Dear Ralph:
There must be an answer to my problem and hope you can point me in the right direction. I own a 1996 Yamaha V-Max 600. The sled runs super and is a real looker. My problem is after a few miles of riding, the back of my helmet, my coat, and the back of the sled is covered with snow. After about 45 minutes the snow is starting to melt and my back is wet and starting to get very cold not to mention that the tail light is completely covered over. With this in mind, is there an easy fix like an after market snow flap that is stiffer or wider than the Yamaha flap, or is that even the cause of the problem?

Bob Schrieber

Don’t all sleds do this to some extent depending on the conditions? Yet, in all our years of riding all brands of sleds side by side for thousands of miles, we can testify that Yamahas have had this tendency more often than the other brands, especially the pre ’97 models. Those years tended to have the tunnel taper quicker at the rear. Aftermarket skirts installed in this “gap” between the tunnel and snow flap will help reduce this tendency.

Dear Ralph:
I have a ’98 ZL 500 that runs great. It’s fast for a 500, and can really move out of the corners with good weight transfer to the track. I like the suspension, but I have one problem. I weigh about 230 pounds and I’m a fairly aggressive rider. I like to take jumps and blast through the moguls. In short, the rear suspension bottoms out and all my dealer will say is “Buy stiffer springs and have me install them”, but I have seen people move the position of the rear arm connection to the rails to stiffen the suspension. My dealer’s response to this was, “This changes the ratios of the Torque Sensing Link and breaks things.” To me, it doesn’t seem like Cat would put five different mounting holes in the rails if you couldn’t move the arm without doing damage. Any help would be appreciated, as I’m tired of bottoming out.

You are correct, the five mounting holes are there for suspension adjustment. The only Cat you can’t do this on is a ’98 Panther. By moving the mount to the rear you will stiffen the suspension, by moving it forward you will soften the suspension. This will also help to keep the skis on the ground. Your dealer was confusing this with the different upper mounting holes for the suspension, which should not be used. I would try moving the mount back and work with the spring pre-load settings. Installing stiffer springs is always an option if you need to.

Dear Ralph:
My question is about horsepower! I am one of many who have been up to the big bores and are heading back down. I came to the realization last season that I am getting old. I’ve run my ’88 650 Wildcat for many years and loved it. I purchased a ’91 700 in my search for lighter and more trailable manners. This past season I broke down and bought a ZR 600. Although I’m not overly concerned about total horsepower, I am curious as to how they all compare.

Kevin Connell
Princeton, Illinois

The ’88 650 Wildcat produced 105 hp at 8000 rpm, and the ’91 Wildcat 700 was up to 113 hp at 8000 rpm. The ’98 ZR 600 was said to be producing 105 hp, but most of the dyno numbers we’ve seen have been in the 98-101 range at a higher RPM of 8300-8400. What is more important is the horsepower to weight ratios of these sleds. Even though the smaller displacement ZR 600 has less horsepower, it is so much lighter that it will outrun stock Wildcats.

Dear Ralph:
I have a 1997 Polaris Indy XC 700. I had the sled clutched before I picked it up. When I ran it against my friend’s Ultra I wasn’t very impressed. Next, I replaced the stock silencer with an aftermarket silencer, still using the stock pipe. Since the stock jets are typically a few sizes bigger than needed, I was wondering if I have to make any jetting changes? P.S. I now beat the Ultra by 4 sled lengths in an 1/8 mile on the grass!

Andy Vollert
Stevens Point, WI

In most cases when you replace the stock silencer with an aftermarket pipe you are reducing the outlet pressure which will make the engine breathe slightly better. If your engine is going to be pumping slightly more air, then it will need slightly more fuel to maintain the air/fuel ratio. Most silencer makers will tell you the net effect of installing a silencer is about 1/2 of a jet size, not enough to worry about. If you still have stock jetting in the sled, then you should be just fine. For an engine that is already jetted to the edge, then the addition of a different silencer could be just enough to make the difference.
Our experience has been that a different silencer, added to a stock machine with no other changes, is good for only one percent or two of a power increase (not much). The real benefit from a different silencer is to reduce the weight, many times approaching ten pounds. The problem is that many silencers are so much louder than stock they are illegal for use on public lands & trails. The leading silencer manufacturers have learned that you do not have to make your machine louder to make power, quite the contrary. Quiet silencers are now able to make as much, and more power than the loud pipes.

Dear Ralph:
Last year I purchased a new Yamaha V-Max 600 XTC with the factory installed electric start and reverse. My question concerns the reverse gear. I find that sometimes when I try to engage the reverse gear, it will not go into gear. This is with the engine at or near idle speed. I find that if I move forward an inch or so, or turn off the engine and restart it, it will engage. What causes this? Is this normal? I don’t remember my ’95 V-Max 600 (which also had electric start and reverse) doing this.

Skip Wareham
Hopkinton, NH

Are we supposed to believe that you’ve never had this problem with a car, truck, or four wheeler before, let alone a snowmobile? Or, have you been driving automatic transmissions all of your life? What is happening is that at the moment you attempt to engage the reverse gear is that the reverse mechanism is not “meshed” properly; the cogs on the gears just don’t line up quite right. By moving or stopping and restarting the engine, you have rotated some of the gears and now they line up properly, allowing you to engage the reverse gear. This will happen on occasion on just about every shifter vehicle that I’ve ever used so, “Yes”, I would consider it to be normal.

Dear Ralph:
What do you think of using Automatic Transmission Fluid in the chaincase?

Art Rodriguez
Minneapolis, MN

Why would you want to use ATF in the chaincase? I’m assuming you think ATF will provide enough lubrication for the chaincase with much less resistance, which will translate into less loss of horsepower. The logic is to reduce the rolling resistance of the vehicle, allowing more of the power produced by the engine to make it down to the track, minimizing the power loss due to friction. As the temperatures get colder, this would become more evident.
I don’t think ATF would provide adequate lubrication. I would be more interested in long term durability. My recommendation is to run a 100% synthetic chaincase lube. This will maintain superior lubrication, keep the components running cool, and will not turn into “tar” at extremely low temps. I’ve even known racers to remove all of the bearings from the drive line and rear suspension, clean out all of the petroleum based lubricant and re-pack them with a synthetic grease for less friction and loss of power.

Dear Ralph:
I am slowly learning about the potential problems with “inadequate” gasoline, i.e. low octane, moisture, etc. I own a 1997 Ultra with a Legend Trail Dominator Kit installed. Are there any disadvantages of using octane boosters when I fill up with 91 octane gas? Are moisture absorbers in the gas tank of any value? Is one of the above better than the other as a precaution to engine meltdown? I do not want to have to install EGT sensors and I do not have access to racing fuel.

Marvin Werbitt
Montreal, Canada

There are no real disadvantages of running octane booster with 91 octane fuel, just follow the directions of the product and realize that you will only raise the octane by 2-3 points. Adding more booster than the directions say will not help. In tank moisture absorbers are of value if there is water present in the fuel, but if you’re running ethanol blended fuel it is less of an issue as the ethanol will remove the water. Many 91 octane pump fuels already have ethanol in them. Which is a better precaution to prevent engine meltdown? Personally, I would run the recommended octane fuel and add boost if ever in question of the fuel quality. More important will be the proper jetting to avoid trouble.

Dear Ralph:
I believe there is one important factor affecting compression that you neglected to mention in your Winter Issue “Dear Ralph” column: ALTITUDE. Here in Idaho Falls, (4600 ft above sea level) we get compression numbers approximately 20% less than the sea level numbers published in the shop manuals. This is because we have less pressure in the cylinder before compression begins. At sea level the absolute pressure is 14.7 psi where here it is on the order of 12.4 psi. Assuming isentropic compression (no heat transfer to or from the cylinder walls) of an ideal engine, the final absolute pressure in the cylinder will be some factor mutiplied by the initial absolute pressure. Therefore your final absolute compression number will be proportional to your initial absolute pressure. To find the equivalent compression gauge reading at altitude one must know the local atmospheric pressure and make compression gauge corrections according to the following relationship: “Absolute pressure = gauge pressure + local atmospheric pressure”. Doing the math on this indicates that a sea level compression value of 120 psi ‘gauge pressure’ will be equivalent to a 5000 ft elevation value of approximately 100 psi ‘gauge pressure’. As a rule of thumb the shop manual compression value should be reduced by about 1% for every 250 ft above sea level. Perhaps this should be mentioned in a future column before some hapless soul in Denver tears down their ‘worn out’ 100 psi compression engine.

Ted R. Reed
Idaho Falls, ID

Thanks for pointing out such accurate, very useful information.

Dear Ralph:
Just read your column about a problem a guy was having with a secondary clutch springs that was too stiff for the sled it was installed on. It was very informative and solved a problem that I have been having with my wife’s sled (Indy 440) for the last year (i.e.. no top end). My wife is an aggressive rider but small in stature and weight. The standard 440 liquid was a great machine for her except the standard clutching which was extremely soft. What I did was take the Erlandson springs that I had from my XLT and installed in her sled. The primary was white and the secondary was yellow. As well, I used a Polaris T1 triangle helix. This setup gave a maximum rpm of @ 7900. The big disappointment was that we could only get 70 mph top end. The clutches were obviously not shifting out fully. After reading your article I pulled the Yellow Erlandson secondary out and reinstalled the stock red spring in the third hole. Just like magic the sled ran 85 mph on the speedo with me on it (@ 214 lbs) and was still climbing slowly when I ran out of room. Wow, what a difference! My question to you is this. Would I be better off installing a Polaris blue or almond/yellow primary spring? I am wondering if I am slightly above the powerband at 7900 rpm. I believe this engine should rev out at @7750. Any suggestions would be appreciated. Maybe I should leave well enough alone!!!

Peter Young

Perhaps the first and most important lesson you learned is that your 440 does not make as much horsepower as your XLT, and that springs that may work splendid for the XLT are going to be too stiff for the 440. If you can get that 440 to show 85 mph on the speedo with your 214 pound butt on it, leave it alone!

If you are happy with the engagement RPM of the 440, and once the sled shifts out it runs at a stable RPM then all you need to do is install slightly heavier flyweights to get the shift RPM to drop from the current 7900 RPM down to 7750. Looking at dyno numbers, the Polaris 440 is pretty flat from 7500 to 7750 RPM, so I agree that 7750 should be your target. The Polaris almond yellow is also a pretty stiff spring, and you’ll likely find that it wouldn’t allow your 440 to shift all the way out. The Polaris blue might even be a bit stiff for your 440.