mopar1rules Posted June 12, 2012 Report Share Posted June 12, 2012 Maybe we can go about this a bit more scientifically. A couple thoughts here: one, this isn't about blame; I very much doubt the reputable builders here would knowingly sell inferior hardware. I realize they're also in an awkward position on this - if they give us the results of any serious technical analysis of the cranks or crank parts on the market, whether theirs or another company's, they're also handing that info to their competitors. On the other hand, "trust me" is sort of a tough pill to swallow when we're talking about exceedingly expensive motors. It's a given that correct installation and tuning is essential to crank longevity, but it's also a bit silly to pretend that the quality of a crank is an insignificant factor. All this "any crank can fail" stuff fully misses the point, i think, that some cranks will fail more than others. There's nothing unreasonable about trying to work out, as a community, which cranks those are. So, to the point, two proposals: one, that we set up a form similar to the jetting questionnaire to log crank failures, incl type and location of failure, type of rods and bearings, other motor mods, known contributing issues (air leaks, improper squish, etc), riding style and approximate ride time. This is essentially what dealerships do to know if a part has an unusually high rate of failure. Second thought is we could take a collection for independent metallurgical analysis of available cranks on the market, which could be posted here for the benefit of all. I have no idea what this costs but would be happy to look into it. Any engineers here want to pipe up? 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. 1 Quote Link to comment Share on other sites More sharing options...
locogato11283 Posted June 13, 2012 Report Share Posted June 13, 2012 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. Why is it silly? Some of these motors are 100+ HP and are hot lapped in the sand for hours on end. OF COURSE they are time bombs. Do you really think that these motors should last for years with basic maintenance with the beating we put on them? I sure don't. ANY WELL built engine, regardless if its 40hp or 80hp, will be just as relialbe as stock. Not true at all. You're doubling or tripling the power of these motors and that in itself makes them less reliable. You can use all the best parts to help with the added stresses from extra HP, but in the end you're still pushing the motor to the limit. 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. More inaccurate statements. I agree that jetting and oil play a big part in the life of the motor, but there are a ton more variables out there that can and will cause a motor failure. I have said this time after time and not just about this crank thing. These are HIGH PERFORMANCE motors that are pushed to their limits every time we take them out. I seriously doubt that everyone is tuning them every time they take them out. Variables change every time we ride thus causing the motors to perform and act differently. To expect builders to assume full responsibility for these motors is absurd. The owners must take some of that burden or there would be no room in the ATV world for high performance Banshee parts. Quote Link to comment Share on other sites More sharing options...
mopar1rules Posted June 13, 2012 Report Share Posted June 13, 2012 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. Quote Link to comment Share on other sites More sharing options...
mopar1rules Posted June 13, 2012 Report Share Posted June 13, 2012 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. Quote Link to comment Share on other sites More sharing options...
stroking Posted June 13, 2012 Author Report Share Posted June 13, 2012 i wonder whos making the rods in those blown funny car,nitro,turbo 1000-2000hp motors a 110hp motor should NOT be so unreliable when street bikes make alot more as well as stated above snowmo Quote Link to comment Share on other sites More sharing options...
mopar1rules Posted June 13, 2012 Report Share Posted June 13, 2012 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. Quote Link to comment Share on other sites More sharing options...
shanYE west Posted June 13, 2012 Report Share Posted June 13, 2012 keep in mind that the sleds operate off a cvt. This keeps the motor running at a very narrow RPM range thus not allowing for over rev or heavy loads put on the crank. Last I checked.. I dont remember seeing race cars make it 200k miles. Wonder why NASCAR's rebuild their motors after every race.. Any time you modify the motor.. it decreases its life. If you want the most reliable banshee.. keep it stock. 80hp is almost triple the power the motor was intended for. Its going to fail.. its just a matter of when. When you modify the motor.. your increasing the probability for a failure.. thats just a fact. Quote Link to comment Share on other sites More sharing options...
mike0chek Posted June 13, 2012 Report Share Posted June 13, 2012 Isn't the rz350 rated around 60hp? and doesn't it use the same crank as a banshee? i think you are correct sir Quote Link to comment Share on other sites More sharing options...
shanYE west Posted June 13, 2012 Report Share Posted June 13, 2012 Isn't the rz350 rated around 60hp? and doesn't it use the same crank as a banshee? 60hp is either at the crank or one wheel (motorcycle).. RZ350's use a different trans ratio also.. Streetbikes tend to operate at a lower RPM range then off road applications. gotta compare apples to apples here... Quote Link to comment Share on other sites More sharing options...
shanYE west Posted June 13, 2012 Report Share Posted June 13, 2012 that depends a lot of the rider. Nick, You can't even compare.. Street bikes operate at a maintained engine RPM typically MUCH lower then peak RPM.. ATV's opperate at near peak RPM their entire life. also.. you said rider.. So the engine reliability is up to the RIDER! Quote Link to comment Share on other sites More sharing options...
tedd1 Posted June 13, 2012 Report Share Posted June 13, 2012 Wind 'em up to 10k and dump the clutch (some on pavement)...Ya, that'll last a looong time... Quote Link to comment Share on other sites More sharing options...
mopar1rules Posted June 13, 2012 Report Share Posted June 13, 2012 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. Quote Link to comment Share on other sites More sharing options...
mopar1rules Posted June 13, 2012 Report Share Posted June 13, 2012 And nascar rebuilds engines to have the most perfect engine everytime. Not because it doesn't run. Quote Link to comment Share on other sites More sharing options...
shanYE west Posted June 13, 2012 Report Share Posted June 13, 2012 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. the clutch adjusts.. and then the belt will slip momentarily. a CVT trans is easier on cranks.. end of story Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted June 13, 2012 Report Share Posted June 13, 2012 60hp is either at the crank or one wheel (motorcycle).. RZ350's use a different trans ratio also.. Streetbikes tend to operate at a lower RPM range then off road applications. gotta compare apples to apples here... Wait what? My bike revs out to about 16500. I shift at 10k I think that's a lot more then my banshee will see. Quote Link to comment Share on other sites More sharing options...
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