I have an 07 EG which came with the 96" engine and 27709-06a fuel injectors which are rated at 3.9gr/sec. I see that the 08's and up 96ers, and then the later 103's came with the 27609-01b fuel injectors which are rated at 4.3gr/sec. Since I have upgraded to a 103 and SE204 cams I'm wondering if it would be worth my while to upgrade my injectors to the 4.3's, basically they would flow 10% more fuel.

Whats confusing me is the 05 and down bikes with the 88's show 27609-01 and 01A injectors as stock which flow more?, the 08's and up with 27609-01b as stock which flow more, with only the 06 88" and 07 96" running the 3.9's?

any idea why?

EDIT: I forget which year they went from 8 degree to 25 degree injectors, I'm thinking it was 2006, which would explain the different part number in 06 and 07. The switch to the pre 06 injector, 27609-01 but with a "
b" suffix, would be it was higher flow but with the 25 degree nozzle?

Jim

 

100hp is about it for the 3.9s.

The 8 and 25 degrees flowed the same but due to the different spray patterns, there was a very slight difference in how the fuel was processed and this shows up as a slight difference in the VE tables. The 8 degree injectors had problems with stalling at slow speeds, especially very light throttle on turns.

The injectors previous to 06 and the injectors on the ETC throttle bodies have different connectors - you can only upgrade with injectors specific to the manifold/wiring you have. Off the top of my head I believe you need the 4.9 gs part number 27797-07

 

In my post above I mean that the injectors previous to 06 and the ones in the ETC have different connectors than the 06-07 cable operated throttle bodies.

 

injectors can be compared to carbs in a way.
a 400cuft and a 450cuft could be illustrated by 3.9gr/sec and a 4.9gr/sec
how???
well both are a full load ratings
sure one can deliver more than the other if it is called for and most importantly if the engine can actually make use of it.
at part throttle, the plate restricts flow and fuel delivery
at part throttle the injector on time restricts fuel delivery in relation to calculated air
throwing a larger carb than needed can cause issues
although a larger injector would have shorter on times than a smaller one, there could be map issues as far as the numbers go but would be tolerated more so that the carb changes. most for longevity strive for a 50/50 duty cycle. the longer the on time, increased chances heat issues with the injector and driver.
whole point being is to match the potential of the engine which is probably what hd has done.

 

Same engine, 96, but 3.9 in 07 and 4.3 in 08, wonder why? In Ed's reply it sounds like the 08 and up 4.3's won't work in 06 and 07's because of different connectors.

 

i ride gravity, never fails.
most of my injection history comes from auto and commercial engines
as far as connections, that is a no brainer if you wanted to swap them. the biggest issue is the coil, it has to match the driver or you can have issues. did hd change things up in the ecu??? if so then they match the impedance of the coil to match the driver, do not know. now that being said, does it show up in the parts fiche?? well maybe and then maybe not. sometimes things are backwards compatible so a parts number would not change. i can not answer that.
one would have to look at the injector spec to see if they are electrically compliant.
hd probably does not have that info but they do not make the injector so find the mfg and find the spec's.

 

The injector you would install would be 27797-07 4.9 g/s. It is a direct bolt in for your year and throttle body. It would require (at the very least) adjusting the injector flow rate but will really need the tune verified on a dyno. The 3.8s tail bite at 6000 rpm and are in the 90% duty cycle range at the high load high RPMs. (At 6,000 rpm it takes 20ms for the engine to complete the OTTO cycle)