SX Viper TM33 Carbs - Rebuild Jetting Questions

totallyamaha.net

1999 vmax 500 - seems like its missing at lower rpm and getting 4 mpg

This sled has 4400 miles on it and it's super clean. I am at a loss as to why it runs so crappy. Any thoughts? It will still pull 8100 rpms and makes all the right noises at higher rpm - just not good at all down low. Plugs are black. Starts up and idles fine. Kinda sounds funny at idle...
totallyamaha.net totallyamaha.net
This thread too. I'm not suggesting you need these, it's just something to be aware of.
However, depending on miles, there will be wear which means moving the needle clip around won't really matter much.
 
with the milage you have stated, you just need to move the washers from the botttom to the top to pull the needle out farther to eliminate the mid range lean issue. brother did it to his 02 viper after it blew up and did it to my dad's 05 sx venture 700 when he got it. dads has 11000 km on it with no issues.

on re reading, with the mbrp can, you will need to get it ceramic coated or use header wrap on it to keep the can hot. brother ran one for a few years on his 02 and kept getting inconsistant rpm on long lake pulls. what he found was that it would tac full rpm with the can hot from running in the trails. once it started screaming across the lake, the can would cool off and it would not pull the rpm until the can warmed up again. wrapped it with header wrap and it would as consistant as stock can on same runs. running stock can, no issues on same type of riding. jetting was good with mbrp as with stock can.
 
Let's have a pic of the needles ....if you feel they are "worn" replace them . Set your needles on the #2 setting with the two shims below the clip cowboy and adjust your pilot screw 1 1/2 to 1 3/4 turns out and report back.
 
Maim said:
with the milage you have stated, you just need to move the washers from the botttom to the top to pull the needle out farther to eliminate the mid range lean issue. brother did it to his 02 viper after it blew up and did it to my dad's 05 sx venture 700 when he got it. dads has 11000 km on it with no issues.

on re reading, with the mbrp can, you will need to get it ceramic coated or use header wrap on it to keep the can hot. brother ran one for a few years on his 02 and kept getting inconsistant rpm on long lake pulls. what he found was that it would tac full rpm with the can hot from running in the trails. once it started screaming across the lake, the can would cool off and it would not pull the rpm until the can warmed up again. wrapped it with header wrap and it would as consistant as stock can on same runs. running stock can, no issues on same type of riding. jetting was good with mbrp as with stock can.
Click to expand...
Also make damn sure your float height is correct
 
GasCans said:
I picked up an assortment of main jets, gaskets and fuel line hose yesterday. Planning to open up the tops and pull the slides this morning and finish up my benchwork before putting them back in with 153.8 jetting and adding some new new fuel lines.

Where should the needles be set at?

IMG-1706.jpg
Click to expand...
 
littlejohn said:
Let's have a pic of the needles ....if you feel they are "worn" replace them . Set your needles on the #2 setting with the two shims below the clip cowboy and adjust your pilot screw 1 1/2 to 1 3/4 turns out and report back.
Click to expand...
It's not the needle that wears.
 
Nitro I'm sorry but I have dealer level manuals and I'm just not finding these specs . What page of manual ?
 
Keeping this thread on topic.....

Just got done cleaning the first of three carbs. Needles look good and clip is on the middle (third position) with 2 plastic washers below it. I'm installing new 153.8 main jets as shown below. Are these good to go back in on position 3 with washers under it as shown?

Position.jpg


Parts.jpg

Needle.jpg
 
GasCans said:
Keeping this thread on topic.....

Just got done cleaning the first of three carbs. Needles look good and clip is on the middle (third position) with 2 plastic washers below it. I'm installing new 153.8 main jets as shown below. Are these good to go back in on position 3 with washers under it as shown?

Position.jpg


Parts.jpg

Needle.jpg
Click to expand...
You have it correct.
 
littlejohn said:
Nitro I'm sorry but I have dealer level manuals and I'm just not finding these specs . What page of manual ?
Click to expand...
Page 2-9 of the book I mentioned. It says Power Launch'02 on the cover also.
Don't matter anyway, the information has been provided.
 
This was a lot of fun guys. Thank you for all the additional info. My buddy Darryl sent me the maintenance specification page (65) with all the jetting variations based on elevations and temps which was handy. I took the carbs off the rack, cleaned the entire body, slides and all parts thoroughly. Have 2 left to complete tomorrow and then I'm onto greasing the sled and changing out the chain case oil. Taught my 2 boys as we went along tonight. They enjoyed it also. :-)

YFRI4237.jpg


IMG-1758.jpg


IMG-1756.jpg
 
You must log in or register to reply here.


Back
Top