85 Vmax 540 running bad....Help!!

zeroburn · Post by **zeroburn** » Wed Jan 02, 2008 5:10 pm

Hi everyone im new to this site and my vmax. I have an 85 vmax with the 540 in it. I bought this from a friend who put it together from a pile of parts from someone who had taken it down to the frame. Any way it was running ok last year execpt for some minor secondary clutch issues but i got that fiqured out. Now this year i wasnt going to ride the vmax much just to keep it in decent shape but i snaped the crank in the xcr 440 and have not been able to find a crank for it yet. On to the issue with the vmax, lol. It will start and just idle if i try to pick it up off an idle it dies i tried different fule pumps just to see it that did anything same issue, now i think it could be an ingintion issue but since these sleds are so complex compared to others i have no idea what is going on. When it does get running so that it will move its an animal for about 20 -30 seconds then falls on its face. I dont know how else to describe the issue. Any help would be most greatfull.

nate

opsled · Post by **opsled** » Wed Jan 02, 2008 10:30 pm

Clean your carbs.

opsled

zeroburn · Post by **zeroburn** » Fri Jan 04, 2008 1:42 pm

Ok carbs are clean and still have the same issue. Any other ideas?

Donnie · Post by **Donnie** » Sat Jan 05, 2008 12:05 am

When the sled starts to fall on its face, crack open your choke lever which will richen the mixture.

If the sled picks back up, then it is leaning out on the top end. This could be a main jet still clogged or just too small, air getting into the fuel from a cracked hose, float set too high and not getting enough gas into the carbs, or fuel pump failure starving the carbs.

If it stumbles even worse with the choke open, then it is too rich and flooding the engine on top end. This could be caused from the jets being too large or restriction in the exhaust.

I have also seen spark plugs crap out and not fire under high RPM's.

Good Luck

Donnie