Yamaha RD Startup

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teazer said:
I am very happy for you. Learning is great and there's no point in learning things if we don't pass that knowledge on to others. Glad it worked out.

i´m glad that there are people like you out there that share the wisdom!


so i´m pretty much down the road with restoing my RD,soon i´ll be able to do a firt start up.
what would you recommend checking before i start it up first?

de aeration of the oil pump is a must.
checking voltage on coil.
first start up with gas/oil mixture.which realtion?read something about 1:25.just to be sure that the oil pump works and has no air in the line.
should i squirt 2 stroke oil down the spark plug hole?

hope you can help me out!!
 
40:1 is fine for start up. Do not squirt oil down the plug holes. It will probably foul the plugs - unless you are talking just one or two drops only.

Kick it over a few times to free things up. Apply "choke" kick it over twice. Turn on ignition and fire it up.

Do it outside though. You do not want to smoke bomb your home or lungs.
 
can't you manually spin the wheel on the pump ? to get it all primed ?
i remember doing that i think
of course it would help to hold the throttle wide open as well to get max stroke
 
Glad to see your neutral switch problem turned out to be no big deal! I think I discussed priming your oil pump in a previous post - maybe not in this thread. I realize you do not have the manual wheel on your pump that we have on the older ones here in the US, (just as well - one less seal to leak!) but gravity should be fine with a bit of patience. I can't recall ever disagreeing with any of Teaser's advice, but I like rather a lot more oil than that starting a fresh engine. No doubt the oil you use will have an impact on how much is good, but the downside on more than is needed is minor and to my way of thinking irrelevant. Too little is definitely bad. In any event, if you assembled your engine with 2 stroke oil, it should be well protected for starting. I always simply start my engines normally after setting the oil pump to be richer than "normal", and making sure the lines to the carbs are full of oil. I can't remember what I shim the oil pump to off-hand (I don't want to offer bad info - I am traveling and can't check my memory), but I will try to report back when I get home in a couple of days. Your pump could also have more differences besides the absent manual wheel, so what I do may not even matter. Regardless, assuming your pump is working properly, once gravity has filled the supply line from the tank to the pump, you should be able to hold the throttle wide open (or hold the cable to the pump wide open) and kick the engine over and fill the carb lines. You will have to kick a lot, but it will work. Alternatively, you can start on premix, which is foolproof. If I did that, I would start a fresh motor at 20 to 1 ratio. There is no downside to too much oil until plugs foul on a fresh motor. For what it's worth, I am driving today a brand new 350 motor, now with 900 miles on it (within this week!), points/condenser ignition, oiled as just described, with the same spark plugs it started on. It smokes too much, but runs fabulous - can't wait to get it back home to dial down the pump!
 
jpmobius said:
Glad to see your neutral switch problem turned out to be no big deal! I think I discussed priming your oil pump in a previous post - maybe not in this thread. I realize you do not have the manual wheel on your pump that we have on the older ones here in the US, (just as well - one less seal to leak!) but gravity should be fine with a bit of patience. I can't recall ever disagreeing with any of Teaser's advice, but I like rather a lot more oil than that starting a fresh engine. No doubt the oil you use will have an impact on how much is good, but the downside on more than is needed is minor and to my way of thinking irrelevant. Too little is definitely bad. In any event, if you assembled your engine with 2 stroke oil, it should be well protected for starting. I always simply start my engines normally after setting the oil pump to be richer than "normal", and making sure the lines to the carbs are full of oil. I can't remember what I shim the oil pump to off-hand (I don't want to offer bad info - I am traveling and can't check my memory), but I will try to report back when I get home in a couple of days. Your pump could also have more differences besides the absent manual wheel, so what I do may not even matter. Regardless, assuming your pump is working properly, once gravity has filled the supply line from the tank to the pump, you should be able to hold the throttle wide open (or hold the cable to the pump wide open) and kick the engine over and fill the carb lines. You will have to kick a lot, but it will work. Alternatively, you can start on premix, which is foolproof. If I did that, I would start a fresh motor at 20 to 1 ratio. There is no downside to too much oil until plugs foul on a fresh motor. For what it's worth, I am driving today a brand new 350 motor, now with 900 miles on it (within this week!), points/condenser ignition, oiled as just described, with the same spark plugs it started on. It smokes too much, but runs fabulous - can't wait to get it back home to dial down the pump!

so somehow my life got inbetween my bike and me :)
i´m moving so the first start up will have a lil delay...hgowever im really thankful for all you helping!

so my assumption is,and this is how i´m gonna do it i guess:

1.)run with premix and oil pump

all oil lines were replaced with OEM quality ones so i´m gonna fill up the oil tank with 2 stroke oil,unscrew the dearation screw on the oil pump and let gravity do its thing (it has no dial wheel since its a newer model).


2.)pull choke,turn over 2 times then turn ignition key.

question here is:should i use a syringe and "fill up" the smaller tubes that go from the pump to the carburetors?

my guess is:after starting the motor with the premix i´ll let the oil lines connected to the carb (oil pump was primed as in point 1) then take the oil pump disk that is connected to the bowden and turn it full throttle so the small oil lines will fill up faster....is that right?

my fear with using an syringe is that the there will be air bubbles coming out of the syring i think this is the safer way to go...



i have 3 sets of new plugs already sitting around so if i foul a set i´ll change them and start again...is there a way to "clean" fouled plugs,maybe with acetone and a brush?

stupid question:
is the putting in the choke pushing it up or down?

thanks in advance for your help!!
 

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I run premix in mine exclusively. So I can't offer any advice on how to prime the system. I'm sure someone smart will chime in soon though ;)

As for the plugs, yes you can clean them up enough to reuse if you foul them up quickly. A little carb cleaner and a brush should work just fine.
Where is your choke? On the bar or on the carb?
 
Your plan sounds pretty foolproof, though excessive. Better safe than sorry though. If you are starting on premix like start up ratio (20-1 as previously noted - depending on oil), you will be super rich on oil once the injector is completely on line. Possible spark plug fouling is the only real downside besides way too much smoke. If you can run a temporary start up tank of pre-mix, or even just make up a quart of fuel pre-mixed and run it until the injector lines are full and then fill the tank with straight gasoline you will be fine. Prefilling the lines can't hurt, but if you are starting on full strength pre mix it is not necessary. One thing about the injector lines at the carbs: If you have clear lines, you will often see a big air bubble next to the carb, but a full line going down to the pump. That is because the air whizzing past the inlet siphons out a bit of oil near the carb. Don't worry, it is normal. I run clear lines for this reason, because I like to be able to look down and see oil is flowing! I do suggest this though: Once you have the engine running on premix, pull off each injector line one at a time, pull the cable to the oil pump so it is wide open (the pump only, not the throttle) and observe the oil pumping out of the line. Do it for both lines so you absolutely know they are both working. It is totally possible for one to work perfectly and the other to not work at all. Both should appear to work identically. The engine will speed up with the line off, but don't worry about it. There is no load, and the short lean condition will harm nothing. Even wide open, the oil pulses out more as an ooze than a squirt. You will definitely be able to tell if it is working or not once the lines are full.
As for the "choke", it is "on" when the brass plunger on the right side of the left carb is pulled up. That means that the lever on the left side is pushed down. The lever is horizontal, or "up" when it is off. Technically, it is a fuel enricher, and just opens a big fuel jet to dump in some gas when engaged. The rubber tube that connects the two carbs feeds this to the right side carb, which does not have the "choke" at all. Might want to check that the fuel bowels are on the correct carb. The left bowel has a small drilling in the bottom to feed fuel to the enricher. swap bowels, and you will be super frustrated on the first start up. A real common oversight! Remember, this is for US models, and I am assuming yours is the same.
 
Hey moeb thanks for your expertise!!
I will check on the right position of the fuel bowels.
Could you point me out the part number on the diagram so i will be able to find it?
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Part 11. They look the same but only one cylinder has a "choke" so you need the correct bowl on the correct side.
 
Right. You can simply look at the two bowels carefully to determine which one is which. As usual, I am making the assumption that your machine is the same as US RD's. Also as usual, the key to everything mechanical is understanding how it works, not just what part goes where. Look at the two fuel bowels (part #11 - compliments teazer!) side by side, and you will be able to spy out that they are not the same. The left carb bowl has a very small hole drilled in what looks like the bottom, but it is drilled at an angle so it intersects with a vertical cast-in "pipe" that feeds the fuel enricher system that is the "choke". The other bowel looks the same. It has the same vertical 'pipe" cast into it, but there is no hole drilled. In operation, because of the hole, fuel fills that pipe to the same level as that in the bowl. When you "choke" the engine to start it, you are only opening a valve that lets the engine suck fuel from this pipe. On an RD, the passageways past the "choke" leads not just to the bore of the left side carb, but also to the connecting hose (part #50) that goes to the bore of the right side carb, supplying it with extra fuel for starting as well. The left carb obviously is the only one with the choke plunger, so if you put the right side bowl on that carb, nothing happens when you engage the choke because there is never any fuel in the pipe to supply the enriching circuit because there is no hole to let the fuel in. I'm calling that drilling a hole, but technically it is a jet. It is drilled to a specific size to supply the right amount of fuel for cold starting. While I am thinking about it, also be sure to put the correct slide in the correct carb (part #26). The bottom edge of each slide had a horizontal side and an arced side which is called the cutaway. The slide throttles the amount of air going into the engine, and the cutaway impacts air volume at idle and low speed. Different cutaways are available to adjust the tuning of a particular carb to a particular engine. So it is a tunable component for air sort of like most jets are for the fuel. Just make sure that the horizontal lower edge goes toward the cylinder side, and the arced side goes toward the air cleaner. The slides are mirrors of each other and will assemble backwards as easily as correctly, so it is a super easy mistake!
 
Hey moeb!

So i checked my bowls.you are sooo right there is a drilling in one of the two.
I had that bowl mounted on the left side (choke side).so i guess it is mounted right?
I checked also if the drilling is free and liquid can travel trough...the liquid comes out of the bigger drilling (marked with blue arrow).

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I also checked the slides....the angled part was mounted backwards as you can see in the pics.

Does one slide come in a certain carb or is it possible to out them in any of them?

I checked the manual and tried to check the markings of the slides trough the side maintenance holes closed with the screws.
As you can see in the pic the marking is only a tiny bit showing in the drilling so is this ok or should i move both slides up a bit?

Pics show left and right carb

And

Position of carb markings

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Last question:

As i was disassembling the carb bowls i checked on the float levels.

The left float lvl is around 29MM.
The right one is 31-32 MM.

Are the floats mounted right with the 'angled' part up,as shown in the pic?

I tried to adjust to right one to 29MM but i wont work.i bent the the tiny flag in order to adjust it but even with the hardest bent it wont go up or down....so my guess is that the tiny needle with the brass pin is old and worn out.

Is that possible that it keeps the float lvl from readjusting.
I tried to 'engage' the float mechanism by pushing up the float and realised that the needle with the pin moves out and back in of its seat way more than the one of the left side.
Should the needle stay in place or move up and down with the float flag moving?

Plz watch the tiny vid to see what i mean

Made a pic of the bent flag of the float

Guess i'll need a new needle or the seat is worn....



https://vimeo.com/110403948

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The slides are correctly oriented in the pics. The cutaway which is visible on the left (first pic, right side carb) faces the inlet side. The number stamped into the slides indicates the size of the cutaway, so if you are setting up carbs for an unknown application, you can exchange the slides you have with slides that have a different cutaway, similar to changing jets, or needles to tune the carb. On your RD, the slides are identical except for the right/left handedness, which is done so the idle set screws are outboard on both carbs. Otherwise, you would have to reach between the carbs to get to the idle screw on the right side carb. as far as I know, the "maintenance" bolts are only there to see the relative location of the slides for setting he idle speed. When you set up the carbs, unscrew the idle stop screws ( the big knurled hand turned screws on the outboard side of each carb) so the slides are resting on the bottom of their bores. You may have to adjust the throttle cable at the grip to get enough slack. If needed, you can get more slack at the carb tops with the cable adjusters there. Once both slides are completely closed, adjust them so they start to rise exactly at the same time when you twist the throttle grip with the carb top cable adjusters. Make sure the carb tops themselves are screwed down all the way and just snug against their rubber gaskets first. If you can't look directly into the bores, you may be able to stick one finger into both carbs at the same time and feel when the slides just start to lift. Adjust the cable adjusters until both start lifting at the same instant. This ensures that the slides are synchronized. Next are the pilot air screws. Those are the small slot head brass needles with the spring under them that thread into the left side of each carb body just above the bowls. The tapered end of the needle fits into a tapered passageway, and when screwed in all the way seals off air going into that passageway. Screw the needles all the way in, but not too tight as the needles are brass and the carb body is aluminum and both mushroom out pretty easily, and you are only looking for the reference point of fully closed. Unscrew the needles 1-1/4 turns out and leave them there. When you do this, you are setting how much air is allowed to mix with the pilot fuel system at idle. You can fine tune this setting later, but as long as the carbs are clean, just set it and forget it for now. That is all you need to do to have the carbs ready to get the motor started with one caveat; Since the Idle stop screws are out all the way, your engine will not start and run unless you twist the throttle grip a little. Otherwise the throttles will be completely closed. An alternative is to screw the idle stop screws in a bit to guess at an idle, but if you go too far, your engine may start and run at a very high speed until you re-adjust. So look into the carb intakes with the throttle closed. Start screwing in one of the idle stop screws, and when it contacts the slide, you will see the slide start to lift. Screw it in until the slide is open a millimeter or so above fully closed. Look through the maintenance hole and screw the other carbs idle screw in until it looks the same, or simple look into the carb intake and repeat for that carb. Once you have the engine started and warmed up, you can set the idle speed by adjusting the idle screws. If you start it and the idle is way too fast, just back out the idle stop screws accordingly so you can get it warmed up. Looking into the maintenance holes, with the bike idling, adjust the idle screws so the indicator in each carb is in the same place with the idle at 1200 rpm or so. Older carbs do not have this maintenance port, so you simply place you hand close to each exhaust outlet to feel the exhaust pulse and adjust until they feel the same at the idle speed you like. Once done you will probably have quite a bit of slack in the throttle cable at the grip, so adjust it out at the single adjuster at the grip. If you need more slack removed, you can get it by adjusting at the carb tops, but you will have to re-synchronize the slides if you do so unless you are super careful to make the exact number of turns on each adjuster.

As far as the float level goes, I can not tell you the correct spec for your floats as the US RDs have separate dual floats, not like yours. But, it is important to understand the valve first in order to be able to set the float once you have the spec. A lot of people seem to be confused by the float needle. The needles you have are made with a tiny spring loaded pin that contacts the float arm. This spring loaded pin does not interact in any way with the flow of fuel through the needle and seat assembly, it is just a mechanical shock absorber and pressure regulator for the force of the float mechanism on the needle. Usually when you are adjusting the float height, the pin should be completely uncompressed. On some carbs, holding the assembly upside down will slightly compress the spring loaded pin due to the weight of the floats. If you set the level this way, the operating fuel level in the bowl will be too low unless the measurement is supposed to be done this way and the weight is taken into account. So you need the specification and the method used to make the measurement. As far as the spring loaded pin goes, you only need to be concerned that it works freely. Submerge the needle in some gasoline and stroke the pin a few times. It should be totally smooth with zero resistance or binding aside from the spring pressure. If not, submerge it in carb cleaner until it is, then repeat with gasoline. Otherwise replace the needle and seat assembly. I can not see in your pictures how the float goes, but you can invariably see how by the wear mark the spring loaded pin on the needle makes on the float arm tang.
 
Hey moeb,

Had this weekend time to mess around with my float levels.

Checked my workshop manual,it shows the float lvl with the carb upside down.

So my question here is:

When i adjust the float lvl upside and afterwards i flip the carb back into its normal position the lvls dont match,although they matched when upside down.

This happened on the right side carb.so i took out the needle of the left one tried it again and it worked properly so i guess my needle is effed and i need a new one.
Is there a good reliable way to check the function of needles and seats?

Maybe i m just way to worried cuz the float bowl somehow 'closes' the whole thing up and the upside down issue is just fugazi by me.
 
It doesn't matter if they match when right side up and the floats are hanging. Probably there is a little tang on the float arm that controls the open position. Probably, you can completely ignore it, but here are two things to consider if you are interested.
First, the float must be able to travel down enough to open the needle and seat enough so the carb never starves for fuel. Very unlikely this would be an issue, but you can check if you are concerned.
Second, the float should not be able to hang so low that the needle can partially escape the housing and jam the float open. Unlikely this is possible with the bowl on, but it would keep you from losing the needle accidentally with the bowl off.
 
I will replace both seats and needles.
Altough i adjusted the tang the needle on the right side did escape and blockef the float open when i turned the carb back after adjusting to the 'upright' position.

Another question:

Is there something like a 'leak down' method for these kind of carbs?

For my kz400 i just connect the carbs to a external fuel tank open up the petcock and check if the fuel stays in.

I just want to check the possible 'leakage of my carbs' before i start the RD and poor gas all over the freshly painted motor (prob causing the paint to dissolve).
 
I never replace needles and seats unless there is a problem. Yes, checking is simple. Install them (or bench check with an overhead tank) and see if they overflow. They somewhat commonly stick after a fresh carb rebuild, but tapping the bowl with a screwdriver handle should shake it loose. I always install drain hoses on the bowl overflows too 'cause once in a while the needles will stick for no evident reason especially if you forget to turn off the petcock.
 
I ll bench test them to get sure they dont leak.
So am i right that when the carbs there is a problem with the seat/needle,i m just asking in case the carbs will leak.

What do you normally do when the carbs keep on leaking?
The needle should shut off the fuel supply normally.
Thx for your input!!
 
So i got great news...

This shows how little things can do big big stuff.

I replaced the old seats and needles on both carbs...the seats seemes fine but i just wanted to sort out that these could cause trouble...

And then i found what you calles 'tang'...:) i ' m a douche and now the float is nearly at the same lvl upside down and the other way around....

All the time i thoughy that the 'tongue' that touches the needle is solely responsible for the carb float lvl...i guess this is how i learn stuff....^^

Before it was:
29 MM upside down
36 MM other way around

Now its:

29MM upside down
29-30 MM othrr way
 

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