97' Vmax 600 Problem

nate01

nate01

New member
Joined
Dec 13, 2008
Messages
16
Age
39
Location
Canada
Please help*....
My father just re-built his 97' VMax XT 600....ran great and idled for maybe 1/2 hr and the rode around the yard a couple times....then we took it out for a run on the lake the next day....did runs from 10-70 mph and had a nice 50/50 mix tank...new plugs and seemed to pull just right....did about 35 miles and it quit....now when you fire it up...it runs rough and sound like its running on both cyl but cant be 100%....when you give it any gas it backfires and farts repeatdly.....we limped it back home and I figured it may be snow ingestion as we were in some pow pow....brought it home and thawed it out and pulled the carbs...they were not too bad but cleaned everything and re-installed....also disconnected the TORS to rule that out....also checked coil and plugs boot and there is great spark....also has good compression on both.....plugs are new....are a little wet obviously as its mixed fairly rich...but we cleaned very well.....its really werid...its like TORS because it pops and backfires and doesnt want to move but will a little.....dont know what to check next...need some direction or advice.....
 
will reeds actually make it run this poor.....it has gotten a lot worse....from the time it quit and limed back to the house.....till now....it barely wants to run now at all...I also noticed that there is some oil around the cylinder near the y-pipe on the throttle side....im very confused right now...
 
Make sure the spark plug boots are good and your getting good spark on both sides.
 
Are both cab slides opening? our 97 venture 600 had the screw that connects the shaft to from 1 carb to the other fall out, and it only ran on one carb until that was re attached. It also needed a carb sync after that.
 
im sorry yes 50:1.....but it may be even a little richer than that.....it has gotten worse trying to run it to the point where it will barely even run.....ALSO the choke seems to do nothing whether it be on full or off? Not real sure....the carbs are clean and everything seems good their....what is the fuel screw supposed to be turned out to? 2 turn from light seat? Dont know where to check next.....
 
Nate did you mix the gas in the tank w/ the oil pump hooked up? just a thought. Does it run when there is no load on it(on a stand)? check the exhaust and air box make sure a critter did not make a nest in there. Also take the air filter off the top of the airbox and try it, i had issues with mine the plastic cage was pretty beat up and at speed it would allow the foam to be sucked into the opening/cutting off air flow. if it runs on a stand with no load i would check the clutches. finally you might have to take the carbs off and go over them again
 
Well its not the carbs....they were put back together right and the airbox is in good shape as well as the foam on top....it doesnt even really wanna run by itself on the stand either....you start it and it will idle rough and you will have to give it small amounts of gas to keep it running and it will backfire and pop if you give it lots of gas but its always quits....its hard to keep running now....im not sure....there is lots of spark so i assume the coil/wires are still good....plugs are new...they are very wet but that obvious with the heavily mixed gas and poor running conditions....
 
slow down and take your time. sounds like its running really rich(since the choke changed nothing). did you replace the needle and seat on the float? Is the float height correct? If there is spark then its just a matter of getting the air fuel mixture right.
 
Also you say new plugs. Did you replace them after initial run? Also during breakin I thought you should run 100/1 in the tank. Of course along with your oil pump.
 
Well i would say that it is a minimum of 50:1 and could even be more like 40:1....I will change and try the plugs...although they look like brand new....also the floats seem to be in correct height and move freely...what would make it all of a sudden run like this though....it was running great and maybe got a little snow and immediatly made it run like crap....brought it home to try and thaw out...pulled the carbs and cleaned....still wouldnt run right...ill put some heet in the tank and new plugs in but im pretty sure thats not my problem....
 
Try to pinch off the fuel line. If it starts to clear up and run good before it dies you likely have carb issues, floats might have to be checked again. it just sounds like its very flooded.
 
horkn said:
Are both cab slides opening? our 97 venture 600 had the screw that connects the shaft to from 1 carb to the other fall out, and it only ran on one carb until that was re attached. It also needed a carb sync after that.
Click to expand...
Thats funny you say that. My inlaws have a xtc 500 and it ran like crap all of the sudden and I thought it was blown up put did compression and spark all good so I started removing carbs and while I was taking them out heard a rattle, and guess what screw came out and only one slide was opening. Put it all back to gether and its been perfect ever since. Maybe the tank premix yoiu did is just to much. Did you measure it correctly? Just thoughts.
 
YAMAHIZAL700 said:
Thats funny you say that. My inlaws have a xtc 500 and it ran like crap all of the sudden and I thought it was blown up put did compression and spark all good so I started removing carbs and while I was taking them out heard a rattle, and guess what screw came out and only one slide was opening. Put it all back to gether and its been perfect ever since. Maybe the tank premix yoiu did is just to much. Did you measure it correctly? Just thoughts.
Click to expand...
had that happen to my vmax last year with the same basic symotns as this posters sled ,if you had the slides out check and make sure after you put it back together the screw holding the throttle shaft did not come out.
 
Ok....left slides as they were and never took them off....they were moving freely and clean and right hieght...I will go over all screws again and double check everything but remember it ran fine and then ran like crap and THEN i took the carbs apart...so it very well may not be the carbs...I will however pinch off a fuel line and starve it and see when results I get....it is possible it was mixed to rich and will not run right....they plugs seem wet but not over-oiled....I would say at the worst it could be around 35:1 but that should still be fine and at the worst foul plugs....any other thoughts..?
 
ALso.....noticed that the one carb slide is a tad higher than the other and closes later....is this something that would cause me greif...?
 
Ok so tonight we pulled the carbs off again and went through...everything is fine...floats are at spec level and fuel screws are out 2 turns....We also re-adjusted the oil pump since it was WAY rich...also had the reeds out and had a good look and one has a slight chip off the edge of one side....dont think it will hurt performance as its very small but anything is possible....put new plugs in again and got it to run but very rough while it continuesly backfires....if you give it any throttle at all it will die....choke does NOTHING.....it died a few time and by the end of it the machine would no longer start....after it quit it would fire but not run...farting and backfiring still....obviously getting fuel...I still think its mixed to much esp with the pump being so high...is it possible that the fuel filter is plugged and casuing a problem....I just dont know whats next....all looks good with the carbs other than one slide looking a little higher...but very small amount....HELP
 
The problem with running premix and the pump is you are running the engine LEAN on gas. the oil/gas is mixed in the fuel pump and pumped to the carb mixed essentialy you are pushing 25:1 gas/oil mix instead of 50:1 then the oil that drops out leaves you with very little gas. It is very possible this is the reason it is backfiring and not running. The oil and such you are seeing is the excess you have as there is way too much in there especially if the oil pump was too high. I personally don't run any extra oil in the tank on rebuilds.
 
You must log in or register to reply here.


Back
Top