mopar1rules

That's correct guys.....the reason that rod broke is because you guys didnt have a "pro" engine builder like M&M or some of the other "pro" builders that are members of this site. You guys forgot that these "pro" builders shit differently than us and put on the pants differently than us, and that makes all the world of difference in engine assembly. Pffffft......THESE RODS AND CRANKS ARE WHATS FUCKEN JUNK!!! ITS NOT IN THE ASSEMBLY OR JETTING OF THESE ENGINES THAT CAUSES THE RODS TO BREAK. ITS CAUSE THAT WANG CRANK GUY DOEAN'T HAVE THE SLIGHTEST CLUE ON WHAT IS A PROPER MATERIAL TO USE TO MAKE A ROD. YOU NEED SOMETHING WITH SOME FUCKEN YIELD STRENGTH!!!! For all of you guys out there that have this 29L/R crank in your atv, tear that bitch down and throw the crank away, before it makes you HAVE to throw the whole engine away. Its not worth it. Sure you can listen to the guy that sold the crank to you, telling you to keep it in there, cause when it breaks he will sell you more parts to fix it and he wins twice on you.

Any porting done to the 380 bb cylinders?

www.hooperraceengines.com/Raceengines.html

Specialblend07, don't pay to dry and get the dumbass n2otoofast4u to try and understand that sleds make serious hp. He's aparently a 16 yr punk with a fast boost bottled banshee.

n2otoofast4u........you are a dumbass! You have no clue wtf your talking about. Late 70's vintage Yamaha 440srx and ssr sleds did indeed make those kind of hp numbers. And where the fuck you look or who did you talk to, that said a 1000cc thundercat sled fully modded barely made 100hp? That source you got your info from should be punched in the mouth. A fully race mod 1000cc cat will make over 200hp!! No problen with race pipes, race porting, big carbs, race gas comp, and hotter timing. And wtf you mean the 1000cc thundercat is a counterbalance motor. No its not!!

most of the time the port timings get a little to jacked up when running a spacer plate. if i remember right, the blow down time drops to like 26-28 deg. too low IMO for a banshee with good pipes.

this is very true too

Yeah and i bet 90% of the big bad ass banshees out there have snapped and blown some of the hot rods rods too.

Hell you can take a price 1000 big bore for a srx and make 245 hp with it.

For the idiots on here who don't believe the posted hp specs of sled engines, you better start google searching. Sled engines fucken rip. Hell, even the yamaha ssr440 and srx440 sleds in the day, made any where from 85-105 hp. And they were only 440's!! My uncles ssr would run 105 mph in 600 ft! Lets see a taiwan rodded banshee do that!!

Fyi......2 yrs ago a semi-local individual ran a vmax 4 with a turbo, making record hp set on dynotechs dyno. It was like 563 hp. He has bone stock bo ttom end!! He blew the track on it at like 150 mph!! Motor still kicking and its running on 42 psi of boost!! Stock rods are strong! The oem banshee cranks on ebay probably have bad rod bearings. That's from lack of oil, poor oil, lean jetting, debris ran thru engine, etc. I would sure hope a 800 mxz crank has larger rods and webs over a banshee crank.....its over double the cc size!! Also yamaha does have 115mm rods. Exciters, phazers, and I think SS440's used them. I was told rd400 has 115mm rods.

Yamaha has also been know to build some of the most conservative engines. They leave much on the table and also slap 20:1 oil-gas ratio stickers on our gas tanks. That's over kill! A buddy of mine races dirtbikes. He has a yz250 and broke 1 rod......it was on a wiseco crank. Never broke a OEM rod. He doesn't baby the engine and his 4th place finish at Loretta Lynns proves it. And that bike probably makes like 55-60hp. But then again.....high quality Japan rod.

Exactly! The current high failure rate of the taiwanese rods and recent engine failures is from the piss poor rods. I don't think any of the people that assembled their engines, did anything different this time around, versus with the OEM crank. Everyone has the right to believe what they wanna. I will continue to believe my OEM crank is FAR stronger than any aftermarket crank and that higher hp motors can be as reliable as a stock motor. I know of a guy that has a 195 hp sled motor that was 145hp stock, that's in his trail sled for 10 seasons. No issues with the stock crank. Also, not every sled engine comes from the factory rich. All of the ski-doo sleds since 2003 are too lean from factory and that assited in many piston seizures.

How come a hot rods rod will break on a 65hp trail motor and a stock OEM rod will hold up?......better quality in the OEM rod.

The reason for a race engine to fail is because one of the parts or more, weren't heavy duty enough to handle the hp and stress and load. An example.....a small light duty low rpm rated bearing installed in an application where high rpm and high load duty bearing is needed. Sure the small bearing will last, but only for about 5 min or whatever, where as the correct bearing will last way longer. Same thing with 29L/R rod.....it will take the 60-80hp for about 1 tank of gas and then quite, where a japanese rod will take it for much longer. If its built well enough, it will last. Top fuel cars also run aluminum engine parts for lightweight. An aluminum rod won't last as long as a forged steel rod.

And nascar rebuilds engines to have the most perfect engine everytime. Not because it doesn't run.

Sure sleds have cvt trans, but they still see high loads at times. How about trail riding and spinning in the soft snow and then you catch a patch of frozen ground and the studs bite and the rpms drop some and then recover. Can't tell me that wasn't a load. Far more of a load than what my banshee sees when it just spins its wheels in dirt, on grass, snow, etc. Sleds see just as high of a load as a atv engine and probably spend more time at max rpms. On a atv you get rpms up, then let off, then shift, then bring rpms up again, etc etc. Sleds you pin it and it stays whinning out at 8000-9300, depending on the engine and you can hold it there for miles down the trail and no rods snapping. And the pistons are heavier from having larger pistons and still good to go. Bottom line is aftermarket Taiwan banshee rods suck and are weak. End of story.

Exactly! Hell, Arctic Cats 1000cc thundercat sled makes 172 hp stock and doesn't blow rods. The reason these banshees are so called "time bombs", is because of inferior aftermarket parts. There is still no reason IMO that a 80hp banshee should be a time bomb. I guess the people that think that, have that mind set from their poorly built banshee, blowing up everytime they ride and now they think that's the common consenus......that banshees are suppose to be time bombs.

Also, yeah some are pushing their engines to their limits, but the guy making 60hp sure ain't. And how come sled engines can make 145 hp stock and not blow rods? Thats quite a bit more than these banshees make. Its because the Japanese rods are made out of a much better material choice for con rods. Something the aftermarket Taiwan con rods lack......quality material, hence the common breakages.

I agree that blaming the builders is upsurd, hence the reason it bothers me so, to always read "have a pro build it". Some to near alk the blame needs to put on the makers of the shitty rods. And just because we don't have a sign that hangs outside our workshop that says "M&M" or whatever, doesn't mean we aren't builders or know what we're doing. There are many "pro" shops out there that fuck shit up and don't do things the best way. Prime example is Trinity.

Some of the best stuff I seen posted in a while on here. I agree that I don't think the site sponsors are deliberately selling less than superior parts, but I do feel that "these engines are ticking time bombs", and "you should be expecting these engines to blow up sometime" and "every crank fails" and "you need a pro shop to assemble your motor", etc is a bit silly. ANY WELL built engine, regardless if its 40hp or 80hp, will be just as relialbe as stock. It all comes down to proper jetting, good oil and oil ratio, etc, but at the same time, the material the components are made out of need to be able to handle it, and the 29L/R shows otherwise. I understand that the sellers/stores of the cranks, can't tell how the customer assembles his engine, but c'mon.......these rod failures are most likely not from poor install. Even lean jetting isn't going to cause a rod to snap! Andy from M&M already stated that the Kingrod 29L/R rod has very little yield strength, which is the rods ability to stretch and return to original state. The first guy to post in that other thread of having a 29L/R rod break, causing his 421 cub motor to go south, is a perfect case where the low yield strength rod shows its weakness. What also compounds the problem of the low yield rod, is the heavier 68mm piston that is now swinging back and forth at 9000+ rpm, wanting to stretch the rod even more so than a near stock diameter/weight piston, so the big bore motors will most likely suffer a 29L/R rod failure first. Anyone follow me?? And how often has a stock OEM rod let go, even on our 70hp ported OEM cylinder motors?......Like never! Tells you that the Japanese rods are made out of the correct material......one that offers the proper yield strength.

True that!

Where did you find that LA Sleeve big bore kit? I didn't think they were made anymore??

What's the deal with unstamped CPI's? Did they have stamped versions that sucked or something?

IMO a rod that breaks at idle or bends upon the rider trying to kickstart the engine, is a junk rod. If it was a good rod and a durable peice, it would hold up fine. It sounds a little like the sellers want to mostly blame the rod failures on "poor assembly", or "not being a pro engine builder", or "deto". Bullshit to the "have a pro engine builder do it, cause you need to be more open minded with a custom build crap". If the rod is shit material, its gonna break, wether or not jeff at FAST installs it, or M&M installs it, or Herr jugs etc! I have a Vitos crank purchased now, that should be arriving tomorrow and I will let you all know how it holds up for me.