Help smoking like mad !

V

Vmax540

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Joined
Jan 28, 2004
Messages
1,288
Location
Clarion Pa.
Website
vintagevmax.com
Rebuilt a Vmax540 from top to bottom and installed a new old stock oil pump (red dot) and it will load up under 3000 rpm and blows smoke like there's no tomorrow...... I mean alot of smoke ! I've checked and rechecked the oil pump cable per the service manual. It will rev up above 3000 but still bilows smoke like crazy. I've switched carb's with another know good set and it will still flood itself out. Any ideas ?
 
follow up:
we have switched out the oil pump with another red dot one... still tons of smoke.... so then we ran the oil injection lines back into the oil tank and premixed gas at 40:1... started it up and it didnt want to rev past 3000 like before and then bogged and shut down... now it wont start presumably because it is flooded... pulled the plugs and took the pipes of to let it air out a day or so and well see what happens next....the bottom line is there is a heck of a lot of smoke coming out with the oil injection system bypassed... although it may not have been cleaned out from before...does anyone have any ideas what the problem could be? anything... there is now such thing as a bad idea at this point!
 
the pistons have pins in them so that the ring gaps have to be seperated... they arent opposite but they arent lined up either... they are the way they should be... also i checked compression today and one side was 125 the other was 122... so i think im fine there... thanks for the advice though
 
To date we've tried different exhaust pipes, silencer, plugs, ignition coil, carbs and removed the oil injection and running 40:1 mixture. Question if a small amount of antifreeze was leaking into the cylinders how would a sled act and what would you see ? This thing bogs out below 3000 and spits fuel and oil everywhere. B.T.W. Remember the 540 had dual fuel pumps (Yamaha thought they needed the extra fuel) but, they never used this set up again? (Phazer, Exciter, Vmax5/600) I threaded the one pulse port and installed a lock tighted plug to go to a single fuel pump off a Vmax 600. Also, the 540 has a gear case on the side and I keep checking the level to make sure there is no cross contamination of fuel and if there was oil leaking into the crank case I'd see the level going down ? The bellowing smoke smells very much like 2 stroke !
 
when it is running below 3000 and bogging full choke will kill it, so therefore i believe it is a rich condition and not lean.... also if you pull either of the plugs wires off it will kill it, so that rules out running on one cyc.... could it be possible for this specific motor to not like the factory jet settings? if this was the case i would think it wouldnt vary enough not make it run sooo poorly on low end.... has anyone ever heard of a cdi not working correctly below 3000(or any rpm) from 3000-3500 it is just slightly boggy but below 3000 is the point of no return... what would that rpm have to do with? anything? also ill point out that above 3500 it is nice and snappy... the cdi has a bunch of wires coming out of it and this is just a shot in the dark, but... if one was loose or making a bad connection would that create this problem... i believe the anly part i havent changed out on this sled is the cdi and stator.... although prior to assembly the stator was checked over and deemed to be within the resistance ranges.....
 
got a few questions:

1.) are the carbs correct for a 540 vmax? have you verified the slide cut away size? float level correct?

2.)Are the carb slides in the same height on each one at idle/meaning there is the same gap at the bottom whn at idle? are the cables pulling the slides up at the same time? if you hold the throttle all the way open are the bottom of the slides level with carb opening roof?


3.) do you have access to a pressure tester for cooling system? if they inhale antifreeze it will fog for mosquito's but you can usually smell the anti freeze. Also when they drink anti freeze and the engines run the plugs will develope a green fuzz on them. if not run they will look to be oil fouled and shiny when removed. There also would be absolutely no carbon on top of the pistons??
 
hmmm hmmm hmmm vmax540(my uncle) is really trying to blame a leaky head gasket(or base gasket) but my radiator is still full and its smoking a whole lot... if it is leaking enough antifreeze to smoke that much shouldnt i be able to see the level drop? ive ran it quite a bit and its still only down a little bit... about the pistons tho... they doo seem clean still...(thats a very helpful tip) how long should it take to develop some carbon?... i dont know of any pressure testers i can get but if i find one how to i test it? is it like a cap a put on my rad.? what should the pressure be?
 
ya, the pressure tester goes on where the radiator cap is, you would pump it up to about 10lbs of pressure and watch it, if its dropping its seeping somewhere.
 
Good thought Mrviper I'll rig up a tester ! The carbs are stock Vmax 540's and we already installed another 540 set with no change and they are setup correctly. The pistons were completely clean after rebuild so, they're hard to judge by ?
 
Old school

Take a cold piece of tin/metal and place it close to and under the exhaust and start her up...the condensation is collected on the tin/metal, now here is the fun part taste it, if sweet, than anti-freeze. You would know if it was oil, it would be a dark depsit and not sweet...Now by chance was the sled stored with fogging oil or was it fogged the old school way pull the oil cable/pump wide open...If the old way was done and the person did not know enough to shutt down the engine, and he let it stallout by itself then there is a tonne of oil in there...so much so that it is not cycling and it is being drawn up through each stroke...also check and make sure you did not get the vent hose from the carbs mixed up and attached it to a oil line and it's sucking directly from the oil tank...Is the oil pump actually cycling or is it hung up wide open...I'm sorry I am not much help...But had a similar problem, the base was full of oil from a bad storage (fog) process…good luck please post back results...
 
mmmmm antifreeze... sounds delicious... ill try anything at this point... i rebuilt the motor so i know it isnt a fogging issue... ill let you know what i find out this weekend!
 
i did the exhast taste testing procedure and it wasnt sweet... as a matter of fact what accumulated on the stainless steel was kinda like burnt rubber... i could actually scrape it off... still havent done the the pressure test but that is next
 
Take a needle nose pliers and squeeze the pulse hose shut between the fuel pump and motor while the motor is running. After running a while, if the smoking stops and the motor runs better, there is fuel entering the motor through the pulse hose. With the changes you made, you may have hoses hooked up wrong or the fuel pump diaphragm is leaking -or the fuel pump incorrectly assembled.

Fuel contamination? Could there be any way that the fuel in the tank could have gotten anything in it other than gas -and the oil you added? Kerosene, oil, fuel oil/diesel, an additive? Possibly from a previous container it was in, or someone adding something that you don't know about? You could hook up a different container with known fresh, clean fuel.

Make sure that the enrichener cable is not pulling the plungers open. It could have been set wrong on both sets of carbs.
 
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Squeeze the fuel lines off with vice grips and let the motor run out of fuel. Could be that the bottom end is loaded with gas and you just keep adding more.
 
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