

Cal #21 -- 105LL005-D1.MT6  01-04
               141PD004-A2.MT6  05-06

These are both 1690 high output as a sample for the injectors and output.



For those wondering how Talon got to 4.72 gm/sec
37.5 lbs x 453.59    where 453.59 grams = 1 pound converted to grams   

so (37.5 lbs x 453.59) / 60    = grams per minute   or 17009.625

Take the grams per minute and divide that yet again by 60 and you will have grams per second.

170009.625 / 60 = grams per second.

Correct, it does show a little higher, but talked to several tuners and they say that the stock work fine up to 130hp, they say if the calculation numbers were a lot higher then you would want to look at bigger injectors, but that injectors aren't going to exactly match the calculations.

Unbalanced, is correct about the calculations, we use this for figuring out stroker jeeps, but is in gal per minutes.

Looking at you duty cycle will also let you know when a bigger injector is needed if you cycle is to long you need larger injectors, like unbalanced said. I haven't used the PCIII to do this, but will try when I get mine installed.

[Unbalanced]

Nidan,

I believe if the builder does it right he will have to look at larger injectors just like Howie ended up doing.   Look at Howies they almost could get away with the stock ones but actually couldnt due to the build and that was 110 not 117 and the numbers were 126/120 while I agree they had a large throttlebody and air cleaner the duty cycle was in Joes opinion too high to not go larger.   In this case depending if lets say they get 10 percent over in numbers that is 128 / 128 for sake of arguement that would put him in the same boat as Howie depending on throttle body.   Until it is actually built and someone can duty cycle the motor / injectors it is going to be a best guess, but personally if I am pushing constant 65-75 percent utilization I am going larger.   

[Talon]

Nidan,

I believe if the builder does it right he will have to look at larger injectors just like Howie ended up doing.   Look at Howies they almost could get away with the stock ones but actually couldnt due to the build and that was 110 not 117 and the numbers were 126/120 while I agree they had a large throttlebody and air cleaner the duty cycle was in Joes opinion too high to not go larger.   In this case depending if lets say they get 10 percent over in numbers that is 128 / 128 for sake of arguement that would put him in the same boat as Howie depending on throttle body.   Until it is actually built and someone can duty cycle the motor / injectors it is going to be a best guess, but personally if I am pushing constant 65-75 percent utilization I am going larger.   

I don't disagree, but might wait until you done then look at the duty cycle to verify. Also true fuel pressure affects your output on your injectors, so it could be more or less depending on your pressure. The numbers from the manufacture for an injector are made at a certain fuel pressure, so you need to look at those pressures and make sure they are being measured at the same pressure, if not this needs to be factored in to your choice.

[Midnight Rider]

There are days when Arlo Guthrie just goes wandering through your head.... 

I thought those were K's Don....

[Midnight Rider]

Nidan,

I believe if the builder does it right he will have to look at larger injectors just like Howie ended up doing.   Look at Howies they almost could get away with the stock ones but actually couldnt due to the build and that was 110 not 117 and the numbers were 126/120 while I agree they had a large throttlebody and air cleaner the duty cycle was in Joes opinion too high to not go larger.   In this case depending if lets say they get 10 percent over in numbers that is 128 / 128 for sake of arguement that would put him in the same boat as Howie depending on throttle body.   Until it is actually built and someone can duty cycle the motor / injectors it is going to be a best guess, but personally if I am pushing constant 65-75 percent utilization I am going larger.   

Both guys I'm talking to about a possible build to a 107 are recommending going to the 4.9 injectors.

[Talon]

Agree with Unbalanced, if you get to 75% duty cycle you pushing it, you'll be spraying way to long. Most good tuners that have dealt with a build like your doing, can probably just go by experience. If you getting up there in the hp, like over 125 you might be on the edge.     

[skyhook]

Thanks, guys, that's good info. I'll compare it to what the builder comes up with. He's going to bore the throttle body and port match.  If I were going for maximum hp, I'd spring for a kuryakyn or hpinc.  Really looking more for torque and throttle response.  I've tweaked this 103 a couple times and always been disappointed with the results, so I'm hoping 1/4" more bore will wake her up!