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Fuel pressure regulator change

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Hi

A Finnish Super Blackbird driver linked a discussion to an XX forum's discussion on aftermarket fuel pressure regulators. There seems to be lots of positive feedback regarding this tweak. Has anyone tried this in a X11? The topic says that older XX's can use the fpr from a newer Blackbird, I wonder which part would be the best for X11?

Topic 1 and

Topic 2

To be honest, I did not have time to read through all the discussions, just took a quick peak. Still would love to hear your thoughts on this?

Regards

Topi

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Sounds interesting and something to think about. Looks like all the X's use the same FPR that the early Blackbird's used.

If anything, I'd think about trying the later model Blackbird FPR (£27 from Dave silver spares) rather than going for the expensive yank item.

Anyone ever have cause to check the fuel pressure on the X, if so what pressure did you see (43 psi would backup the theory).

Thoughts anyone?

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This sounds like a simple mod - have to check it out. Damn! More stuff to think about! I just want it back on the road...

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Sounds interesting but the thing that slightly worries me is the comment by one of the posters...

Quote.."I think it adds a bit more fuel. My exhaust went from a light tan to a dark tan".

This sounds like the exhaust pipes are getting too hot, and if they are getting too hot, what about the engine temp?? :unsure:

Think i'd leave mine well alone.

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Sounds interesting but the thing that slightly worries me is the comment by one of the posters...

Quote.."I think it adds a bit more fuel. My exhaust went from a light tan to a dark tan".

This sounds like the exhaust pipes are getting too hot, and if they are getting too hot, what about the engine temp?? :unsure:

Think i'd leave mine well alone.

I haven't got in depth knowledge about X11 fuel injection system but based on the little that I know about similar systems in cars I would think that this is what happens: on any given moment the ECU calculates the amount of air that goes into the engine on current RPM and adjusts the opening time of fuel injectors based on that. Fuel injectors themselves do not regulate the amount of fuel injected, only opening time. Therefore, with higher fuel pressure in fuel line the amount of injected fuel would be greater than that with a lower fuel pressure, since more fuel is squeezed through the injector in the same time when higher pressure is applied.

The benefit of this would be based on richer fuel - air ratio on partial loads. This assumption is based on manufacturers goal to compromise between performance and pollution or mpg ratings. This mod would therefore make the bike run better by sacrificing some of the pollution and mpg ratings, thus giving better overall performance. Higher fuel to air ratio on partial loads would actually not make the engine run warmer, but cooler. Why that one bloke's exhaust changed color I do not know, but if the mixture is too rich then it will not all burn in the engine and the remaining fuel will burn in the hot exhaust.

That's the only thing I can think that this is based on. It's not magic, that's for sure pirate.png

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Sounds like this could be a simple mod. I'd be most interested if anyone wants to have a go at doing it, I reckon this could be an earner for someone with some skills!

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I have had cause to check my fuel pressure and found that after 10 years of running the fuel pressure was 28 psi at the rail, the fuel filter was replaced and the pressure increased to nearer 40 psi.Even at the lower pressure pre filter change i never experienced any running issues. The injectors will also play a small part in fuel pressure, if they are partially blocked they will have a bearing on the fuel pressure. The manual gives a fuel pressure but also a flow rate, the flow rate is just as important because the pump will deliver a fixed volume (flow) of fuel and if the filter is fouled the flow will drop, the pressure regulator is responsible for pressurising the flow and it would be harder to pressurise a lesser volume of fuel. The idea of replacing the pressure regulator would make some sense but also ensuring the injectors were not fouled would be worthwhile at the same time, these can be cleaned professionally by return post for around £12 each + vat the benefit of having them done in this way is that all the seals will be replaced and the injector filter will either be cleaned or replaced.

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I have had cause to check my fuel pressure and found that after 10 years of running the fuel pressure was 28 psi at the rail, the fuel filter was replaced and the pressure increased to nearer 40 psi.Even at the lower pressure pre filter change i never experienced any running issues. The injectors will also play a small part in fuel pressure, if they are partially blocked they will have a bearing on the fuel pressure. The manual gives a fuel pressure but also a flow rate, the flow rate is just as important because the pump will deliver a fixed volume (flow) of fuel and if the filter is fouled the flow will drop, the pressure regulator is responsible for pressurising the flow and it would be harder to pressurise a lesser volume of fuel. The idea of replacing the pressure regulator would make some sense but also ensuring the injectors were not fouled would be worthwhile at the same time, these can be cleaned professionally by return post for around £12 each + vat the benefit of having them done in this way is that all the seals will be replaced and the injector filter will either be cleaned or replaced.

Thanks for your input. I've played around with car fuel injectors and based on my experience on those, I do not think my 36000km with Finnish fuel (extremely high grade, high octain and very pure compared to what's commonly available in Europe) have done any damage or blocked the injectors. I'm planning to change the regulator only, do visual checks to other parts at the same time and change the fuel filter since it's a cheap and easy thing to do at the same time.

The manual says fuel pressure is 43psi and the new regulator should increase it to 50. I do not have the tools to check these figures and as I'm planning to do all the work my self I'm not going to bother to take the bike to a shop just to get that done. A bit of flying blind so it's going to be trial and error and measured with the famous gut feeling :P I'll let you know first impressions when the job is done.

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I may measure that fuel pressure when i have time to pay attention to my bike again.

Hmm, what if, the pressure is low, and for example i change the regulator, then the "map" (dynojet) what was done last spring isnt "valid" anymore. Maybe they have noticed something when they drove it on dyno?

Anyway, i will look on that pressure issue when i have time.

I think that normally that O2 sensor "tells" how much fuel is injected, and when the pressure is raised, the open time of injectors is shorter due that more fuel is getting in the cylinders. Benefit may be, that when the fuel is injected faster and with higher pressure, the "fuel mist" is finer and burning of that air/fuel mixture is much better.

When using O2 sensor eliminator with DynoJet, like me, the mixture is getting richer, maybe too much, and the system needs "re mapping".

With my Dynojet LCD display, i can see injectors "duty"/cycle, it tells how much is the opening time/ cycle, seems that i dont have to worry, common info is that when the value of that "duty" is higher than, lets say 80%, then there is need for bigger injectors.

Lets see....

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Job done! Takes 15 minutes if tank is drained, 30 minutes if not. Mine wasn't.

I ended up spilling quite a lot of the fuel so I only took the bike for a two minute test drive to make sure it still works since I did not want the exhaust pipes warm enough to light up the spilled fuel :rolleyes: Impossible to tell about the benefits yet, but I'll report back when I have time to take her out on a longer ride.

The whole thing cost me 45 euros.

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Job done! Takes 15 minutes if tank is drained, 30 minutes if not. Mine wasn't.

I ended up spilling quite a lot of the fuel so I only took the bike for a two minute test drive to make sure it still works since I did not want the exhaust pipes warm enough to light up the spilled fuel :rolleyes: Impossible to tell about the benefits yet, but I'll report back when I have time to take her out on a longer ride.

The whole thing cost me 45 euros.

I've now driven about 180km (110 miles) after the mod. The biggest difference seems to be that the motor runs better cold than before and it does not stall in corners even if I don't pull out the knob that increases revs (no dictionary here but you know what I mean).

Another thing is that I've not noticed the surging on 3-4000rpm. The rest of the benefits that the Blackbird owner reported I can not agree with. I can not say anything about mileage yet, except that it has not decreased dramatically because I already have 210km on the clock since filling her up the last time and no fuel warning light yet. I get it quite punctually at 250, at least did before the mod.

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So are you saying you no longer have the surging at 3-4000 rpm?

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So are you saying you no longer have the surging at 3-4000 rpm?

You are correct. I've never really felt that this would be a big problem anyways, but during the above mentioned "test miles" I did not pick up those vibrations. I can pay closer attention to this while riding during the next week or so and report back.

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Seem a worthwile job to do then if it gets rid of the surge. ;) Mine does it all the time.

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Interesting and I'd like to hear how th emileage (petrol useage) turns out. If there's a big dif, I'd be tempted to keep mine the way it is. However, a quick and cheap add-on sounds like a possible winner to beat the surge.

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My concern would be that there is a possibility that the fuel pump may be subjected to back pressure forcing it to work harder as the regulator builds a higher pressure in the manifold, i dont think the blackbird uses the same fuel pump as the X11, if someone could confirm that the pumps are the same then it looks like a good mod.

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My concern would be that there is a possibility that the fuel pump may be subjected to back pressure forcing it to work harder as the regulator builds a higher pressure in the manifold, i dont think the blackbird uses the same fuel pump as the X11, if someone could confirm that the pumps are the same then it looks like a good mod.

That's a good point. My only experience from the vulnerability of fuel pumps is from some BMW's (cars) that use fuel to cool down the pump. There are cases where break downs have been caused by constantly running with the tank almost empty so that the pump is not covered by fuel and therefore running very warm. I know some cars that have this same mod without problems with the fuel pump. The unit is naturally not the same so I don't know if the example applies here.

235km now on the clock and no fuel warning light, closing on the "standard" 250km...

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235km now on the clock and no fuel warning light, closing on the "standard" 250km...

Fuel warning light came up at 240km. Not a significant difference to my standard, but keep in mind that this is only based on 200+km riding.

I'll report back with more km (miles) on the clock, but so far I'm not too impressed about this mod.

Edited by Sickness

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Ok if you do a google search for the honda X11 fuel pump part no 16730-MAT-D00, several sites pop up with reference to 99-2002 blackbird fuel pumps , one of them being cheepcycleparts.com an american site but good for reference as they show all the microfiches , unfortunately not the x11 because it never got sold there.

The actual fuel pump within the assy looks just the same as the blackbird one so the , wemoto replacement pump may be an option.

John

http://www.cheapcycleparts.com/model_years/1055-honda-2002-CBR1100XX/assemblies/13297

Edited by x11r

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The fuel pump sub assemblies are the same part number for both X11 models and all Blackbirds up to year 2000. It's even the same number for the early carbed models. The part number (for reference) is :-16730-MAT-D00. The sub assembly is the actual pump, but various ancillary fittings surrounding the pump are not the same. Hope this helps......Steve

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I know this is an old subject , but I am having running problems missing at 2000-3000 rpm clears once opened up ,only mod is after market exhaust and k&n air filter ordered a fuel filter and the regulator will see if this improves after fitting .   

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11 hours ago, Farmerphil said:

I know this is an old subject , but I am having running problems missing at 2000-3000 rpm clears once opened up ,only mod is after market exhaust and k&n air filter ordered a fuel filter and the regulator will see if this improves after fitting .   

Don't know if this will help, did it start missing when you fitted the can & filter,  I had a blackbird which I put an Akrapovic system  and K&N filter on and had it set up on a dyno. I ran it with just the Akrapovic on for a couple of weeks and it was fine, on the day it was getting dyno'd  I fitted the K&N and that really messed things up, but once the fueling was set up  it was a big improvement over stock. if it only started missing  after you fitted the can & filter I'd try running with the standard filter back on. I suppose you've checked the little things like loose connectors and plugs, I've had expensive iridium plugs brake down at low revs but work ok at higher rpm even after very low mileage. Hope you get it sorted

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Thanks for the info ,it was not right before I fitted the cans the filter was already on the bike when I bought it I think that with the age of the bike and also the lack of history it is prudent to change both the filter and regulator ,if this does not rectify the problem I will look at the plugs 

 

 

 

 

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Mine was having the same problem, 2000-3000rpm lack of strenght, and it seemed like it has a turbo after 3000rpm. Just changed the fuel pressure assy. and it is smooth as new.

I decided for a standard Honda part because it gives more MPG.

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