I hate giving clutching advise. Only you know the personality of your machine. If you want to keep it real simple though my advice to you would be to drop one tooth on the top gear for starters. Top gear has 22 teeth. Drop to a 21 tooth top gear. It uses the same chain so no worries and it's a cheap upgrade. I paid about $25 for a 21t top gear at my Doo dealer. For the record I actually gained a few mph in the top end by gearing down. I was now able to use more of the clutch ratio and got higher track speed because of it.
Inside your primary you have a spring, weighted pins in the tra arms, and of course ramps. Leave the ramps alone but get yourself a set of adjustable pins from Dalton. Remember that flyweight determines rpms. Need more rpm then remove weight...need less then add weight. Dalton manufactures several different kits for the pins. The stainless ones are great and the kit I have does go up to 25 grams. Which is alot.
I would also change the primary spring. My 04 REV 600 H.O. had a 160/290 primary spring. I then jumped the start force of the spring up to 200 but left the finish force the same. So I used a 200/290 spring. This bumped the engagment up a few hundred rpms and I found I was also over revving just a little. I added a little bit more weight in the pins and then it was perfect.
With this set up a 54/44 helix works well. I'm not sure what your 05 has in it for a stock helix but on my 04 it used a 47/44. The 54/44 worked very well.
This was a decent set up for me and my sled. However there was lots left on the table. I tried different set upos and even went to a Hyper Lite roller secondary that was amazing but a little finicky and suddenly developed a bad habit of cracking. I now am running a clutch kit from Dynamo Joe over at Northern Catalyst. It's a great kit that needs very little tuning and the change in attitude from a stock sled to what I have now is like night and day. It's not the worlds best drag set up. But it's one of the best trail set ups that gives great acceleration and backshift all in one package.
All of this is uselss though if you don't tune the suspension to use the set up. I'm running a 1 5/8 Sno X track and have played around with the suspension enough that it just plain hooks and hang on because it's giddy up time.
Here's Joey's website:
Click right here to increase your clutching IQ[/b]