Fuelling and pressure query

och2pot

.040 Over
Joined
Feb 28, 2010
Messages
93
Location
Scotland
Hi all

Anyone know about the fuel pressure regulator on the R3? When I had my 955 Sprint, I found a post on a forum about (thanks to whoever it was) .....the cheapest and most far ranging mod to up the fuel pressure from the stock regulator setting of 40 psi to 60 or more. (set at 3 bar on the R3, 42psi)

It doesn't change anything but provides for a bit more richer mix throughout the entire mapping range which is what Sprints apparently needed as they are mapped lean. He also believed that it provided a better spray pattern from the injectors.

This is easily done by modifying the existing fuel pressure regulator by squeezing the steel case a bit in a vice to increase the spring pre-load. I never got round to trying it before my Sprint was written off in a smash.

Just wondered if this could be done with a Rocket? I haven't been able to see the regulator well enough in the manual.

thanks
 

dent one side for 5 psi both sides for 10? Sounds like you need to start drinking single malt instead of that cheap stuff.
 
Aye Stripes gie the bl**dy thing a wee squeeze tae sort it oot and squirt a bit harder - as the actress said to the bishop......
Hoono if itgies ye abittiemairwheech... Talisker does the trick

2294cc = 3 bottles of the best by the way plus a dram
 
The theory is correct. Turbo Tom in Orange County ,CA makes a new regulator with upped pressures for the Honda St1300's. It works. With more pressure more fuel sprays during the time the injector is open. Is it better than a fueler? No, but if you can figure out how to adjust it it's worth a try. Smashing the spring housing in a vice is a bit "Un-scientific," but if you can make it work great!
 
I ust'a have a Hardley I would beat on every now and then when it wouldn't start. Never worked but it made me feel better. See pic of me towing my Hardley to the shop in my gallery.
 
Epicycle Australia Epicycle Racing - Fuel hardware have a fuel pressure regulator "varireg" with a universal barb fitting that may be useful, but probably would be a pain in the freckle to adjust. The Sprint ST 955 was easy as the regulator was external on the tank, The rocket regulator is inside the tank . I haven't dismantled a rocket fuel tank so I don't know if it would fit. Hope this helps.
Regards,
Duncan
 
The fuel pressure mod did work very well on the Sprint, but be careful .Time and patience is the key when adjusting the spring tension,
Regards,
Duncan
 
thanks for the link albatross, I'll dig around a bit more about this and see what the rocket's system is really like. That variable pressure unit certainly is a bit more accurate than trial and error! It would seem likely that Triumph use a similar unit on all their triples so what worked on the Sprint might work on the rocket too.
 
Crushing the R3 fuel pressure regulator does indeed work to increase the fuel pressure. But you need to work in small steps. it only takes roughly .020 inches of crush to get to 58 psi/ 4 bar. This give a roughly 16% increase in fueling. The problem is that this is a global change - across the entire operating range. In order to get good fueling at idle and low loads, you will then be forced to reduce opening times, and this causes lag time (the amount of time it takes a specific injector to come fully open) to become a larger percentage of total open time. This can really screw with low rpm/load fueling.

You need to actually test fuel pressure, not just make blind changes. Even battery and charging system voltage can cause idle fuel pressure to be reduced. 1 psi at idle can actually be as much as a 12% change in actual flow rate.

I hope this helps,

-Wayne
 
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