1997 Vmax 700 SX bogging

A

asphaltlou

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Nov 12, 2017
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Hi peeps. I have a 1997 Yamaha Vmax 700 SX I was told that this sled runs amazing but needs carb cleaning. Well carbs were very clean and the jets were in good shape and clean. My problem is there is a low to mid range bog that I can't get rid of. Im not sure if its in the needle or not. It has 45 pilots, fuel screws 1.5 turns. 145, 143.8 mains. 1.2 needle and seats. The needle I have no idea what it is. I see it is suppose to be in the #3 position. But I haven't checked. How do i remove the needle. Thanks!
 

https://totallyamaha.com/snowmobiles/aaTECH/carbs/Carbs.htm FOr needles

https://totallyamaha.com/snowmobiles/aaTECH/CarbNeedles/CarbNeedles.htm For needlses

https://totallyamaha.com/snowmobiles/AAATuning Chart/Specs.htm Stock specs

I doubt your bog is from your needles. It sounds like the typical SX bog, and It can be cured by adding reed spacers or doing the reed stopper notch.
I cant remember the science behind why this works but it does. https://totallyamaha.com/snowmobiles/aaTECH/ReedNotch/Reed_Notch.htm
 
super1c thank you. The sled has vforce reeds also. I believe they are the first version. I know they arent 2s, and I'm pretty sure they arent 3s. Also I noticed there is a backfire if I hold the throttle around 3500-4000 rpm. Im not sure where that is coming from as well. Thanks.
 
asphaltlou said:
super1c thank you. The sled has vforce reeds also. I believe they are the first version. I know they arent 2s, and I'm pretty sure they arent 3s. Also I noticed there is a backfire if I hold the throttle around 3500-4000 rpm. Im not sure where that is coming from as well. Thanks.
Click to expand...

The backfire at 3500-4000 also leads me to think you may be dealing with a Tors (throttle override) issue. To test find the bullet connectors comming off the carbs and see if they are plugged into the harness. If they are unplug them and plug them into each other at the carb side and from the wire harness side. So the carb bullets are plugged into each other and harness end is plugged into each other. If this fixes it most likely your throttle cable is to tight. It should have a good amount of slack to it. You only need it right enough to bring the throttle lever on carb all the way up.
 
how many mile on the sled?--could be weak reeds (most will say Yamaha reeds are best)--spark plug caps? (check for correct ohm reading)--weak stator--are the plastic parts that hold the choke plungers cracked?--Tod
 
how many mile on the sled?--could be weak reeds (most will say Yamaha reeds are best)--spark plug caps? (check for correct ohm reading)--weak stator--are the plastic parts that hold the choke plungers cracked?--are clutches in good shape--center to center--offset--belt?--check that the motor mounts are all tight--Tod
 
Figure out the problem yet? I picked up a 99 venture 600 triple that had thesame problems. It would backfire at low speed and sound like it was loading up. Cleaned the carbs and problem was still there. Replaced stator and still no fix. Took the carbs off again the same day and bam! Pilot jets were all plugged again literally after 30 secs of running. Cleaned them again, added a fuel filter right before fuel pump, there's a good spot to put one and airbox doesn't interfere. Anyway runs good now, that loading up and backfire were from lean condition due to pilots being clogged. Seemed like an electronical problem but wasnt. I would check carbs again!!!
 
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