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petcock question
- Thread starter codyxs400
- Start date
gpounce32768
XS400 Enthusiast
I checked my float level as per post #34 in this thread- with tubing and so on. This is for an '82 XS400- since you have an '81 the float setup may be different.
If you mean the needle valve w/ the diagragm and slider thats a different adjustment- would be good to check the needle setup against whatever your source of service data says. Mine was in OEM position.
Of you mean the float valves, the float pushes them against their seats to stop the flow of gasoline into the bowls. If the floats are set wrong then either too much or too little fuel will be in the bowl.
If you mean the needle valve w/ the diagragm and slider thats a different adjustment- would be good to check the needle setup against whatever your source of service data says. Mine was in OEM position.
Of you mean the float valves, the float pushes them against their seats to stop the flow of gasoline into the bowls. If the floats are set wrong then either too much or too little fuel will be in the bowl.
thanks fella.as I said in one of my last posts I set the floats from a vid I saw on utube just wondered if you had another way of doing it .anyways good news .rigged up a make shift small tank of fuel ,connected it to the carb .started the bike fired up straight away but wouldn't idol. adjusted throttle stop screw got it to idol.tiking over perfect nice pur coming from the engine. I then played around with the air mixture screws .3.5 turns out from seated. screwed them in 1 full turn on both carbs engine started to die so turned back out.3.5 turns seems to be the sweet spot.before adjusting the floats I had a popping sound from left exhaust it has now gon.the carbs being linked with a piece of fuel pipe and this was the only way the bike would idle. I've capped each carb individually. it now runs with carbs not being linked just to check petcock vacum.Happy days.i havnt had the bike out for a drive I'm hoping I will get over 60mph with ease.if not I'm going to adjust the needle valve by raising it one position. so stay tuned.I also have a question. when starting bike from cold left exhaust is smoky ,blue smoke as the engine warms it vanishes.is that worn piston rings ?also the engine breather, some light blue smoke coming from it .is that normal?thanks to all u guys for help and advice appreciated.
I would reset the air screws (idle jet screws) to the factory settings first. Based on your elevation above sea level, you'll have to adjust them anyway, but the factory setting will usually get it running. On my 1978, the factory spec was something like 2 or 2.25 turns out. Then I tuned them so that I got the highest idle speed which where I am was something like 3.5 turns out. Once you can get the bike running/idling, slowly adjust both idle jet screws 1/4 turn at a time and the idle should raise. You want to be careful that the idle doesn't raise too much or the carbs will transition from the idle circuit to the main jets, so you want to keep turning the main idle speed adjust screw to lower the idle back down, then continue adjusting the idle jet screws. You'll get to a point where turning them out a 1/4 turn will lower the idle. Turn them back 1/4 to 1/2 turn, then set you final idle speed screw to the 1200 rpm. Good luck!
Eh... Everyone gets there at some point...
I have an XT350 in the garage right now that is tempting me to take out it's carburetor with a shotgun.
It kind of sounds like you are making progress, tho.
3 1/2 turns seems like a lot. But that may be just compensating for those cone filters.
I really don't get the obsession people have with those. They filter worse than factory (let more dirt in), and they give you a tuning headache. Unless you changed frame geometry to where your normal intake just won't fit, there is no upside to them. You don't look like a racer, you look like every other dude who spent 20 bucks on eBay.
thanks yes getting there slowly but surely. I've ordered another 2 cone filters as the others are filthy that can cause plugs to fowl to.take care with that shot gun .lolEh... Everyone gets there at some point...
I have an XT350 in the garage right now that is tempting me to take out it's carburetor with a shotgun.
It kind of sounds like you are making progress, tho.
3 1/2 turns seems like a lot. But that may be just compensating for those cone filters.
I really don't get the obsession people have with those. They filter worse than factory (let more dirt in), and they give you a tuning headache. Unless you changed frame geometry to where your normal intake just won't fit, there is no upside to them. You don't look like a racer, you look like every other dude who spent 20 bucks on eBay.
Plugs mostly foul with oil and soot.
What crappy filters do is let cruft into the carbs and make you clean again. And if you ride some place dusty, you can wear out the engine prematurely. Dust is a fine abrasive.
If you do get new filters, look for UNI foam filter pods. Much better filtration than the mesh and gauze cones. Racers can get away with crappy filters because they rebuild their engines constantly. Normal people should use normal filters.
Yeah, working on that...
thanks for that
manual settings are 1 and a quarter turns out from seated.tbh I never tried it but don't think the bike would idle with the air screws at that setting. I could give it a go.ive got a carb tune 2 coming and will get this rigged up.apparently these are good for tuning. we'll see .thanks
ok pal.thanks for thatPlugs mostly foul with oil and soot.
What crappy filters do is let cruft into the carbs and make you clean again. And if you ride some place dusty, you can wear out the engine prematurely. Dust is a fine abrasive.
If you do get new filters, look for UNI foam filter pods. Much better filtration than the mesh and gauze cones. Racers can get away with crappy filters because they rebuild their engines constantly. Normal people should use normal filters.
Yeah, working on that...
back in the day I was told set the air screws that give you the fastest idle then lower the idle with the throttle stop screw?
I live in Scotland. no need to worry about dust here.always wet.lol
does anyone know about the blue smoke ?
I think it narrows down to worn rings/cylinder wall finish and/or bad valve guide oil seals in the head. A compression test of the cylinders would tell you a lot about the rings/cylinder wall wear.
ok thanks for that
That might be valve stem seals. Oil leaks past them while parked, then once it burns off, it's clear.
thanks .would it be a good idea to get them fixed or just keep an eye on the oil level. not by myself too technical for me.
God anyone got a match.back out to check the bike.fired up first go.struggled to idle after engine was warm turned the revs up using the throttle stop screw tiking over fine was Even running using the petcock vacuum . realised it was low on fuel .put about a pint of fuel into the tank.bike went haywire wouldn't idle atall ,back firing to .even setting it up with fuel line going from carb to carb when it previously ran ok before was not working either. did take the plugs out before hand to check them.one side suity and one side ok.gave them a light clean with a wire brush.now when reving the bike it's very choked and misfiring not idling .I'm really scratching my head now lol .have I accidentally disturbed the plug gaps and put crap fuel in.removing the plugs and putting fuel in is the only 2 things I've done.can see this going to the motorcycle shop or a divorce is looming .any ideas anyone
Sure the lads at the filling station haven't been pissing in the holding tanks?
If adding fuel is all you did, could be either fuel is no good, or you had something in the tank that got stirred up or knocked loose. I nearly killed my car a couple of weeks ago by putting leftovers from the can I use for yard equipment into it.
If adding fuel is all you did, could be either fuel is no good, or you had something in the tank that got stirred up or knocked loose. I nearly killed my car a couple of weeks ago by putting leftovers from the can I use for yard equipment into it.
