mxz 670 ho jaws twin pipes jetting suggestions....

[meandmyz]

hey all, i am new here and i had recently purchased a few sled for a steal...one being a 99 mxz ho th for 500 bucks but needed to be rebuilt wich i have now done and am getting 130 psi aside, i have a set of twin jaws pipes and now need to do the tuning and i am unsure where to start, i have cleaned the carbs up and tried to set it up to the stock specs but that bis just not cutting it, it won't even idle to warm up...if i prime the hell out of it i can get it to start and run for about 15-20 seconds if i play with the throttle i can keep it running and i can rev it up but then it just dies out and when i pull the plugs out they are usually wet....or black....where do i start...i am confused, i build fast cars and big trucks and am having a real hard time figuring out this 2 stroke carb tuning....any advice would be great.....thanks in advance

 

[magnet]

are your needle and seats closing completly? even if your jets are way to big it should still idle fine.

 

[Deano670]

Has anybody had the rotary valve off this engine????

 

[modz]

First what I would do is make sure to put NEW plugs in, possible that they are fouled up and your getting WEAK spark, I think your jets are not the problem, While running check if fuel is coming out of carb vents, This would indicate needles not seating properly, 130 psi compression sounds pretty good. What engine is in your sled?

 

[rustyrocket]

First what I would do is make sure to put NEW plugs in, possible that they are fouled up and your getting WEAK spark, I think your jets are not the problem, While running check if fuel is coming out of carb vents, This would indicate needles not seating properly, 130 psi compression sounds pretty good. What engine is in your sled?

Have you ever thought about putting it back to stock . They run just fine in that form , no more guess work ? Just a thought .

 

[j.c.higgins]

How about a carb synchronization. Has that been done? Have a look at your cut aways when pulling the throttle to make sure they are lifting at the same time.

 

[Ancient Sledder]

Maybe the fuel pump is not working or the pulse line is off ???

 

[Pappillion]

I had the same symptom in the same sled. One of the lock washers holding the carb needle in place had broke causing the needle to fall into the bottom of the carb bowl. Unscrew the top of the carb and check to see if the needle is in place.

It took me a couple of days to figure out. And yes, I feld really dumb when I noticed it.