97 VMAX SX 700 Triple Bog

4

4wealn

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Joined
Feb 11, 2015
Messages
129
Location
Ontario, Canada
Hello all, I decided to get the sled out and have a once over before the weather changes. I fired it up after about 15 pulls (had sat since April or May). It fired up, was a bit hesitant initially like it wasn't running on all cylinders, then the nice raspy triple sound came on. It was running great and then all of a sudden it dropped idle to almost zero and puttered out. I pulled it twice and it wanted to start but would not unless I gave it the first step on the choke. It started right up and I removed the choke. It ran great for about 10 sec and then did the same thing and sputters out. I fired it up again the same way with the choke and then removed the choke. This time as it was dying out I gave it throttle and it picked up once and then it still wanted to die. I kept on the throttle and it lost its raspy sound and almost sounded like a sewing machine and died but not without a loud backfire. I got it started again and it sounded great and again after 10 sec.....same thing, bogged out and died.

When the sled was put away for the season I ran ring free and stabilizer from Yamaha in it like I do every year. It ran great when I put it away and have not fired it up since then until this past Sunday. Not sure why this is happening. This is the first time I have had issues with it running. It only has 2700 miles on it. It is a red head.
The carbs were cleaned last year by a dealer and I only ran it for 20 miles last year (we didn't get a lot of snow last season).

I did pull the plugs to have a look and they looked wet. The clutch side and center plug I pulled out and they looked the same, when I pulled the mag side there was smoke coming out of the plug hole and the plug looked like the other 2.

I am thinking coil or CDI, but why does it run great for 10 sec and rev up great and then bog and sputter and die.

Has someone seen this before to give me a place to start. I did not have time to diagnose anything like ohm out the coils, etc.

Plug boots were new last year.

Thank you in advance.
 
It could be leaky needles and seats, not a huge problem on yamahas but is super common for polaris xlt's and xcr, I would personally pull carbs and make sure float height is good first. Also if u havent yet disconnect tires, and see if that changes things
 
you need to polish the flywheel for it to fire on all 3 cyl. just went through this with a 97 sx700 redhead my brother picked up that started running like that. replaced the fuel filter and cleaned the carbs 1st, then plugs and no improvement. pulled and wire wheeled the flywheel and she lit off on all 3 cyls and ran up to temp with all 3 running. starts and runs great now.
 
Its sat since may, I would start with cleaning the carbs and see what happens. I have seen carbs gum up even with fuel stabilizer.
 
If it only runs with the choke partially on that is pretty much guaranteed the pilot circuit has crap in it.
 
It will run with the choke off, and runs great, but it just slowly after 10-15 sec drop the idle and stall. Once it starts tp stall if you hit the throttle it does not want to pick up again. To get it started again without holding the throttle a bit I put the choke partially on and it fires up again. then the same thing happens.
I will see if I can get a sound clip of it or a video and post it.

All great responses.
 
Sounds like the bowls are emptying and not refilling quickly enough?
I can’t imagine this being anything but dirty carbs
 
UPDATE: So I had some more time to play today. It did take about 6 pulls to start and when it did it ran good with the choke up on step. after the choke was off it ran good and throttled up but after about 15-20 sec the throttle was not responsive and it idled down. Feathering the throttle brought it back up but as soon as I didn't touch the throttle it puttered out to an idle of 0 rpm and stalled out. I am now more thinking the carbs need a once over. I looked inside the air box and it was clear so no nests or anything. Time to pull the carbs. That is something I have not done. I am not nervous about opening up the carbs, just nervous about setting the oil cable so I don't have it run lean and hurt the motor. Any tips for this. I did take a video of it running but not sure I can post the video here.
 
How easy is it to swap out a new filter. Can I pull the line from the front of the tank when the air box is removed. I see the line that comes out of the tank. I do have a new filter.
 
You can fish for it with a wire coat hanger or similar tool, then pull it through filler hole.
Just be careful not to hook the float.
 
Thank you everyone for the advise. It ended up being a plugged pilot jet in one of the carbs. Who would have known that the carbs could be dirty after 20 miles last year.
I have never removed and cleaned the carbs myself. I always had taken it in to the dealer as I was afraid I would not set up the oil cable properly. It turns out that you do not need to touch that cable. It was very easy to remove, clean, and re-install them. That will be on my fall list every year now.
The sled started up and ran great. Only thing left to do is to replace the fuel filter in the tank. I pulled it out but the one I had would not fit so I will be ordering one from the dealer along with the fuel line as it is pretty hard and as stated here short so a bit longer would make it easier to replace in the future.

Thank you everyone for all your help.
 
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