November 28, 1997
Dear Ralph
I’ve heard that using the NGK type “V” plugs are the best for checking jetting. What about it?
When using the “V” plugs, the tip of the electrode is an excellent indicator of the fuel air mix. The tip should have a silver appearance about 1/3 of the way down. If no silver is showing, or silver shows only at the edge of the tip, it’s running rich, silver past the 1/3 point means it’s lean. The only real way to know how safe you are at partial throttle is to be watching the EGT. You could make a mid range (like half throttle) run for a 1/2 mile and hit the kill switch while holding the throttle constant. When she stops pull the plugs and see what the tips look like. Do the same on a lake with a WOT run for 1/2 mile or more, hit the kill switch while keeping the throttle position constant. This is the most accurate way to check plugs if you don’t have an EGT. I am convinced an EGT set up is the way to go for those looking for that edge. Good probes with an analog gauge work fine, but the digital units provide the best accuracy and are easier to read.
November 28, 1997
Dear Ralph,
If I wanted to reduce slide friction in all snow conditions, should I get Teflon or graphite sliders for my sled (1997 MX Z-440 LC)?
1. What’s the difference between Teflon or graphite?
2. Will one last longer than the other?
3. Are they really worth the money?
4. Is there a real noticeable difference?
Jason Richard
1. There are basically two different types of “friction reducing slides” available – we’re going to call them “blended” and ” insert” slides. The “super slippery” and “graphite” slides are blended, where additional materials are blended into the UHMW plastic to reduce the friction characteristics of the slides. They truly do reduce the friction, but provide only slight increases in longevity compared to standard slides.
Insert slides are a standard slide that has a slot machined down the center where a piece of solid teflon material is inserted. This not only provides a reduction in friction, but also provides a huge increase in longevity – in the right conditions. Normal UHMW has a melting temperature of about 300-325 degrees, where Teflon begins to melt up around 700 degrees. The Teflon also has a tendency to “coat” the metal track clips, providing additional friction reduction.
2. Insert type slides last longer than blended types.
3. Blended types should be worth a bit more than a standard slide due to the friction reduction – the insert types should be worth even more due to friction reduction AND substantially longer life.
4. Depending on the conditions you ride in, and the suspension type, the difference can be major, or not even noticeable. If you always ride in conditions where lubrication is never an issue, then you may never realize any benefits. Most of us ride on ice and frozen snow (especially after warm afternoons) and this is when you’ll really notice the difference.
November 28, 1997
Dear Ralph,
I ‘m having trouble setting up the rear suspension on my ’97 ZR 580. The problem I’m having is bottoming when coming off jumps and at the bottom of drop offs and hills. It is fine on small whoops but terrible otherwise. I have tried all preload settings and have the springs set to the stiffest setting. It doesn’t kick back, just bottoms hard. I weigh 218 lbs.
Greg Bacon
The shock valving in this sled is set more for Mr. Average Trail Rider than the ZRs used to be. And, Mr. Average Trail Rider weighs more like 170 -190 pounds. I have the same problem, and needed to revalve the shocks in the rear. Any Fox Shock rebuilder can help you do this.
November 28, 1997
Dear Ralph,
I recently picked up my new Yamaha 600 XTC. I was really impressed However, one of the big things advertised about the sled was the “loads of pre-load” on the suspension. The problem is; there is no wrench in the tool kit to accomplish the pre-load adjustments. One person at the dealer told me that only the dealer should make the pre-load adjustment!!! (What a joke!) Someone in service told me I could ORDER the needed wrenches for $60! What is going on? Did Yamaha market their “premium ride” sled with “loads of suspension pre-load” that the consumer can’t adjust on his own?!!
David Stradtman
Stillwater, Minnesota
There are really two separate adjustments that can accomplish “effective” preload adjustment of this rear suspension. The easy one is the three position slotted adjustment at the front mounting point of the rear shock. By loosening the bolt and moving it to a different position you change the effective pre-load, but more accurately you are changing the shock leverage ratio. This is the easy one. The true pre-load adjustment is the spring length on the shock, and Yes, this does require special wrenches. But, you only have to mess with this one if the slotted adjustment doesn’t do the job. The dealer was simply getting too technical with you. He should have explained the slotted adjustment, as this is the one being touted as being so easy to adjust.
November 28, 1997
Dear Ralph,
I was reading a “Dear Ralph” question about blowing head gaskets on an XLT. I had the same problem with my 95 XLT 600. The problem is a separation between the cylinder liner and the block casting on the exhaust sides of the mag and pto cylinders. We sent the cylinders to SLP and had them machine .007″ off the surface. Polaris has stated they had this problem on others, too. Just thought you would like to know.
Ed “Turbo” Anderson
Thanks for the info!
November 28, 1997
Dear Ralph,
A few of us noticed that Polaris has upgraded (increased the size) of the crank bearing on the monoblock XLT engine and has added an oiling line to that bearing. One of our group is bummed that his XLT Limited SP doesn’t have the “XC Motor” which he claims is this updated crank bearing/oil lined engine. Further, another of our group found his XLT SPs does not have the oiling line. It appears some have them and some don’t. This sounds real fishy to me. Why do they need direct oiling of their crank bearings when most of the other MFGs don’t?
There are actually several different versions of what we all refer to as the “XLT engine”, or “600cc monoblock”. The ’97 XC 600 uses a unique PL08 cylinder block, while the XLT Specials use a PL04 block, and the rest of the XLTs use a PL03 block. All indicating a different level of port timing. The PL08 was the first version to use the extra PTO bearing oiler – the logic being that this was the most likely one to have pipes installed and be spinning at a higher RPM – nothing more.
November 28, 1997
Dear Ralph,
Can any more power be had from the ’97 ZR-440? Is it only a different spread of power that can be had from various pipes, etc. or can we get more power?
Jeff Piccolo
Plymouth, CT.
Snowmobiling – The only winter progression for a bored & battered Dirt Biker!
Jeff,
There is always more to be had – does it need to stay stock for a racing class, or can we go nuts with it ?
#1. Blueprint the engine
#2. Bigger carbs, reeds, twin pipes.
#3. Bolt on a turbo.
#4. The best idea is to wait and see what goodies come out just for it.
November 28, 1997
Dear Ralph,
I have a stock 1994 Yamaha V-Max 600 and about $500-$600 dollars to spend. What do you recommend for the best performance gains for this kind of money?
Brian M. Polka
You need to define “performance” before we can make recommendations. Do
you want 1000 ft acceleration, powder climbing, average trail riding,
lake top speed?? The best way to spend your cash depends on your application. Personally, I’d go with carb boring, clutching, and gearing – all which can be done for about $500-$600.
November 28, 1997
Dear Ralph,
Your Oct/Nov ’96 issue illustrates one of the major problems in educating snowmobilers: CONFLICTING INFORMATION! On pages 66 & 67 Jim Shepard and Bill Westhoff tell us that a more aggressive (greater angle) secondary clutch cam will increase the squeeze on the belt.
This is contrary to the advice that Olav Aaen has been giving us for years: “The smaller the angle, the more torque feedback and higher belt pressure you get”. (Page 16 of Olav Aaen’s Clutch Tuning Handbook).
How are people supposed to learn from such conflicting info?
Gerry Smerchanski
Teulon, MB
This is a tricky one – you’re assuming that “increase the squeeze on the belt” is the same as “higher belt pressure”. What I believe Jim Shepard was referring to was that when you use a more aggressive helix is that the drive clutch is allowed to increase its squeeze on the belt. Aaen is also right in saying that a smaller angle helix increases the belt pressure in the secondary.
November 28, 1997
Dear Ralph
I own a ’97 EXT 580 EFI and was wondering if you can give me some tips on what I can do to modify my sled to get more power. Is it worth playing around with the EFI or should I just buy a bigger sled?
Terry Mee
Your best option would be to simply install an aftermarket EFI chip that has a more aggressive fuel map to make more power (about 5 hp). Arctic Cat performance shops like Black Magic and D&D Cycles offer such chips. However, you’ll have to watch your fuel supply as some the “margin of safety” is used up in creating the extra power. Some master tuners have experimented with using an adjustable pressure regulator for the EFI fuel rail. The theory is that minor differences in the fuel pressure regulators allow some room for performance gains. By monitoring the exhaust gas temperature you can reduce the pressure in the fuel rail to lean the mixture and make more power. This is more of a development tool for those who make the chips and is not for the casual tuner, but I thought you’d find it interesting.
