So this attaches to the petcock, but it doesn't receive fuel? Sorry I'm still a little lost, to clarify I do not need to supply fuel to this port?
I haven't got around to cleaning out the gas tank and petcock yet, but I am trying to rig up the carbs with a small amount of fuel just so I can attempt to get this thing started.
So this attaches to the petcock, but it doesn't receive fuel? Sorry I'm still a little lost, to clarify I do not need to supply fuel to this port?
I haven't got around to cleaning out the gas tank and petcock yet, but I am trying to rig up the carbs with a small amount of fuel just so I can attempt to get this thing started.
If you haven't cleaned out, sealed the gas tank. And cleaned petcock. You're running in circles and creating more work and headaches for yourself. I presume that that there is definitely rust in your tank. With these bikes, you have to address that. No if, ands or buts about it. It will cause problems. It's a real pain in the ass to keep removing and reinstalling carbs. At the very least, add an inline fuel filter if you want to hear it run. Shame you would take that route though. After all the work on cleaning the carbs. The spigot you pointed out is for the vacuum line on the petcock. That line allows fuel to be sucked to the carbs while it is running. The spigot below it is for the main fuel line. If your middle carb is overflowing. Your float height is incorrect or your needle valve is not being completely compressed as a result of higher and incorrect float height. Or the needle valve is junk. Could aslo have a particle blocking the needle seat. Also, don't make the same mistake I recently made with the horizontal hoses to each carb not being wire clamped. The hoses may look tight enough with the eye. But, they can leak if not clamped. Possibly, making you think the leak is from somewhere else.
So this attaches to the petcock, but it doesn't receive fuel? Sorry I'm still a little lost, to clarify I do not need to supply fuel to this port?
I haven't got around to cleaning out the gas tank and petcock yet, but I am trying to rig up the carbs with a small amount of fuel just so I can attempt to get this thing started.
If you haven't cleaned out, sealed the gas tank. And cleaned petcock. You're running in circles and creating more work and headaches for yourself. I presume that that there is definitely rust in your tank. With these bikes, you have to address that. No if, ands or buts about it. It will cause problems. It's a real pain in the ass to keep removing and reinstalling carbs. At the very least, add an inline fuel filter if you want to hear it run. Shame you would take that route though. After all the work on cleaning the carbs. The spigot you pointed out is for the vacuum line on the petcock. That line allows fuel to be sucked to the carbs while it is running. The spigot below it is for the main fuel line. If your middle carb is overflowing. Your float height is incorrect or your needle valve is not being completely compressed as a result of higher and incorrect float height. Or the needle valve is junk or you have a particle blocking the needle seat.
Thank you everyone for all of your knowledge and help! This forum has been such an awesome resource and full of good people.
My tank is indeed rusty and it will be cleaned and lined before I attach it to the carbs, I wouldn't dream of using it in its current condition. The carbs are on, but I still need dust boots, filters and adjustments to be made so they aren't yet permanently affixed. I will take some pictures later to show how it is currently configured, but I am trying to see if I can get the bike to start without the gas tank on. I know the bike sat covered outside for at least a year and a half from the guy I purchased it from, but it wasn't running when he got it either so I really have no idea how long this motor hasn't turned over. That is precisely why I want to get it started asap so I can know ahead of time if I have any big issues in the motor before I keep putting more money into other bits. I did get a look at the pistons from the intake ports and did not see any visible rust so that was a good sign, and when I removed the heads there was no rust there either, just some carbon on the piston tops. I just know that I have a long way to go before I get this bike into the shape that I want it and hearing that motor purr would really put a pep in my step.
I know the feeling of wanting to hear it run. Any shortcut is worth hearing the motor fire up for the first time. As far as wanting some relief that the crank will turn and the pistons are not seized. All you have to do is remove the points cover. Attach a socket and wrench to the nut in the middle of the points plate. Give it a complete turn, if it turns your crank and pistons are free. It's an easy reinsurance inspection in reference to acquiring an old bike that has been sitting. As long as the pistons aren't seized or fractured. Chances of you having any major motor problems are very slim. Unless, the clutch or gears are bad. That's not hard to fix either. A little more expensive and time consuming. But, nothing to be worried about. These bikes are very old. Expect little issues. But, for the most part. The motors are bullet proof and the bikes themselves are easy to work on and fix. Most difficult aspect of maintaining these bikes are keeping the pigs clean. Your bike will be what time and love you put into it. Then there's your bank account.
The circuit you outlined in the photo on the previous page does not receive fuel It is an air passage only. It is strictly vacuum. There is another hose the goes between the spigot on the rack and the petcock. When the motor runs, a vacuum is created. That vacuum causes the petcock to open and allows fuel to run. When the motor stops, there is no more vacuum and the petcock closes - shutting off the fuel. Simple, but looks complicated.
Be very careful when you disassemble the petcock. The diaphragm rubbers are NOT available. I use a dull pen knife. Slowly work you way around till you have everything separated. Buy a rebuild kit that includes the tiny o-ring you will find on the plunger inside. That 0-ring must be replaced. 95% of petcock problems are caused by this o-ring being hard or cracked. Also make sure there is no corrosion on the o-ring seat. It's pretty simple to see how it works once you take it apart
IMPORTANT! If you are going to start the motor with an accessory tank, you MUST cap off the spigot for the vacuum line. If you don't, you will have a massive air leak and the motor will run like sheet.
I was born with nothing and still have most of it left.
Thank you all for the input about the carbs. I haven't got to fire it up yet, but I am getting closer. Before I do, I just wanna make sure everything is in decent shape for it's first kick-over. I forgot to mention these T-tubes in between the the carbs, it appears that someone snipped off the "T" on these and now there is just an open hole on both. I imagine I need to go buy new ones, but where do these hoses go if they were attached to the T? I couldn't find any pictures of this on http://www.oldjapanesebikes.com/mraxl_G ... cover.html" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; or in the parts diagram. Can these be plugged off or replaced with just a straight horizontal attachment?
The T-pieces have a clear tube facing towards the rear of the motor. The T-pieces are to allow the float chambers to vent so that they are are atmospheric pressure, so don't plug the snapped off piece! You cannot buy them as new spares, but you can probably get an old set from a breaker. I wouldn't bother doing anything with them for now, if ever.
The RH carb gets rich / choked mixture through a connecting rubber tube joining the front side of the centre carb to the RH carb. I have no idea why LH and C have choke plungers and the RH doesn't, but the 380/550 ganged carbs are the same here. If you peer into the intake ends of the LH and C carbs, you will see that the choke air intakes are of different diameters, larger on C.
Cheers,
Mike
I think i would be tempted to rotate those bowl vent coupler pieces so the hole points down just to help keep water out being there isnt a way to attach the vent lines to them any longer.
Anyone live near a Jeep dealer that could check this part to see if it could be made to work for the bellows section ? http://www.ebay.com/itm/Military-Jeep-A ... 4615339997" onclick="window.open(this.href);return false;
Too bad the listing isnt for all those parts .. its just for 1 float , but there are what looks like some good 380 carb spares that will come up . I suppose the seller could be contacted to get a price on what is needed ?
As far as wanting some relief that the crank will turn and the pistons are not seized. All you have to do is remove the points cover. Attach a socket and wrench to the nut in the middle of the points plate. Give it a complete turn, if it turns your crank and pistons are free. It's an easy reinsurance inspection in reference to acquiring an old bike that has been sitting. As long as the pistons aren't seized or fractured. Chances of you having any major motor problems are very slim. Unless, the clutch or gears are bad. That's not hard to fix either. A little more expensive and time consuming. But, nothing to be worried about. These bikes are very old. Expect little issues. But, for the most part. The motors are bullet proof and the bikes themselves are easy to work on and fix. Most difficult aspect of maintaining these bikes are keeping the pigs clean. Your bike will be what time and love you put into it. Then there's your bank account. 
