vmax 600 stuttering

xboxwizard2003

xboxwizard2003

New member
Joined
Dec 15, 2005
Messages
13
Age
39
Location
Marlette, MI
Hi
i have a 1998 vmax 600 twin
it will run good up to 4000 rpms
from 4000-6000 it stutters, hesitates, has very little power.
then at 6000 it just takes off and runs good
i just cleaned carbs and blew out the jets.
any ideas.
i have the jet sizes wrote down out in my shop and i will go get them and post later.

Thanks
 
it might be the tors but i dont think you would be able to get over 4 grand when the tors is working check your clutch over it could be that
 
yes it is a stock clutch.
it will run at 4000 rpms and do about 20 no problem motor runs nice and smooth. as soon as i squeeze the throttle more it will stutter and run rough, it will take off as soon as it hits 6000 rpms i took the carbs off and cleaned the pilot jet but it made very little difference.

Here is the jet sizes.
151.3 main jet
45 pilot jet
0.8 air jet
fuel screws are 1.5 turns out

these are the numbers stamped on the jets.
any help is appreciated because i have no idea what i am doing when it comes to jetting.
thanks
 
Sounds like your needle jets are running a bit rich, ...raise your needle jet clip 1 notch.
 
my wifes 94 vmax 600 was doing the same thing last year.
It would start,run and idle great.
Between about 3000-5000 it would be crap! Cleaned carb--no difference.
Turned out that the buttons in the secondary were worn out and the helix was jamming up on the slide bushing thing in there b/c of it.
When the sled made enough power with the rpm's it would force the secondary to work.
Replaced buttons and the helix, no more problems.
Just a thought.

mul
 
the only mod i have done is the reed valve stopper notch.

i will check the secondary clutch.

when i get home from church i will see if i can raise the needle valves.


thanks
 
Yes you can, ...remove carb covers, ...remove allen key bolts using a rounded allen key, ...clamp the throttle lever and pull the needle jets out (careful not to loose any plastic washers, if any) from the needle. Always follow recommended clip position depending on your elevation, ...unless you've made intake/exhaust modifications (see tech section).
 
wow! what a difference much smoother running.
Now my sled runs much better in the midrange.
i raised the clip 1 notch. now it is in the top notch with 2 washers under it.
my needle only has 3 notches.

Is there any way to know if it is in the right notch? i dont want to wreck my engine.
Thanks for the help
 
Run your machine at midrange for a wee bit, ...abruptly shutoff machine and check spark plug colour, ...should be dark to light brown.
 
my wifes 600 xtc has the same exact problem,tried the sec.clutch off my srx to see if that was the problem,no difference,already been into the carbs ,pilot jets were fine,sled has 7000 miles and has always run fine so I ruled out carb adjustment. Decided I would pull her primary clutch off and try mine to see if that was it ( worn bushing maybe) much to my surprise when I pulled the primary off I found that the crankshaft oil seal had come apart and was rolling around on the end of the crank needless to say I think I found the problem. Her sled acts the same way the first post described will hardly run between say 4500 to 6000 then she screams. much running like this and pistons would be toast for sure. I am going to get a new seal today I hope. So I would encourage you guys to look at this seal if your sled is acting like this .You might be able to see it without pulling the primary. I'm sure glad I decided to to try my clutch on hers or I may not have found it.
 
Gees man! . I didn`t start this thread but I`m having the EXACT same problem on my friends 97 V-Max 600 SX, it idles somewhat ok, but when you give it throttle (or atleast from the rpm where primary starts to grab the belt) it bogs, doesn`t react on the throttle, but then when I give her full throttle it fly`s, at around 6000rpm, just like you say.

I tried spraying som CRC 5-56 on the PTO crank seal but there was no difference on the engine, engine was pretty cold and I did not rew it while I did it... should I?.
 
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