Strange Behavior

[redsoxrule]

1994 Vmax 600 ST...recently went up to Tug Hill and the sled ran like crap. Wouldn't go over 50 and struggling to get there. Seemed OK up to around 35, not quite as peppy as usual. Last change was a local dealer telling me I should be running 93 instead of 87, so I filled the tank with 93 before hitting the road. Pulled the plugs after a few trails at the Hill and they were fouled completely. When I got home I drained the gas and put 87 in (a little 93 left), and it seemed a lot better. Plugs looked better. Odd thing is when I had it on the stand, it reved well and sounded good, got up to 90-100 MPH on the stand, the motor sounded good, track spun solid. Question is should I be looking at ignition/fuel delivery or the clutch/drivetrain as a possible area of concern. Is the "stand test" a valid one to differentiate between ignition/fuel and clutch problems, or could it just be the 93 gas causing the problem. Also at home had a small run in with a tree, left front end and shock tube damaged. The tube has a tear in it now, can that be replaced seperately, or do you need the entire shock assembly. Hasn't been ridden since the small tree got in the way, so I believe the shock is still fine, the ride back from the incident didn't show any steering or control problems, the shocks both responded to the skis. Frame seems fine, although the front bumper got bent. Thanks in advance.

 

[hereismylife]

when did you last clean the carbs? Is it running rich?

 

[redsoxrule]

I haven't cleaned the carbs yet..just got the sled, wanted to see how it runs. As i said though, the plugs looked good after running 87 for about 20 miles, it ran great on the stand. I had read somewhere that if it runs good on the stand but not the trail it may point to clutch vs fuel/ignition. I do plan on a complete tune up in the summer.

 

[blue missile]

the 93 octane should only make it run better it will burn better. maybe the fuel was of poor quality water or old, i had heard the gasoline should only be stored for something like 3 mos because it's octane will diminish? is that true anyone with some input.

 

[yamaholic22]

get in there and clean those carbs and see what you find

 

[FuzzButt]

See http://auto.howstuffworks.com/question90.htm for an Octane primer. This is what the FTC says about Gasoline http://www.ftc.gov/bcp/conline/pubs/autos/octane.htm About octane is in the middle of the article. The best so far is here http://www.straightdope.com/columns/041008.html kind of easier to read too.

Basically unless it is called for 92 octane is wasting your money. It does not burn better only resists combustion due to compression longer.

 

[SNOWRULES]

i had the same problem with my 94 v max 600 it turned out to be the primary clutch bushings they were badly worn and binding. ran good on the stand but with me on it under load on the trail it ran like crap so you might want to check that. pull the clutch and take the spring cap off and spring out then try rocking the sliding sheave back and forth and see if there is alot of play then slide the cap back on without the spring and do the same and see how much play is in there just may be your problem. also i set my needle clips a half position leaner and it helped alot still ran really rich thiose motors just run pig rich but i found it did help. hope you get her fixed up oh and cleaning your carbe would be a good plan too.

 

[daman]

'94 VM's had a Thin HG back then with 150+ psi. stock.. you can run a little
higher grade gas like 89 or 92 won't hurt should help..sounds like carb probs.

Yes the strut tower can be replaced only..there like $50 i think....

Beeing damaged like that it does effect the shock performance,,should be fixed