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[GRock]

Originally Posted by Griffiss

Well I see a Gerolomy in my very near future, I finally found the bug I have been chasing all summer, the throttle rod in the stock Delphi was cracked now broken. Not gonna buy another Delphi, I have decided on the Gerolomy, now the question is do I increase the injectors to 6.1 and whose, or do I stick with the 4.89 that came in the SE Deuce. A little help please, Rock? S&S 585g and some head work on SE heads, SE pistons, compression slightly over 10.5 to one.

4.89's are perfect for your set up, no need to go with larger. And with the dual runner you will add a higher ceiling to your potential HP, so no worries in that department. Smoother idle and sharper low end and accel with the 4.89's as opposed to the 6.1's. As with a lot of things on strong street bikes, larger is usually not better.

Now for all of you injection junkies, please hear this......
General rule for injector flow rate is to go with lowest flow that will handle your top end and still give you good low speed and idle characteristics. The problem with injectors is that just a small problem with uneven flow or a slight restriction will cost you big time power and raise havoc with tuning. Especially with a lot of bikes that are just driven occcasionally or are seasonal. It doesn't take much for these things to gum up as most fuels now have ethanol in them and this evaporates rather quickly and leaves the heavier compounds behind which can cause problems in engines that are not used every day or are stored. There are many companies that speciallize in blueprinting and flowing injectors and the service is fairly inexpensive. We use a company here in CT for all our racing engines (marine and cycle) that does real inexpensive work on every day injection also. You'd be surprised at the difference you can get from having balanced and equal flow injectors on a bike that had tuning troubles.

A certain cycle company was having troubles with the "stock" injectors and they were blaming poor perfromance on the spray pattern of the injectors. Bullshit!! The injectors were not flowing equally in many cases and were not matched. So the mantra was to trade them out for a different spray pattern. It wasn't the pattern it was a combo between balanced fuel delivery and a higher flow rate that that matched up better with the fuel mapping and the result was better idle, smoother performance and cooler running.

OK, now my hands are tired!!!

All the best.

G