Well here's the story so far, I fitted the new float needles, float seats and also the new mixture screws and o-rings. I reset the mixture to 5 quarter turns and the float heights came in at 9.28mm. Blasted everything through with carb cleaner and compressed air. Done an oil change with some halfords oil - with a view to running it up and changing it and the filter when it's on the rolling road. I bought a fuel pressure regulator which I got from McGills motorsport ebay shop, one of the rotary ones with the dial, fitted it and also fitted an inline fuel pressure tester gauge. With fuel tap fully open the pump running but bike not running the pressure was showing as 2 psi. I ran the bike up and it didn't really change. I ran it to Steve Jordan Motorcycles this morning and I have to say she felt like she had more 'bark' and crispness. It behaved for the whole 20 mile journey, and when I got there it didn't shart it's tank all over the floor. So, hopefully she'll have a long overdue setup on a dyno and all will be good. So we wait and see.
That's a good result Sev. It would be really useful if you could post up a pic or two of the final set up.
Sure thing mcr, the pressure regulator and the pressure dial were a bit heath robinsoned on, and, after the comments above I was in truth surprised to see just 2 psi (and that's without regulator attached) reading on the dial. As it is, I'm taken with AL's facet pump so perhaps over crimble I'll go that route. I've promised myself a new loom so perhaps I'll integrate it into the design of that. When I get it back I'll get the full low down from Steve and i'll post it up with some pics. Just a pity I'm not there to see the thing on the road really as I'd love to get some video of it for y'all.
I got the idea of the Facet pump from Ghost (Phil), 'cos he had it on his race bike...........and Phil wins, so it must be OK. However I did a lot of research to establish which pump, mounting position etc etc; with a view to incorporating a proper reserve tap in the tank, doing away with the fuel level float. AL
I still have that pump and it kept overwhelming my fcr's and pumping fuel over closed throttle which made for an interesting test run.
That's 'cos either you have the wrong pump rating (should be 1-4) or no return in the fuel hose layout..........and/or faulty float valves. However, one thing I never checked with the pump, because I was going to address it when fitted.......When the pump is mounted in accordance with the manufacturer's instructions, there will be a 'head' of fuel above the pump which gradually reduces as the fuel level goes down. If the pump is 'open' when it isn't running, I can see that the 'head' of say 15 litres of fuel could possibly push the float valves open and dump a tank full into the engine and out the overflows (the overflows aren't large enough to drain the excess quickly). Therefore if this is the case, then an electronic valve of some sort is needed between the tank and the pump to cut off the head of pressure when the pump is still. Obvioulsy the way to tell if the 'head' will be a problem, is to disconnect the feed from the pupm to the carbs and see if fuel runs out of the pump outlet when it isn't running. AL
Quite a long quote but, i can see a head of 15 litres opening the float valves if it were say 2m above the carbs but in an instance on a bike i have to dissagree unless of course as already stated the float needles/seats are worn or the wrong size of seat is fitted. i would say its a faulty seat. even if its brand new something is wrong. i do agree with having the correct rating pump, over 5 psi will open the valves but will only give a higher fuel level until the float suts off the fuel with the extra pressure the higher level has achieved. I think al would agree with me here that you need to recheck everything before fitting any pump then select the correct pump rating for the float seats that you have.
Mikuni BDST 38 carb new float valves appear to be forced open at roughly 12-15 psi.............a full tank giving a 'head' there is on the SS would not be enough to force them open IMO........as to what it would take for the FCRs to open, I don't have a clue........... ............however, I would look at the Facet pump to see if fuel can run through it under gravity while it is not working.........IE, is there a shut-off diaphragm / valve thingy inside? AL
It has been a few years since i dealt with any facet pump (20ish) but on the older ones there was just two sprung diaphragm valves both acting as one way to pump the fuel, if there were enough "head" as you say it would just run straight through. The mitsubishi one from the early r1 is the same hovever you can alter the spring pressure by substituting differing springs to alter the pressure. i did not bother as it came from a carbed bike anyway so felt there was not going to be a problem.
I'm not sure how the FAcet solid state pump actually works......................but I do know they are noisy, but on a Ducati, who cares?
So finally got it back. He changed the main jet to a 150 and set the float height to 12mm. I haven't checked what the mixture screw was set at but one thing is certain compared to what it was like before it pulls like a train and also there is a noticeably different bark to the exhaust not, its so much more crisp and sharp. The mission now is to make the spaghetti system sit level as one of the end cans is currently on the piss and sits higher than the other. I t doesn't help that the carbon hangers were made by stevie Wonder whilst on holiday in italy - they're proper shite, and not even trimmed up evenly! A real joke, but somehow I don't think that I'll be able to get hold of the stainless hangers that the pipes also came with back in the day.
These are great results, looks like he found you an extra 5hp! Just remind me, are you on 39's or 41's, also what was your float measurement before he set it to 12mm?
You did Al spike, I had them set to 9mm, they came out to 9.28mm and I didn't want to mess with it anymore as they were both equal. I set the mixture to 5 quarter turns, but he didn't mention having fiddled with that in his notes and I'm not about to mess with them to see.
Just got a follow up call from them to see if all was OK, and I took the opportunity to ask the question. He had the carbs at a 45 degree angle and measured from the carb body to the top (furthest point) of the float. giving a reading of 12mm. Spike, they are 41's.
