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Motorcycle carbs on a B21

Nice, I've always wanted to know how a budget (not expensive Evo red-engine) redblock would work out. Still have a very nice bank of R1 carbs on the shelve for this very application!
 
Hotdoggin said:
Right but what happens to the return line already there? Unused? One of those won't completely drown the floats?
Click to expand...

Here is a better picture. I had the lines mixed up, (bottom port on fpr is return) but you get the idea.
k4PwJgrl.jpg


Bad news, I'm going to have to get a low pressure fuel pump and wire that in. The FPR cannot handle lowering the EFI fuel pressures to the carb levels like I hoped:oops:
 
ncbrock said:
Here is a better picture. I had the lines mixed up, (bottom port on fpr is return) but you get the idea.

Bad news, I'm going to have to get a low pressure fuel pump and wire that in. The FPR cannot handle lowering the EFI fuel pressures to the carb levels like I hoped:oops:
Click to expand...

the KJet main pump flows too much at low pressure but the small in tank pump by it's self might work.
 
Would this 76' have an intank pump? According to greenbooks I should just have one outside pump. I have the configuration on the top right picture
84ci58.jpg
 
I thought all of them in the US had two pumps. :e-shrug:
If yours doesn't have the in tank pump, then you have to do like you're planning to do.

I've used those $45 Mr Gasket fuel pumps on a couple different machines and trucks.
 
The early cars didn't come with an in tank pump. There was an updated sending unit for the early fuel tanks that retro fit an intake pump, which is what is being shown in the page you posted.

If your tank has the pickup on the side of the tank, you don't have the updated sender/pump assembly. If there's a plug in the side of the tank and the inlet hose on the pump make a "U" bend and goes up to the top of the tank, you have the updated sender/pump assembly.

240UpdateSender1235227.jpg
 
gashog said:
the KJet main pump flows too much at low pressure but the small in tank pump by it's self might work.
Click to expand...
there were two in-tank pumps used on the later cars, the early VDO intank put out ~3-4 psi, and the later Delco put out 5-6 psi. Carbs like the lower pressures 3psi, so use the early pump, no need to put it in the tank either.
If you want to use a return, look at the '71-72 Volvo B20B with HIF6 SU carbs, that used the fuel return line. The tank has a return port at the back top pass side, but you could use any early 240 top mounted sender w/return port also. The early carb'd Volvos used a Pierburg mechanical pump, which may also be a solution on your pump, as IIRC the early B21's have the side port and a cam lobe on the aux shaft to drive the mechanical pump.
 
I put a Mr Gasket 3psi fuel pump on the car. Everything is hooked up and "should" start. I tried starting it for a minute or so but my battery was dead. I will have to start troubleshooting issues
tEQiJoSl.jpg
 
Are those carbs of dubious origin? Did you pop the bowls to see if they're clean inside? My car runs on a single 45 jet for the idle jet. You'll probably have to put a couple pumps in. Pull the choke with your hand, and have someone crank it over?
 
Seeing this makes me want to ditch the planned +T and do a high compression engine & carb set up. . . . . . Excuse me while I go search craigslist for another 240. . . . . .
 
Hotdoggin said:
Are those carbs of dubious origin? Did you pop the bowls to see if they're clean inside? My car runs on a single 45 jet for the idle jet. You'll probably have to put a couple pumps in. Pull the choke with your hand, and have someone crank it over?
Click to expand...

Yamaha FZR1000 carbs. These carbs are super clean inside and out. Are you running 100% stock ignition?
 
ncbrock said:
Yamaha FZR1000 carbs. These carbs are super clean inside and out. Are you running 100% stock ignition?
Click to expand...

Yeah, but my harness has been gutted. Two wires leading over to the original Bosch ignition box, starter exciter wire, wires for headlights and the coolant temp sender. That's it. All I've got for wires in the engine bay. Stock bosch dizzy, bosch cap/rotor/bougicord wires and NGK plugs.

What is your car doing? Just cranking and cranking and cranking? Have you hit them with any starter fluid just to see if it'll roll over? I wouldn't do it too much, but I'd try at least one with a douse through the front end to rule out fueling. gashog said it, the ****er SHOULD run if it's got all the stuff it needs. I wonder if there's a fun spark cut somewhere? This is still CIS of some form.. Let me get my book out.
 
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It just dawned on me, my fuel pump is on switched power. It's on as soon as I turn to KPII. Are you relying on the original wiring which controls the fuel via the original relay and all that? If you wanna test for that function, gravity feed a few ounces of fuel into the carbs. Stick your feed line into a bucket for safety sake.
 
It's just cranking and cranking, no sign of trying to start at all. Had someone turn the dizzy full advance and full retard with no change. I have the fuel pump wired to what I think is stock wiring (it's been messed with before it looks like) so when then key is turned to ign, the fuel pump is always running. Had someone spray starter fluid and it still didn't even try to crank. But it's got strong spark and all the plugs are hooked up correctly. I'm 99% sure the mechanical timing is set correctly also from when I did the timing belt
 
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