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Wow - that was a fast reply - Thanks a million! However - yesterday I managed to massage everything into place, but it refused to start :-( Taking a break today to give my poor hands a chance to heal- abrasions and little wounds abound after the sessions. I haven't even checked if it's a fuel problem or electrical
Looks like it is leaking gas from the intake line as well, so probably I will have to dismantle the whole thing again. Well - no sweat - now I know how it's done. The weather is no-go anyway, so I'm taking it really easy.
I'll keep y'all updated - I even have a dyno run scheduled. As it was it gave 61.5 hp with Jetkit and KN-filter, open pipes (well sort of), so it'll be interesting to see the new figures.
 

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To reactivate this thread, I have 41's on the short Malossi intakes and am ditching my fuel pump. I am replacing all the lines and am adding a fuel filter outisde the tank, as well.

In order to not have to remove the fuel line when lifting the tank, the line takes a bit of a long route with a couple of dips and rises in it.

Should I be paranoid about the routing of the fuel lines to insure good fuel flow or, assuming no bubbles in the line, will the line naturally tend to flow due to pressure from the weight of the gas in the tank and siphon effect below?

Thanks for any updates anyone has.

Oh, I have had my bike for many years. It has V2 cam, knifedge crank, ported heads, 12.5 pistons, etc. etc. and the previous poster was right about improvement above 7500. I don't turn it above 9000 since I rebuilt it, but before, it was making HARD power to ten grand. With long intakes, there is really nobody home above 7500 or so and no real reason to keep reving the bike. With the short intakes, it is a WHOLE different animal.
 

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Discussion Starter #23
Well done ApexDC, I did indeed install my 41 FCR's - OMG EIGHT YEARS AGO!!!

Time always flies... I didnt have any short inlets so just mounted the twins and after having to remove again due to petrol flooding, new seats made the job a good 'un and I really enjoyed the difference but you get used to the addiction too soon, of course.

My poor SS has sat for 5 years now with a cracked frame :crying:

I even bought a set of split singles from this forum and imported them to the UK, the seller had cleverly obtained a spare set of OEM inlets and cut them down to copy the Malossi stubs.

They likewise are sitting in my garage.

Its all pretty sad really.
 

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Yes you can junk the fuel pump

So I have just finished a rebuild of a 1993 900SS and managed to find a pair of 41mm Keihins. They are stock standard according to the CA Cycleworks settings and fitted straight onto the stock manifolds. I have gone for pod filters and left the remainder of the battery box to keep the battery and coils mounted in the same place. The first thing I discovered is that they will quite happily drain the fuel tank and fill the engine sump up to the vertical cylinder head with fuel! Apparently this is normal and looks like everyone with FCR carbs does this once before fitting an in-line petcock.

The bike ran OK with the fuel pump but I didn't think it was as clean as it should be, occasionally on a steady throttle setting it would "sneeze", very strange and kinda felt like over-fuelling. I have read on here that FCR carbs don't like to be force fed so elected to remove the fuel pump. I removed the pump and filter and ran it for a few days with a full tank of gas so that it would gravity feed. Much improved IMO and the sneezing was cured. I then got brave and cut the fuel feed pipe inside the tank off at the base so that all the fuel in the tank is available. The tank is now permanently a gravity feed system and there is no reverting back to a pump! I have installed an in-line fuel filter upstream of the in-line petcock and left the tap on the bottom of the tank open.

The feed from the bottom of the tank is well above the inlet to the carbs so the fuel will feed all the way to empty. If anyone says you must have split carbs to achieve this they are misinformed, go and crouch next to your bike you can see the inlet to the carbs is well below the bottom of the tank (or the point at which fuel leaves the tank - in my case the cut pipe). Don't worry about any dips or corners in the fuel feed hose, as long as there is fuel above the curve or dip gravity pressure will overcome this and fuel will flow (the fuel line runs pretty straight anyway from the tank to the carbs, if you have major kinks or bends you have routed it the wrong way).

Another comment I have seen is regarding the need for larger float valves to allow enough fuel to flow without a fuel pump. Not my experience so far but then I am riding the bike at sane speeds and do not have the testicular growth to hold the throttle wide open for any length of time. If you were racing this may be the case but for normal everyday riding I have not seen any fuel starvation problems (and I have given it plenty of handfuls to make sure). I can only assume the carbs have standard float valves fitted as supplied by CA Cycleworks. (My thoughts on this anyway are: if I wanted to drain the fuel tank in the shop to remove it I would turn the tap on and poke the fuel line into a canister and watch the fuel drain out. The bike tank would empty in about 10 minutes. I would have to be riding pretty damn hard to drain the fuel tank in 10 minutes so I think there is plenty enough fuel flowing).

Anyways, my thoughts on fitting and setting up FCR carbs. Ooohh baby you cant beat the improvement in horsepower but the best fun is the induction noise. Never gets old and might explain the poor fuel economy...
 

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...The first thing I discovered is that they will quite happily drain the fuel tank and fill the engine sump up to the vertical cylinder head with fuel! Apparently this is normal and looks like everyone with FCR carbs does this once before fitting an in-line petcock.
...
I wouldn't say that this is normal at all. Some do install petcocks to protect against this inadvertently happening (I haven't), but it's definitely not normal.

Best of luck with the tuning. FCRs are a fun upgrade.
 

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I discovered something about FCR's this weekend gone - you can remove the float bowl (and jets) with the carbs in place (well, the vertical cylinder carb at least). I had an engine failure - just after filling the tank - I did just enough distance for the 'new' gas to hit the carbs - and it cut out on one cylinder. Luckily, I was still close enough to home to turn around and limp back.

Pulled the plugs, and both electrodes were chalky white. "It must be fuel related" I think - "I'll try draining the bowls". Nope. Nothing obvious. Next step - drain the tank, and put in some gas from a 20 litre container I have at home. Nope, still only one cylinder. Pulling the plug leads proved it to the vertical cylinder - so after inspecting what I could (good spark on both cylinders), I managed to undo and drop the float bowl, then pull all the jets. Nope - all clean. :confused: This was starting to bug me. Put carb back together, try it - still only running on one. Go have a cuppa.

Come back, pull airbox lid, do visual check - gas flowing from accel pumps OK. I'll try firing it up. Hmmm - something doesn't sound right on the intake side - carb on one side makes different sounds to the other. Pull plugs - do compression test. 125 psi on horizontal pot, 80 psi on vert. :( OK - something serious here. Decide to check cam belts - oh BUGGER! One had snapped - one of the tensioner rollers (bearings) had seized totally, and the belt had shredded (literally) itself. However, the Ducati mechanical gods must have been smiling on me, as no valves bent, and with new tensioner bearings, and some old belts (kept for an 'emergency'), it tested fine for compression on both pots, and fired back up sweetly. :D Now just got to get the new belts and replace ALL the rollers and tensioner bearings.
 

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The first thing I discovered is that they will quite happily drain the fuel tank and fill the engine sump up to the vertical cylinder head with fuel! Apparently this is normal and looks like everyone with FCR carbs does this once before fitting an in-line petcock.
No, this is NOT normal.

This happens when there is crap blocking the needle valve.

Tom
 

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The first thing I discovered is that they will quite happily drain the fuel tank and fill the engine sump up to the vertical cylinder head with fuel! Apparently this is normal and looks like everyone with FCR carbs does this once before fitting an in-line petcock.
I haven't had this happen but because many say it is a possibility and I didn't want to take a chance, I fitted an electric fuel cut-off valve which is wired in with the electric fuel pump (pumps a 'loop' from tank, back to tank with a 'T' to the carbs). This way I don't forget to close a manual petcock, plus I can remove the fuse to allow me to run the carbs dry if required and the valve has a manual override in case the solenoid should fail so that I don't get stranded.

I also fitted a TPS to one of the carbs which feeds into the Ignitech ignition module and really makes the power delivery more user friendly.

As for filters I got some K&N stacks (designed for FCRs) which then take K&N filters.
 
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