Factory Pro needle jets

[steamer97]

Greetings all,
I was reading the Factory pro site and viewing the pictures of worn needle jets and their pics show their jet as oblong and stick as round. I assume this is a mistake. But a question remains in my mind about whether or not I need new jets. I looked at a dozen needle jets in my stock and all look concentric.The seat is so small its hard to be sure and since its recessed my measuring tools wont decide if they are oblong or not either. Has anyone replaced these jets and actually experienced a benefit? At almost 150.00 with shipping I won't be ordering them just for fun. I have a set of old, crusty jets and after cleaning the crud off of them, I didn't notice wear. I used magnifier lenses and bright light too. I understand how the engines vacuum draw may wear the brass jet on the engine side if you have other than aluminum needles causing a rich condition that may not be correctable. feedback on this subject will be appreciated.

 

[one2dmax]

They have had that info up for years and I thought the same thing for awhile. But, we've not replaced very many for excess wear over the years. I suppose if a guy has tried everything for tune issues and poor mileage this might be worth trying.

 

[caseyjones955]

When I was working through my 89 Venture V4 I tried many things to get the MPG up from 30. Ignitek, COPs, new diaphragms, floats adjusted, brakes converted to R6 to eliminate the binding factory pinchers. On and on. It was running amazing too, no matter what, 29 MPG. I installed a set of drop shims which moves the needles about a half clip (IIRC) inward beyond normal adjustability. Bang! 40 MPG, ran the same or maybe better. I enterpreted that as an indicator that the emulsion tubes/needle jets were oblonged with 75k mi on the clock. Most Venture guys report around 40 stock so it got me up to normal-ish. Well, the bike anyway. It actually runs pretty darn well for a morbidly obese, detuned touring version of a Vmax. I know the Vmax is really a Harley slaying version of a Venture. Either way I have one of each and love em' both.

Rather than replacing the needle jets I left the drop shims in and just ride the shit out of her as is. If needle jets are not my issue then Im at a loss for what it might be. That being said I have scarcely heard of it being an issue.

 

[one2dmax]

Drop shim?

 

[caseyjones955]

Drop shim?

Its a shim set that replaces the white nylon collars that slide up the needles against the clips rather than going between the collar and clip to lift the needle further out, this shim is a needle clip (or so) thinner than said OEM white collar. It enabled me to move the needle further in than I otherwise could using only the OEM bits. It is my understanding that engine vacuum can draw excessive fuel around a fully seated needle causing a rich condition even before the needles begin to lift at around 4k rpm. I thought this would compensate and show me if the issue was related to needles and tubes. Btw I too had the emulsion tubes under light and magnification and could detect no visible wear, but it is hard to tell for sure.



As I was going through everything to sort the MPG issue someone on the Venture forum mentioned a member that sells them (along with brake delink kits and other cool stuff). I decided to try it as a diagnostic move and there was the lost 10 mpg. I figured that meant the emulsion tubes were worn and I could replace them, maybe find some needles with more adjustability, OR I could just embark on a four state ride. unk:.


They look like cheapie hardware store washers that maybe cost almost nothing but its worth $10 to have the right sizeed ones to my door and avoid fighting traffic in town. Sorry about the windy response but I know you forgot more about these engines than I ever knew, so I'm interested in anything you may have to say about the issue, or the band-aid it currently wears.

 

[one2dmax]

That's a very intersting observation and something worth note! If you get a chance you might email me with more details and a link to them. Might be worth seeing if I can make something like that or add his contact.