When will they wake up? 2014 hopefully

[Grimm]

A one piece hood would be great again.

 

[T-Bone]

In the lead up to the 2014 Corvette reveal last night, engineers made the statement that they wanted light and that "every gram had to earn its way onto the car." I hope Yamaha takes the same approach and doesn't use the excuse that it was too expensive or that durability suffered too much. I'm sure it is a challenge, but if the "new" sled is not significantly lighter, then how has it evolved?

 

[couch]

I recall the Nytro motor was a few pounds lighter than the Vector motor it was based on. Four stroke engines are heavy, no doubt about it when compared to a 2-stroke but I bet the the Yamaha 3-cylinder is lighter than the Suzuki 1100 twin. It would be interesting to see how it compares weight wise to the Rotax 1200.

Yamaha has a good thing going with how and where they mount their engines. The extra weight comes from the heavy stock battery, reverse gear, stock exhaust, steering system, skid-frames, big steel plates in the tunnel, the radiator, steel handlebars, and finally way too many body panels and covers.

The mountain sled forums on this site are a great place to see how much weight can be removed from a Yamaha. The problem is it quickly becomes very expensive and it seems that a lot of the Yamaha's become front heavy even with weight loss plans using a stock chassis. It is way easier and cheaper to remove weight off the back of the sled than it is the front.

I remember feeling the difference on my Vector when I installed a Boss seat and White Knuckle exhaust. The back end was lighter and the sled no longer felt as well balanced.

The aftermarket lightweight parts cost $$$$ (engineering, materials, manufacturing). No doubt Yam could provide some of the same weight savings at a better price based on scale. As for the balance issue (Nytro) seems that the +4" or more aftermarket front ends have remedied much of that issue ... on my 07 Nytro the spindle is 3" or so closer to the clutch then it is on the 07 phazer and the phazer seems to be have better balance. From reports Yam race front end clip offers similar advantages. If the balance is centralized then the extra pounds for the 4 stroke would not be so noticeable. The Timbersled suspension in my Phazer Mtn is a big weight drop from stock! Reverse is mechanical on 4 stroke which will add weight for the same feature compared to 2 stroke ... not sure if there is any way around it but I wouldn't want to give it up!

 

[09nytro]

Who fell asleep and how long have they been sleeping ...

 

[V-maximum]

Not for the groomed trails
This tread is about how bad Yamaha sleds handle off trail
We ride everywhere in 4-10 ft of powder
The reason why you see the doo guys riding off into the trees jumping around is because they handle 10 times better than a Yamaha and they are way more fun and effortless to ride. I'm not here bashing Yamaha but when I ride I want to have fun and its no fun tipping over and being stuck needingthre guys to pull your skis and push to get it out and do it again in 20 mins. Who ever says Yamaha shouldent make two strokes don't want them to be first in sales. Not cause the 2 stroke is better but there's a huge market for 2 stroke snowmobiles that they don't even get into. Ill say it one more time I know my sh!t about sleds and engines. If you want to have a 450 lbs 4 stroke and 160 hp they need to bore out that phaZer engine to1050 cc and see where that takes them I would guess around 120 hp. Nowofcourse the crank would be bigger valves and other parts but the engine would only be and extra 25-30 lbs max. So it will probably be about 100 lbs. turbo that from factory and a new apex or v- max is born lightweight n powerful. Get rid of 3 & 4 cylinders under the hood.they are too heavy. They can do it. I know these engines are awesome but they are killing Yamaha more than anything else on the weight issue it's also causing them to build a heavyweight chassis to hold it so in conclusion if the nitro engine is 200 pounds because it is at least 165 lbs u loose 65 lbs just in the engine I'm sure with a lighter engine u wouldn't need such a overbuild frame to hold it. So all of a sudden u got almost 100 pounds off the sled with new engine n chassis and that's not counting exhaust and a ton of other stuff. So if ghetto can shave 30-40 lbs off suspension and other overbuilt parts you got this sled with 120-160 hp(160 with factory turbo) and it weighs probably
About 485 lbs which I think would be a winner.
Now as for the Yamaha direct injected two stroke. Please don't say I would never go back because of reliability because I see old Tammy's with 20000 km and never had the engine rebuilt. Magine what they could build now. They don't stink as bad and there great on fuel. So whoever dident thing those doo guys army having fun carving things up and jumping should drive one. Then you be like me wondering why why why did they drop 2 strokes all together. Mabie they all thought they never make emissions but guess what there just as clean as any four stroke and ill tell u this the most complete burning engine in the world is a two stroke diesel in huge tanker ships. So I think there's alot more to two stroke tech and that it is the fucture in the snowmobile industry. But I'm not here saying drop the four stroke but drop a few cylinders Yamaha. Make the power with less cylinders and start building two strokes again and I bet your sales will double in the first year with hughe demand for a Yamaha direct injected two stroke. Like it or not guys I'm 100% correct. So support this thread and make more like it if you want them to listen. They can make them alot better

 

[brad d]

I had a rc51 Honda sport bike. It was a twin 999cc made 128hp and 70ftlbs... That would be cool. 10,000rpm. Is that too much for a clutch.

 

[Sled Dog]

Yes it is 9000 is the magic number for the belt.

 

[AKrider]

I don't very many people who are members on this site will ever be interested in going back to a 2-stroke. I think by and large that most guys on here went with a 4-stroke Yamaha with engine reliability being their #1 concern.

I totally agree with you that the 2-strokes work better off trail and in the mountains. They also have a lot more engine failures. One of the reasons the Yamaha 4-stroke motors are heavy is because they are based off street bike designs and technology. They could lighten the motors up by using 4-stroke MX bike design and technology. I don't know if thats a good idea or not. I read lots of things in forums and on the net about the new 4-stroke MX bikes not being reliable. They aren't like the old Honda XR's that ran forever. Even the Phazer motor (which is two cylinders off an RX-1 motor) is not as reliable as the 3 and 4 cylinder models. IMO, Yamaha needs to take weight off the chassis to become more competitive.

The XC race Nytro's are much improved over the consumer versions and the race front end does extend the wheel base out further forward which in turn puts the motor more towards the center of the chassis. The 128 track further increases the wheelbase. I think Yamaha could use the same principles in a new chassis to help center the weight. I think they should also look at putting the gas tank under the seat like the other 3 OEM's. Last night I rode my RMK around with 1.5 gallons left in the tank, filled up with another 10 gallons and did powder turns on my way home and the additional 60lbs in gas was not very noticeable. On my Nytro with the Trail Tank I could immediately feel the weight of a full tank. I think having the gas carried low makes a big difference in improving the handling.

 

[yamaha1973]

Even the Phazer motor (which is two cylinders off an RX-1 motor) is not as reliable as the 3 and 4 cylinder models.

Actually its more like 2 YZF 250 motors, dont know about compromised reliability but it sure is a fun power plant!

 

[Supa Dexta]

Newer 4stroke mx bikes are a pita! My kx is a bitch to start if the gas sits in it for more than a few weeks, you'll kick the foot right off your leg before it goes. They are very high strung, and aren't nearly as long lasting the old xr's and whatnot were. Def fun and powerful, but not suited towards a sled.

 

[Schlorven]

wankel engine, http://bargerltd.com/products.htm

 

[low slung]

My brother purchased a 2012 YFZ450 carb last may.This motor like many 450 dirtbike based four-strokes are pretty high strung(short stroke,high RPM).The reason they don,t last like regular thumpers is the conditions they are operated in(dust,dirt,sand).One of the best ATV engine builders in the business(CT knowles)said what kills these high strung 450s/250s thumpers is dirt in the intake(dirty air filter).Thats why you have to clean the air filter alot more,run filter skins,and change the oil/filter ever 10-20 hours.The phazers engine,while high strung lives in a relatively clean conditions(snowdust=water vapour).Thats why the phazers motor is such a marvel of engineering(and still more reliabe than any new two-stroke).

 

[AKrider]

Actually its more like 2 YZF 250 motors, dont know about compromised reliability but it sure is a fun power plant!

From a marketing perspective only. This motor was discussed at length back when the Phazer first came out and it shares its design from the RX-1 engine. But, from a marketing point of view, how many Phazers are you going to sell saying it uses half of a RX-1 ton motor?

That brings me back around to MX bike technology. The service intervals for a modern 4-stroke MX bike are very 2-stroke like. You should be replacing not only the piston/rings every X number of hours but also the valves and cam chain. Some engines are worse than others (believe it or not Honda). One article I read by Eric Gorr said the Honda head was disposible!

 

[couch]

ill tell u this the most complete burning engine in the world is a two stroke diesel in huge tanker ships.

Strange comparison. 2 stroke diesel engines still use same type lubrication system as a 4 stroke (oil from base through cooler and back to base sump) and on old style they just use ports on side of the cylinder for intake / exhaust so yes simpler but nowhere near as efficient ... add valves, cams and associated parts to get better efficiency (still 2 stroke) and you are almost back to 4 stroke complexity. Of course scale is different and you are comparing diesel to gas.
Have had 2 stroke marine diesel engines and to be honest they could not hold a candle to the electronically controlled 4 strokes that we operate today! Cleaner, more hp, better economy albeit they are more expensive and cost more to maintain.

Phazer @ 500 cc delivers 80 to 85 hp @ sea level .... its a fun little engine. Turbo / super they have been ramped up to 130 to 140 hp but that's a lot to expect from 500 cc and from reports they have a short shelf life when the boost is turned up without beefing up internals.
Power is not the issue, Yam has it in scads and its available much earlier on in the 4 stroke. Weight on some of the components can be reduced ... seems like everyone is in agreement on that issue.

 

[Sled Dog]

ill tell u this the most complete burning engine in the world is a two stroke diesel in huge tanker ships.

Strange comparison. 2 stroke diesel engines still use same type lubrication system as a 4 stroke (oil from base through cooler and back to base sump) and on old style they just use ports on side of the cylinder for intake / exhaust so yes simpler but nowhere near as efficient ... add valves, cams and associated parts to get better efficiency (still 2 stroke) and you are almost back to 4 stroke complexity. Of course scale is different and you are comparing diesel to gas.
Have had 2 stroke marine diesel engines and to be honest they could not hold a candle to the electronically controlled 4 strokes that we operate today! Cleaner, more hp, better economy albeit they are more expensive and cost more to maintain.

Phazer @ 500 cc delivers 80 to 85 hp @ sea level .... its a fun little engine. Turbo / super they have been ramped up to 130 to 140 hp but that's a lot to expect from 500 cc and from reports they have a short shelf life when the boost is turned up without beefing up internals.
Power is not the issue, Yam has it in scads and its available much earlier on in the 4 stroke. Weight on some of the components can be reduced ... seems like everyone is in agreement on that issue.

Very true we used detroil 671 two stoke diesels engines on the smaller oil rigs and yes they have their own oil system that has to be changed just like a 4 stroke and very dirty slobering engines to boot.