99 vmax 600 sx red head help!!

hessracing

Member
Joined
Dec 10, 2009
Messages
315
Age
35
Location
Iron Mountain Michigan
Hey Guys. My buddy bought this worn out 99 V-max 600 sx and guess who's stuck trying to fix it! yeah... so i'm having a few problems. The damn thing doesn't run right.

It will start up and go but under a load. It is strong sometimes and the other times is weak. I noticed the belt is sitting low so i added shims and now the sheeves are touching each other- I don't think you can get it any tighter. i tried 3 different belts i have at my house. One is new and it still sits low.
Is something else worn out the helix bumpers? also it is loading up on the bottom end and back firing. I don't know how old the gas is so i added some isopropyl to it. i did clean the carbs on it when it first came to me.
One of the fuel screws is stuck and i almost broke the tip of my screw driver off trying to break it free. I'm feeling like this is my problem. the plugs are new and all are wet when they come out. it does not have the center of the air box- it didn't come with it. any input is appreciated... thanks guys!
 

well I took it all apart again and worked my *** off but i got the fuel screws out and destroyed 2 of them getting them out!! I have no idea where they were set at but when the new ones come in i can set them where they should be! I pulled the reeds out they are all in great shape so i can rule those out, i do not have a compression gauge so no clue there but thats a good idea! ill keep everyone posted when parts come in!
 
I got the clutching figured out changed the spring and that did it. Now to the Carbs was able to extract the fuel screws i bought 3 new ones put them in the carbs are clean as can be! fuel screws were set to 2 turns out like factory says i get a back fire when slowing down and getting going again still i tried the carbs at 2 1/4 turns and it still has a back fire , this sled does not have the air box foam cover and the previous owner drilled the can i found out do you think turn out to 2 1/2 turns?
 
Make sure your float height is correct. also make sure your needle and seat are ok. carb synch ect ect.
 
what do you guys think about raising the needles a notch? float height & needle and seat are correct and carbs are all synced perfect due to being on the rack
 
Most 600 and 700 triples run much better with the C clips raised one notch on the needles. (4th notch from the bottom)
 
carb synch can be out. being on a rack makes no difference. Not that being out of synch will make a backfire. But making sure all systems are correct helps trouble shoot.
DOUBLE check float height. fuel screws at 1.5. keep in mind needles are going to change jetting more in the mid range than at idle and say slightly off idle.
 


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