5 bar gate ?

outtacontrolla

Nah only joking .....
anyone know what early bikes used a 5 bar fuel pressure regulator ? Or was it a upgrade for early kit or sp's ?
or which chips are set up for them?
Looking at 851 regulators I can't see any markings , but I have a set of eprom chips 004 to 007 and I seem to remember these were for a 5 bar set up ?
thanks in advance , Steve.

griff851

The early regulators have a removable bung in them that allows you to adjust the the relief pressure. Wind the screw in, get more pressure. What they go up to I have no idea.

freqrider

I think Corsas ran 5 bar. Sp* are 3.5 I believe.

MarkT

Most Street single injector 851s ran 3-bar fuel pressure which is the stock setting for the larger adjustable pressure regulator. Depending on the setup I have seen Corse motors 888-955 have their regulators set between 3-4.5 bar. I need to check my throttle bodies that have black injectors since I have never taken a close look to see what they have been stamped. I have only heard that very early Corse (1988) ran 5 bar regulators. My '89 Works bike runs a 3-bar regulator with green injectors.

jakepeewee

My 851SP3 has an adjustable pressure regulator. When I bought the bike in 1997 it was set at 3 bar which I believe was the stock setting. After some tuning work I ran out of injection time (OEM red injectors only flow like 190ml/min) so I raised the fuel pressure to 3.7 bar.

outtacontrolla

Yea std is 3 bar , but I have a set of early chips 004 to 008 and in that range may be need 5 bar , meaning they won't run well if 5 bar is needed , but it seems 5 bar is mentioned occasionally but with no other reference ie to models or ch no or chip no ....

griff851

Easy then, pump is a standard 5 bar pump. By pass the regulator and block the return line. You’ll soon find out if it floods itself to death and won’t start and give the bores a wash or runs like magic. 😁
But no, you could however buy a variable regulator and slave it into the fuel lines by passing the original regulator. Make sure it’s easily accessible and a little gauge might help. Start the bike at 3 bar and start winding it up. With tape and tie wraps, you could even crank it up and down as you test ride.
Attached pic is FIM HHT Attached for test ride. You soon work out the sweet creamy spot between harsh (lean) and boggy (rich) is.

outtacontrolla

Good idea , I have adjustable regulators in stock !