The old Honda 420 was a bit of a disaster. Being light weight and high powered, it wasn't good on slippery terrain, so didn't pull the sheep trailer too well. Also the rear axle gave trouble from day one, within twelve months of launch, pattern part makers were listing replacement axle shafts, we have had many axles fail, and three out of four 420s will have a loose axle spline when they come in for service. Honda could have got round the problem by selling a manual version of the IRS 420, but they didn't.

Unless I got a "bad un" to service, the Yam 450 has a gearbox problem. Yamaha chose the wrong weights or spring for the variator, when riding, you are continually wanting it to change up. If you get the chance, ride one and then ride a 450 King Quad, which does have a good CVT.

 

Problem with the 450 KQ is it was a full size 4x4 , it had the same chassis as the 750KQ.
2010 Suzuki KingQuad® 450AXi ATVs A 672lb 450 ATV.
My friend has a 2007 450 Grizzly , he had no problems yet. I call it a shrunk down 660 Grizzly.
Unlike the early 420 Honda it always had IRS and diff lock.

 

I remember the 420 rear axle problems. Never heard about any problems with the Yamaha 450 though. I still question Yamaha's decision to mothball every 4x4 model except the 708cc Kodiak and Grizzly. Kawasaki only has the little Brute Force 300 and the Brute Force 750. Both of them are missing out on the 500cc class that is the best seller of all of them. Yamaha at least had machines in this class, Kawasaki never really did though. Kawasaki either had a v-twin 650 or 750 that had solid power but was pretty expensive new and then you drop down to a 400cc or 360cc 4x4 that was cheaper but underpowered and slow. A machine somewhere in the middle would have been a good seller but they never built it.

 

"Problem with the 450 KQ is it was a full size 4x4 , it had the same chassis as the 750KQ."

My point is the CVT works well, despite the weight, the one on the 450 Yam doesn't, nor does the 400KQ CVT for that matter. Nothing puts you off a bike faster than an Auto box that doesn't change right. We tried selling TGB 425 Blades and found the same problem put customers off, luckily as it happened, because the demonstrator was passed on to the boss's son, and continually broke down, so we gave up on TGBs.

 

I had a Wolverine 450 before and I didn't notice any problems with the cvt. I guess its a little different than the Kodiak as the Wolverine didn't have low range. I think it was simply geared a bit lower to compensate which knocked off some speed on top end. I think its a good compact 4x4 quad for trail riding. Not much utility in it though, didn't even have racks stock but a small rear rack was available as an aftermarket accessory.

 

Yes, you can forgive a bike with no low range being a bit low geared, the Bruin was, but it seems that Yam used a similar CVT/Axle ratio for the 450 Grizzly when in high range, the low range is a real "crawler" set up.

 

If a CVT is working right you should feel no shift , it's just gas and go and should linear from stop to top speed. All my atvs did even my sleds.

 

I think Merryman is saying that the cvt setting for the 450 allow the engine to rev too high to keep moving. Its not really that it doesn't work, its just not as efficient as it should be. Loud and annoying and probably hard on fuel. Probably more cvt whine than there should be. I've just accepted that every cvt quad is going to have cvt whine, thats the reality of the system. If you were sitting that close to the engine and transmission in your car or truck with no cab and glass to shield you from the noise, think about how loud driving it would be.