1992 VMax-4 just got it and have some questions

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vincentblackshawdow

New member
New to sleds and the site. Just picked up a pretty clean 1992 750 completely stock. The sled runs really nice, I have put about 50 miles on it. Was running about 75mph and teh belt just blew. I have been reading some of the posts, and mine has the "clunking/ratcheting" sound when you take off from a stop easy. It came with a factory Yamaha service manual, and I adjusted the track per the manual. Still has the clunking when you take off slowly. Also, seems that I can only get about 80mph across the field (only about 5" of snow on bean stubble). It seems to get to 60 in a hurry, but takes a bit beyond that.

As for the belt blowing, I removed all of the cord from the clutches, and noticed the driven has some play in and out on the shaft. The bolt is tight, but seems like it would need some shims to take up the slack. It slides about 1/8-1/4". I am curious if this should be there, and if this may affect belt life with the alignment of the clutches. The sheaves seem pretty smooth, with exception to some slight, smooth groove wear on the driven face around the outer edge where the belt would ride in low ratio. The wear is smooth, but you can feel it with your fingers.

As for the clunking when you take off, I checked the track drivers, and the track teeth, and both seem to be OK (nothing appears to be worn excessively). From the rythym of the clucking, it does not feel consistent with the drive teeth on the trach, so I wondered if this could be due to the clutch, and potentially a bad belt (unfortunately I can't inspect the belt as sheis in about 500 pieces...lol). Sounds like I need a Yamaha belt, but want to make sure of the clutch alignment and sheave condition before I run a $100 belt into more pieces.

Regarding the Yamaha belts, will the 8BU belt for the 800's work on the '92 750? or do I need the 89A belt?

Sled has Champion B9OS or B9O2 plugs (can't remember). Seems to be running fine, no fouling. I have always preferred NGK plugs myself, but wanted your input on plug selection. My mnaual calls out NGK B9RES. Is this the best for a stock '92?

Sled shows 4400 miles, but I suspect it to have more, as I found a plastic punch label stuck under the hood with 15,400 on it. Either way, it doesn't appear to be worn out yet, but does need a new track. Current track is worn pretty bad, no studs, and mostly just slips....argh!

Sorry for the essay, but wanted to get most of the info out there. Any help is appreciated. I love the sled, and nothing sounds as sweet as that 4-banger giving a little "what for".
 

Forgot to mention that I checked the oil level and tension adjustment on the drive chain, and both were on spec.

Clutch engages around 3600-3800rpm, and seems to work smoothly.

From other posts I have 3been reading, seems the '92s had a few notoreous issues that were remedied in later years. What should I be looking at?
 
You should be looking for a new site lol.. J/K but i think we might be the only ones on here as i didnt get any help either. I am new to the vmax but most sleds i have owned had play in the secondary. I run br9es and it runs good. The clunk my be coming from your chain case?
 
Welcome to the site! :schild27::schild27::schild27:

1992 was the first year the Vmax-4 was built, so there were some bugs to work out. The clutches had some issues. Does your service manual have all of the technical bulletins and clutch kit sections towards the end? If not, I can post the manual I have with the bulletins. I attached one of them for the clutching and jetting. As far as the belt blowing, it's hard to say. If you just picked up the sled, it may have been sitting for who knows how long and the belt may not have been in good condition to start with. I've used Dayco Ultimax belts for years without any major problems. They're less than half the cost of a Yamaha belt and might be a good replacement until you get the clutch issue solved. Obviously, the Yamaha belt is the best choice for aggressive riding. Sounds like you need a good studded track. I blew a track on mine and rode on the new unstudded track for about 1 ride before I studded. That was too scary without studs and this much power.

The clunking could be caused by several things. Sounds like you've already checked out a few of them. I would check the speedometer housing and bearing at the end of the drive shaft. Your service manual will show you how to do that. Your drive shaft could be loose on that side. That could also cause a false speedometer reading.

I've always run NGK BR9ES plugs. That's what mine came with, it's good enough for me.

4400 miles or 15,000 miles, I wouldn't worry about that too much. These things will last forever with proper care.

Shark
 

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jjames2042 said:
You should be looking for a new site lol.. J/K but i think we might be the only ones on here as i didnt get any help either. I am new to the vmax but most sleds i have owned had play in the secondary. I run br9es and it runs good. The clunk my be coming from your chain case?
Click to expand...

jjames,
There are plenty of members on this site regularly, so I would expect both you and vincent to receive some info in good time. It is the HOLIDAYS and many members are not on as much during this time as they could be travelling. You just asked for help a couple days ago on lowering your sled, so give it some time and don't bash the site as it will not speed the process up.

As for Mark's comments above, I totally agree. Especially in regard to the speedo bearing as that was an issue with mine when it did a similar thing. But I'd put on a new belt and give it a try to start...could have been the belt all along....
 
Wasn't bashing anything.. Was just making a point not much traffic from what i see here. I did mention i was joking eh..
 
Those secondarys are also adjustable for width. The triangular washers (#12 in the blow up) are shims. It calls for two of these washers. It's been 4 years since I set mine up so I am a little foggy on how it went but I think adding washers closes the sheave and removing them opens it (could be bassakwards here). I think these shims came in the tool kit and could be added to compensate for belt wear (again foggy here) as these belts are big $ and a Max with a worn one is a real pig. I had three sleds to build my 92 out of and all were different on the # of shims in them. I don't remember what I did exactly to set mine up but the info came out of the service manual. I will say for certian that if the secondary isn't set properly (width wise, along with all other alingment issues) it can play a large roll in performance loss and belt life.

If ya got the manual check it out. May be someting to it.

Good Luck, opsled
 

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I really appreciate the info, thank you all. I have ordered a new belt and a few idler wheels for the track suspension that it needed, as well as new plastic sliders. I will check out the drive shaft bearing tomorrow and see if there is any play. I am guessing I would need to take the tension off of the track to check the play? Probably going to get a new set of NGK plugs as well, just to see how it reacts.

A little off subject, but my buddie and I bought these sleds at the same time last week (he got a '97 Ski-Doo Mach Z). Should I expect to stay side by side with his machine? His is all stock except for stingers and he has a good track with studs ( I know this is a huge part as they compare now, but am planning on a track in the near future). Also, if anyone has a lead on a decent used track with studs I would be very interested. Only ones I have seen used on eBay are marginal condition in my opinion (lots of tears, or pull-thrus on the studs).
 
Drive shaft bearing is OK.
Parts will be in tomorrow. I am now track shopping. From what I have read on the forum, it sounds like a 1" lug height is about the max that will fit. I have found a nice track on ebay with 1" lugs, but it has 1.5" woody's in it. Will that long of a stud fit in the tunnel without issues? Is there anything I can modify in the tunnel to get this to clear?
Trying to get it ready for the weekend of Jan. 15th to take to MI.
 
Does your machine still have the stock skid under the back? How many picks are in the track you are looking at? depending on the placment of them 1.5" may cause you issues with the tunnel coolers.

If the machine has a different skid under it, depending on loctaion you might clear it.... I run an X-tra 10 in my 750 and it sets down and back far enough that I have a 1" tack and 1.25" picks with plenty of extra room.

FYI I've always gone by the .25" taller than the track rule with picks not sure i'd want 1.5" with a 1" track.... just my $.02


M
 
The machine has the original skid under it. I am thinking the same thing with the 1.5" studs. Too long for me not to worry about them (idea of tearing open a cooler doesn't sound fun!) Still looking and found a decent deal on a .825" track with 1" studs. But it is claiming to be a 2.62" pitch from a SkiDoo. I was thinking the VMax-4's were 2.52" pitch. Also, this track is open every 3rd window, and clipped every 3rd. What are the thoughts on that set-up? I have no idea other than weight reduction. Does it cause any other issues?
 
You may want to inspect the chain. The chain in my '92 had two broken links when I inspected it years ago. As they are the skinny 13 link wide chain. You can upgrade to the super wide 800 chain and gears by changing to an 800 top gear spacer. Or,,,,, stick some rather coarse wet or dry to your counter top in the kitchen and sand the 92 spacer down to where the 800 chain and gears will clear. That's how I did it anyway...
 
I have an unrelated question for you mr vincentblackshawdow.

Do you have one??

A Vincent Black Shawdow???

If so I'm envious.

When I was a youngster my grandmps worked for/rode with a european bike dealer that had one set up in his living room. Awsome piece of machinery.


opsled
 
Opsled, "negative ghostrider, the pattern is full". Just appreciate the Vincent machines. I would love one as well. You may want to check out a song by the Del McCoury Band - 1952 Vincent Black Lightning.

Back to the sled at hand, I am getting less enthused the more I take appart. The entire skid/suspension is shot. Everything is totally worn out, all of the idler wheels needed new bearings, had to get 5 new wheels that the rubber came off. All shock bushings are gone. Sliders worn out. Limiting straps are about to give out. I have gotten the new parts (a lot more than I planned on spending) but think I really ended up getting shafted for the purchase price. My track will be in on Monday, so I will start putting it back together next week. I replaced the bearings on both sides of the track drive shaft as well (they were shot as well). It also appears that the drive chain case was cracked at some point and it has been TIG welded back together abound the bottom/rear of the lower gear. I amguessing that the drive chain broke at some point and got jammed around the gear?

Next item that needs attention, the thumb warmer. I am going to do some searching on here to see if there are any posts about them. Mine isn't working, and it doesn't look like they are available from Yamaha any longer.
 
I hear ya on the thumb warmer, mine does`nt work either...for the first several years I had my vmax 4, I did`nt even realize their was one on it..LOL
right off the batt, my motor was shot to hell..had to rip er down to the crank, clean it all up, get a couple cylinders replated, new pistons rings etc..cleaned every square inch of the thing..but still had`nt noticed it had a thumb warmer..LOL

anyway, just about any thumb warmer should work..just carefully pry off the old one and disconnect the wres, and throw a new one on er..
 
So just the heating element on the back of the throttle lever can be changed? How is the element attached? Glue? Clips? Where do you find new elements?
 
The parts finder on yamahasportsplaza.com says they have the throttle/thumb warmer assembly. Go here: http://www.yamahasportsplaza.com/pages/parts/viewbybrand/default.aspx Under "OEM Parts Diagrams..." select Yamaha>Snowmobile>1992 Snowmobile>Vmax-4 On the top right it says "Change Assembly". Go to Electrical 2 and it's part #16. The price is not out of line, I was paying over $50 from the dealer. I've got half a dozen throttles with burned out heater elements in the toolbox. Throttle assemblies still work fine, I keep them for spares. I haven't looked up a heater element to replace them.

Ronnie's parts finder says they still have them, too: http://216.37.204.202/hlsm_Page.htm
I assume both places still have them because when I "add to cart", it gives me a checkout price with shipping.

Shark
 
Mark, Thanks for the info on the thumb warmer, I will check them out.

Well, I just got it back together last night, and ran it around a bit (we just got about 5 inches of snow yesterday). Suspension works good, but now it seems there is an issue with the clutches/belt. I just put on a new Yamaha 8BU belt, and it seems to squeel when you first take off. Once the clutch engages completely, the noise goes away. Is this normal? or should I be checking something.

Not sure if this is related, but the clutch seems to shift too slow. The engine revs to max really quickly, and seems to hang there for a bit before it starts to shift up. Feels to me like it should be shifting quicker. Is this typically something in the driver or driven? Is it possible to improve the clutch performance just by taking them apart and cleaning/lubricating the internals? What typically wears out on them/what should I be looking for when I take them apart?
Thanks!
 
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