How-To: SkiDoo 600 HO Reed Replacement

Nov. 12, 2009 By Tony Severenuk

As a tweaker I'm always looking for ways to improve upon what the vendors have given us. Let's be honest here, they are charged with making the most money from their product lines, and as such, they aren't given a blank slate to work with. They are forced to make compromises for the corporate bottom line, and in most cases people wouldn't notice. Another consideration is they make a sled knowing that a wide variety of riders will ride it. Can we expect a sled will perform the same for a 14-year-old who just got his license and under the weight a linebacker? Of course not, so the vendors have to aim for a “middle of the road” on each of their rides. This leaves us room to customize a ride so it fits us just right.

One gain SKI-DOO gives on the 800s vs. the 600 is better reeds. In 2003, SKI-DOO had the 800 Blair Morgan Rev, and in 2004 they introduced the Rev 800 HO. The main difference between the two, performance-wise, was the intake system. The 2003 used a single reed block that has eight petals per cylinder vs. the 2004 HO has 12 per cylinder. Similar to VForce reeds, these style of reeds move half the distance of the older style so they can snap back faster, sealing the intake charge as the motor starts its intake stroke. In addition, the HO motors come with reed spacers which move the reeds back from the block, increasing the crankcase volume and giving the motor a little more bottom end.

You can easily see the difference between the 800 HO reed and the 600 HO reed.

So why buy a set of SKI-DOO reeds instead of VForce reeds? Cost. One can easily secure a set of the stock 800 HO reeds for less then $100 off eBay vs. almost $300 for VForce reeds. All one needs to install the 800 HO reeds are two new gaskets to seal the reed spacer to the block, new pilot jets (more on this later) and 12 M5 x 35mm bolts. In all honestly, if you've got the bucks to spend, I would go with a new set of VForce reeds, as they will certainly show more power gains on a dyno, but for the same coin you could have updated reeds, a clutch kit and billet goodies to dress up your ride. The choice is yours.

Removal of the Old Stuff
On a Rev, you remove the toolbox, secondary clutch and airbox. Next you disconnect the throttle and choke cables from the carbs and the coolant hoses that run through them. Then you disconnect the fuel line, oil lines and pull the carbs out, drain the fuel from them and set them aside for now. Remove the existing reeds and the gaskets from the block and clean any debris from the block, as you'll need new gaskets to seal the new reeds. While the stock reeds are out, it's a good time to check and see if the pistons are in good shape. They should have a dark gray coating on the skirts with silver tops and all should show no nicks or scratches. If there are any major marks on the piston skirts, crowns or rings, you should be considering new pistons and rings, as the old ones won't be sealing against the cylinder walls and you'll be down on horsepower.

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Installation of the Good Stuff
Now you’ll want to install new gaskets, reed spacers and reeds into the block. You'll need to get longer bolts to install these reeds, as the spacers will be pushing the reeds out a quarter of an inch or so. Fasten with new 5x35mm bolts with a small amount of blue Locktite on them. Turning our attention back to the carbs, you'll want to take the float bowls off the carbs, clean the carbs and install new pilot jets. The 600 HO has been known to be hard to start because it's so lean on the slow-speed circuit, and installing reeds will make this worse. So you'll want to install size 20 pilots into the carbs and turn the fuel screws all the way in and then back them out one full revolution to set the proper idle mixture.

The small hole in the middle that looks like slot screw is the pilot jet. Remove with a small screw driver.

Assemble the float bowls again and be sure that the gasket that seals the float bowls to the throttle bodies is in the proper spot. Also check that the area where the carbs go into the reeds is clean. If they have oxidization on them they need to be cleaned so no air can leak past them. If air leaks in through here it could easily cause a lean condition and melt a hole in the top of a piston.

Notice the area where the carb contacts the reed boot no longer has oxidation on it. Apply a small amount of 2 stroke oil to this area before installing the carb will help stop them from coroding next time.

Next you need to hook up the gas line, choke and throttle cables, oil cables and carb heater. Install carbs into the reeds and tighten the clamps that hold them there. Install the air box, secondary clutch and toolbox. Give it dozen pulls and it will jump to life with more snort than ever … and now your dreams can turn to clutching this buggy.

The clean carbs are now ready to accept the upgraded reeds.

Shiny side up,
SnowMan

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