Beaver Posted May 28, 2013 Share Posted May 28, 2013 First up, I have done a fair bit of reading but have come across a few differnt trains of thought so would like to see what others have done as I know a few people on here are running bike carbs. So far I have come accross the following setups: Standard mechanical pump with pressure regulator fitted Electric pump with pressure regulator fitted Bike fuel pump (which turn on/off as required when carb float shuts off) What are people on here running? (Peter, Steve etc?) Are there any real benifits for any options? I guess an adjustable reg set to the correct pressure (see below for "correct?") woudl be the go, although seems a bit of a dick around getting a gauge to set the right pressure. Secondly, 3psi seems to be the most common pressure Ive come across, this agree with what you guys are running? Cheers Quote Link to comment Share on other sites More sharing options...
Goat Posted May 28, 2013 Share Posted May 28, 2013 Bike crabs are usually gravity fed (i don't know about new ones) Obviously you can't do this in a car. But you would need flow, not necessarily much pressure. Most jokers seem to run 3psi with a regulator. I'd just run your standard mechanical fuel pump with a fuel reg/try with out fuel reg first and see if it floods the shit out of it. Simple is best. Quote Link to comment Share on other sites More sharing options...
Beaver Posted May 28, 2013 Author Share Posted May 28, 2013 yeh newer bikes have pumps on them and quite a few people say usign the bike pumps is a good idea as it give sthe carbs the correct pressure without a regulator and they are just wired up 12v like a normal electric pump. alos, giz axle stand back ow Quote Link to comment Share on other sites More sharing options...
Goat Posted May 28, 2013 Share Posted May 28, 2013 Yup. I away tonight. Will pull them wed or thurs. Will be yours for the weekend. Dope Quote Link to comment Share on other sites More sharing options...
peteretep Posted May 28, 2013 Share Posted May 28, 2013 seriously, standard mechanical fuel pump is sweet. No reg required I am running a fancy facet high pressure/flow pump with a regulator, but its unnecessary Quote Link to comment Share on other sites More sharing options...
Beaver Posted May 28, 2013 Author Share Posted May 28, 2013 yeh? swish. you running a reg? Quote Link to comment Share on other sites More sharing options...
peteretep Posted May 28, 2013 Share Posted May 28, 2013 updated comment Quote Link to comment Share on other sites More sharing options...
Steelies Posted May 28, 2013 Share Posted May 28, 2013 i'll be doing a bike carb setup soon too beave. keen to jump in on this jazz/hijack i'm running a facet pump that currently feeds me pair of SUs what are the odds of this providing a useable pressure? tbh i'm gona hook it up and see what happens, but yeah just wondering. pete how did you go about jetting? Quote Link to comment Share on other sites More sharing options...
Beaver Posted May 28, 2013 Author Share Posted May 28, 2013 Sweet cheers Pete. Ill just try it without and have the fire extinguisher on hand.... Quote Link to comment Share on other sites More sharing options...
Beaver Posted May 28, 2013 Author Share Posted May 28, 2013 Manu, this could be a worth a read re: jetting http://www.classicfordmag.co.uk/2011/07/15/the-definitive-guide-to-bike-carbs/ seems to agree with othe things Ive read saying start at 2mm and got from there. If you end up too big solder back up and try gaina haha. but yes, also interested on what Peter did. I have two sets, one from a running a12 so hopefully wont need any tweaks Quote Link to comment Share on other sites More sharing options...
peteretep Posted May 28, 2013 Share Posted May 28, 2013 if you enter the facet part number into google, you can find out its pressure and flow ratings, there are so many options that you can quite easily buy a pump to suit an exact pressure I've had the fuel come out of the overflows many times but never a fire haha, stephen drove his car to taupo and back with the fuel overflowing due to clogged lines regarding jets, I personally think the best way to go about it is to drill the jet size to 1/100th the engine capacity as a start, but that is just from what I have seen and there are many different types/sizes of carbs out there. From my experience r1 carbs on 1800 xflow = 1.8mm r1 carbs on 1600 toyota thing = 1.6mm (this is what I jetted to but I believe he went slightly bigger after doing a road tune) gsx650 carbs on 1300 mazda = 1.45mm (I think we went too big on this so it uses a bit more gas than needed) Quote Link to comment Share on other sites More sharing options...
Steelies Posted May 28, 2013 Share Posted May 28, 2013 ha yes, i've read that article in the past but forgot where it was haha. chur pete! Quote Link to comment Share on other sites More sharing options...
Ned Posted May 28, 2013 Share Posted May 28, 2013 I tried it without a reg and it was pissing fuel out everywhere, but i was given some miss-information from one of the members here and needed more angle on my carb. I got told to put the carbs on such an angel that the top of the fuel bowl was level, but with it that way it would piss fuel out 24/7 so changed the angle by 5deg or so and it was sweet. The floats just werent quite pushing the needle closed properly, but by then i had put in a reg, thinking that was the problem. Never ran it without the reg so cant say what it would do without, but it'll probably be fine TBH. Only reason i'm putting extra effort into not having it spit out fuel is because it's a non cross flow and dont like the idea of spilling fuel onto a hot exhaust haha. I used '>this holley reg and worked a treat. Plus had 2 outlets for the 2 inlets to the carbs which worked out well. If you do run a bike pump, put it close to the tank, not the carbs as they dont like much restriction on the inlet but arent too bothered about the outlet apparently. Petes thing of 1/100th of the engine size pretty much follows what i read online also Quote Link to comment Share on other sites More sharing options...
Beaver Posted May 28, 2013 Author Share Posted May 28, 2013 yeh mine is also non cross flow so not too keep on petrol everywhere but will bolt it up and see what happens. Quote Link to comment Share on other sites More sharing options...
Ned Posted May 28, 2013 Share Posted May 28, 2013 you also cant run the overflows into a return, which would have been a good idea. I just run mine into some hose that runs all the way down to the bottom of the car to keep it somewhat away from the exhaust. Though if they overflow when driving, the wind will still kick it up into the engine bay probably, but i found it would only leak when parking on angles etc. I may even change the angle of my carbs some more for that exact reason, or plumb the hoses into some kind of reservoir i check every so often Quote Link to comment Share on other sites More sharing options...
KIRK Posted May 28, 2013 Share Posted May 28, 2013 the fuel pump on my Yamaha only primed the carbs when you turned the key on I think. I tested this by unplugging it and riding around. The bike ran exactly the same without pump haha. so yeh. Iduno Quote Link to comment Share on other sites More sharing options...
Steelies Posted May 28, 2013 Share Posted May 28, 2013 methinks the more restriction/tube length/reservoir etc on the overflows the worse they will work, and flood more..? ah damn i had assumed (always good) that the float bowl flange should be level. guess it's time to find out original mounting angle. Quote Link to comment Share on other sites More sharing options...
KIRK Posted May 28, 2013 Share Posted May 28, 2013 ^lots of bikes carb is on an angle. for packaging probably. like 10-30 degrees so I assume floats etc are set up with that in mind but you must be able to adjust float for change in angle? Quote Link to comment Share on other sites More sharing options...
peteretep Posted May 28, 2013 Share Posted May 28, 2013 bikes normally have like 400mm of line running to near the ground from the overflows r1 carb bowl flanges are level, but best to check your exact type Quote Link to comment Share on other sites More sharing options...
phatt20 Posted May 28, 2013 Share Posted May 28, 2013 all the semi downdraft type bike carbs iv used have not been fussy at all what sort of angle iv mounted them on, its sort of one of the main advantages over sidedrafts in tight engine bays, quite often tweak them up or down for airfilter clearance etc. in saying that i only use late model/good cond carbs , with a factory bike fuel pump. Quote Link to comment Share on other sites More sharing options...
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