ok gang...i am a long proud cat rider...but i am getting a new sled and the yammi 4-strokes are looking pretty nice...i need to know the good the bad and the ugly of them...i am a large guy 6'3 300lbs dressed out...ride pretty much groomed and bummpy trails would do more off trail riding if it did not kill me and ride as aggressive as my sled can handle...i would like some of you experienced yammi-4 strokers advice...models, displacement, etc what ever you got for advice...thanks

Attack?

I'm still a 2 stroke’r, but I’ve ridden a few 4's.

Power depends on you really and what you are currently riding. If you are riding a 600 and that's as much as you think you ever need then look at an RS Vector. I had a fair amount of seat time on the RS Vector and it's not a bad machine. At 300lbs you are going to want to upgrade the rear to the FAT BOY spring (no offense). You'll probably also want to upgrade to the stiffer sway bar. Stock seemed fine to me, but I'm 170 without gear. They guys that actually own the RS Vector is about a perfect match to you height and weight wise. He has done both the mods I mentioned, hence I know about them, lol.

But if you're riding anything bigger 700+, then you're only going to be happy with an Apex (121")or an Attack (136"). I've never driven an Attack, but I drove an Apex RTX (rough trail sled) this weekend in 2" of fresh powder and I was amazed at how well it was balanced for off trail riding; was actually easier to carve powder with then my 03 Viper. I think the Viper would benefit from a bar riser for off trial riding (but it digress). Anyway, was very impressed with the machine as a whole. The guys that owns this one is also a very close match to you and also came off a Cat F7ext. Both these models are fuel injected, so no screwing with jetting! When I buy 4 stroke it will be one of these two.

The 05 RX-1 isn’t a bad ride either with the mono shock, but again I believe they were a little soft in the back end for heavier people. Easy filter mod makes these machines a real monster on the lake; neck and neck with my piped Viper.

Issues with some 4 strokes. Some are having problems with the oil tanks cracking at the lower mount point. It’s a rigid mount and the vibration causes it to crack over time. Simply insulating the tank from the bracket with rubber grommets seems to eliminate the problem. Other that have had the chain case apart are experiencing leaking after re-assembly. I think some forma-gasket would help seal thing up a little better. There is also a newer chain case cover that fixes the issue.

Hope that helps.

I'd think the 09 Nytro XTX is in order for your style of riding...aggressive, plus the longer 144" track should be great off trail.

I live in AK and do a lot of riding like you on long bumpy trails as well as some deep powder off trail riding.

I am 240 in the raw but then add the 15 lb backpack, 5 lb cold weather gear 6 lb rifle, and I am not far from your weight. I own a 07 Attak (A $10,000 sled that you can pick up for $7,500 new out of the box) and I really think it is the sled for my build. Can still lift the front skis off the ground, get a lot of air on jumps, and out of the hole and can get from 0 to 60 in 4 sec's (according to sleds od).

I added a set of Woody's studs as on ice tends to fishtail.
A pair of Powder Hounds with 6 inch carbide. (For deeper snow flotation)
Also a marginal snow wheel kit, a product called Water Wetter into coolant system, and ice scratchers as between trails here is about 5 miles of frozen rivers, lakes, and areas of little or no snow.

Hope this helps.

I'm your size, and off a long line of Polaris performance sleds. I haven't had anything smaller than an 800 for over 10 years. Sounds like we might have similar riding habits, and I think I know where you're coming from when you say you're a Cat man.

It took me about 5 minutes to fall in love with the Apex/Attak motor/chassis/drive train. A little longer to learn how to ride it as it was my first rider forward sled, but that's another story. 3200 miles on an '07 Apex RTX this season. The power on tap is completely addictive to the performance oriented, and I never get tired of hearing it. The power is there right now to lift the front over a mogul, or carry it off the top of a bump. There is NO waiting for a backshift to happen, the pipe to warm up, or for the power to come up onto the pipe. It's now.... The engine braking that seemed just nuts at first is now a weapon, a feature to be used a hundred different ways. The only caution to be made is a reminder of what's going to happen when you back off the gas to the riding buddy in back of you. Nor more tailgaiting. Time he figures out you've backed out of the gas, he's going to think you're a hood ornament if he's not carefull. This chassis is comfortable sitting Rev style, stretched out, or standing. No difference. I use all 3 positions regularly. I LOVE having that many choices, especially on longer trips. The Nytro seemed too aggresive for me - you ride too far forward.

I demand a bunch from my suspension, and as much as I tried to figure out a way to deal with the Proactive Ck, I never did. I was unhappy with it on so many different levels, I replaced it with a Poo suspension with dual clickers. This completed the perfect machine for me. The Mono suspension is likely much better - but be prepared to pay to have it tuned to your size and riding style. Reports from guys that have had that done at a couple of popular places are outstanding. The machine is picky if you're demanding - but capable if you are patient getting it dialed in to what you are expecting from it. Just me.