rta60460

I have a 95 vmax 500 and it starts right up but as soon as it gets warm it loses power bogs and dies almost like its out of gas...a friend of mine swears up n down its the cdi box.....does this sound right? any other ideas? the sled ran great then one heavy snowfall at the end of the year it started doing this...thanks for any ideas...oh yea I changed the coil and it didn't help..

Yamaha440

It's not the CDI Box. It's one of the coils, when they go bad sometimes they will "crap out" when it warms up. It can be the external, or the coils on the stator. To check the coils, you will need a quality multimeter that can test in ohms and the factory spec in the service manual.

__________________
My Current Sled:
1997 Yamaha Vmax XTC 600 Twin ER 6290 MI - Stock... for now...

Old Iron:
1979 Yamaha Exciter 440 6042 MI (9825 KM)
1979 Yamaha Exciter 440 7,000 MI (11266 KM)

WAKE-UP AND SMELL THE TWO STROKE

yamadad4

+1 on not being the cdi. some more description of the symptoms may help narrow down the root cause.

does the problem occurs after riding or if it sits and warms up? stator issues were a rarity on the 95's, although still a possibility.

fuel pump, sticking clutches, crank seals, deteriorated fuel and impulse lines, kinked/plugged vent lines or even reeds, down to plugged exhaust and a few other possibilities.

is the problem intermittent or constant? have you fired the sled up this season?

rta60460

well I'm back at it tryin to fix this sled before the season...I changed the coil and the cdi and its still not running right...it acts like it wants to go then it will finally move then it bogs out and wont go but runs and sometimes backfires pretty loud

smokingcrater

Sounds A LOT like a failing TORS system.

__________________
1) 2000 Arctic cat ZR 700, which now thinks it is a 2001 ZR 600 EFI APV w/136" ripsaw. (for sale!)
2) 1995 Yamaha VMAX 600, which now thinks it is a Polaris! (Polaris x10 suspension, Polaris P85 clutch) (for sale!)
3) 2004 Yamaha Warrior
4) 2006 Yamaha Nytro

rta60460

Yea I was thinking that to after reading a bunch of stuff...I'll try bypassing it

kccats

The backfire could be the reeds too?

rta60460

It all started i got stuck in really deep snow and was giving it hell tryin to get out..now i cant drive it, it starts right of n revs fine but soon as its warm enough to ride it wont pull itself and it want to bog down n tries to die andsometimes backfires real loud

rta60460

I've changed the cdi and the coil and i've bypassed the tors and still doing it...wondering if its the stator just hate to keep puttin money in it and not fixing.. I checked compression and they were both pretty much the same maybe 1 or 2 psi different, think they were like 117 or 121 cant remember its been awhile since i checked it

yamadad4

does your temp light function? could be your waterpump drive belt is worn or loose and your creating an overheat condition.

from there, i would test the stator as soon as it acts up. tough call from the keyboard.

Grudman

rta where you at in ill if your close by i could buy and take a look. SOunds more like a fuel vapor lock issue.

__________________
1997 Arctic Cat 580 Efi Deluxe

Grudman

rta60460

My temp light works and hasnt came on at all, also when it first hapened i put my spare belt in cuz i thought maybe it was the belt but same thing

rta60460

I'm in odell, its like right in the middle of joliet and bloomington on I55....40min south of joliet

yamadad4

you have some odd symptons happening so lets back track and rule out a couple items.

since you got stuck and perhaps smoked the belt, is there excessive belt residue on the clutches? like lots of black showing? you said you changed the belt, so where is the belt riding in relation to the top of the sheaves on the secondary?

with the exception of the backfire, it almost sounds like a stuck clutch. like the belt is sitting low in the secondary being the equivalent of trying to drive off in your truck in third gear. so in theory your loading the engine hard trying to get the sled to move. easy to rule this out with a visual.

from there, the power loss and the backfire would be consistent with a failing stator. wouldnt have any direct relation with the stuck scenario. when they start to go, they just do. could be just coincidental. problem with your description is they will test okay at room temp but the engine heat will cause the any breakdown in the wiring to rear its ugly head.

i may have a stator you could use for testing purposes if the right conditions were met.

joshkidner

i use engine cleaner (some heavy duty cleaner, will burn your nose) to get burnt belt off. i spray it on a cloth and simlpy wipe it away. becareful where you spray it. it wil ruin rubber lol

rta60460

This sounds like a good possibilty with the belt .. I hope its that since it would be an easy fix, i will check it this weekend cuz i work from before the sun comes up till after the sun goes down mon-fri so i don't do much thru the week lol.. I'll give u an update either way this weekend... Thank you

yamadad4

it would be indeed a relief if it was as simple as that. good luck!