I have an '03 Kodiak 450 with about 3500KM (2500 miles). When I first got it, top speed was about 90KMH (55MPH). Now top speed is around 70-75KMH (40-45MPH). I noticed my air cleaner is a little dirty but nothing too filthy. I'll still clean it.

ALSO noticed my REAR beltcase tube was completely off. (this wouldn't affect power/top speed would it?). the front one has done this before, but never noticed the rear. there was no water in there as were riding dunes. I removed the beltcase cover (great thinking on the rubber gasket yamaha!! Honda wouldn't do that!). Anyways, inside of cover is a little dirty, nothing too serious. the front, outer sheave is packed FULL of black, thick grease. I assume this is normal? belt isn't cracked or anything.

Sooooo, how do I know when belt needs replacing? Is there any adjustment? do the sheaves/clutches need servicing (if so, what type and how)? I have cover off now, so anything I need to do, I'd like to do now. ALSO, I've heard a clutch kit consisting of a heavier spring will wake these up. anyone done that? where do you get best prices on kit? or belt? ( I heard Dayco makes belt for this quad).

Any other clues or thoughts on my top speed loss? sorry for the long post, wanted to provide as much info as possible to assist those in the know. AND THANKS FOR ANY HELP!!

I have an 03 kodiak also and when I first got it I was running around the 55-58mph. After a month or so went buy it droped to about 47-49. I took it to yamaha and they looked at it and looked at it and said that it was fixed. They told me that there was dirt in the gas tank and carb and they tor it apart and cleaned it all up. I pick it up drive and hour to get home and went out for a drive and still top speed 47-49. Took it back to them the same day hotter than hell. I mean I am pissed off bad!!!! They put a new belt in it and called me the next day and told me that it was done and that the belt needed replaced and that they was so sorry that they didn't catch it last time. I get there to the dealer and they said they was so sorry and they gave me a chain saw bracket for the head ache and said sorry again. I thought that it has to be right now their is no way that it isn't after all this. I get it home and still 47-49, I then call them pissed again and they asure me that there isn't anything wrong with the bike that the speedo had to be wrong before or something. Make a long story short it still to this day only gets to 47-49 mph. It will hit 50 down hills lol. As far as the beltcase tubs I notices that everytime I went threw water my belt was getting wet. Both of mine was lose abd about 3 or 4 other people that I talk to said that thiers was lose also.

Try keeping your tire pressure up, maybe 15#. I'll bet its faster

thanks for the replies. I've heard other guys post some interesting fixes for those loose vent hoses. one guy used a tin can as an insert/sleeve, so the clamp had more than plastic to squeeze to when tightened. I run my tires at 3-4lbs for the kind of riding we do. that's also what they were at when i had a better top speed.

still wondering if I need to do any other maintenance to the clutches, OR, consider clutch kit, while I have it all apart.

I know on the KFX700s clutch spring really help with power. Look into getting one of them. I think they are less then 30 bux or so.

Hope it helps.
Kevin

so far I've found a clutch kit by Dalton, and one by EPI. Both around $170 + shipping. $30 sounds a lot better! is that just a spring , instead of a "kit"? the kit looks like it has rollers, springs and some bearings.

a friend said the clutch kits are a waste of $$. they AREN'T cheap. anyone else? I just want my stock performance back.

ALSO, what is the wear limit on the belt? ( I assume it's a minimum width??).

I've has the same problem with my 05 Kodiak. At first 50 MPH came easy but now 48 tops. I just had the belt checked and the belt compartment cleaned while having an EPI clutch kit installed. The clutch kit helped considerably at low end but did nothing for top end. The cleaning didn't seem to help either. Seeing as how I'm stuck with this ATV awhile I think I'll try the HMF slip on exhaust next. And to be perfectly honest, only rarely do I need to even go faster than 40 but it's nice to be able to.
Buck

ya, we RARELY hit 40-50MPH, cuz we're on trails or logging roads, and it's just crazy to try.BUT, like you, I wanna know my power is still there. Did you get the mud-riding upgrade clutch? I noticed on ebay, there are about 3-4 different types of clutch upgrades... for high altitude, mud riding, regular, etc...

This past weekend I got up to 55-57mph a couple times on backroads...On totally flat ground (backroads)I hit 55 all the time. Gotta keep up with the pack.