bansheesandrider Posted November 5, 2009 Report Share Posted November 5, 2009 ok, got a email back from them, seems to make sense.... The center half-circlip groove is there to locate the crank axially. It takes the place of the usual drive side retaining groove/circlip. We have to do this when running roller outer mains; because these are no good at coping with any side loads. They are designed to have double the radial load-carrying capacity of ball bearings though; so what we do is we have a hybrid crank with balls for the two center mains, one of which is used to locate the crank axially - and then rollers at the ignition and drive sides ... and hey presto, we have the strongest possible crank that can be built. And then we have an o-ring on the other center main. The two outer mains don't have circlip grooves or o-rings and they don't need them. This is because the crank is what is called a 'floating crank' whereby the outer two mains are a hand slide fit; the same as the main countershaft bearing. And so these bearings are not fixed to the crank the same as a conventional crank, and this prevents binding between the bearings, which otherwise would impose side loads on each other - thus robbing the engine of horsepower. All GP engines run floating cranks. It all sounds reasonable, maybe a hair nuerotic but they are really looking for every HP they can with the lightest rotating mass.... checkout their webpage at www.twostrokeshop.com Cheers I have checked out their site, I am thinking about their transmission bearing kit. What they are talking about applies to a 90 degree firing crank with the TZ style PTO bearing, not the traditional 180 degree firing Banshee crank that you would get from Wiseco or Hot Rods. So if you are running a TZ style bearing then maybe you should have a groove for the circlip but I would not groove for the O-rings. If you are going to run the TWo Stroke Shop crank, then send them your cases, let them machine them as they see fit and make them stand behind the motor. Quote Link to comment Share on other sites More sharing options...
lt1bird Posted November 5, 2009 Author Report Share Posted November 5, 2009 Thats a tough one. Im planning on going with thier kit. But would love the option to use the trinity kit. When using streigh cut gears most folks use a tz style bearing anyway... I guess thier bearing is massive thus the need for moving the clip inboard.... Seems to make sense. Im still email them on the proper maching of the case for the clip and the 485 case bore.... I think its only the bottom 1/2 of the case that gets the one 1/2 moon groove..... I could send them the cases but the turn around time might be an issue..... Quote Link to comment Share on other sites More sharing options...
AKheathen Posted November 6, 2009 Report Share Posted November 6, 2009 ah, i see.....you might have shared some of this info earlier.........now, are you talking about floating the inner race of the bearings on the crank? thereare much better options than that.... Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted November 6, 2009 Report Share Posted November 6, 2009 Yea I would not want a floating crank. I would emagine that would really eat up the cases. I run a 4mill crank with standard bearings with o rings in the center. A max load bearing on the flywheel side (has more ball bearings than the standard) and a TZ roller bearing with the stock angled pto gears. I have no fancy razzile dazzile machine work done to the cases. I have never herd of anybody else doing it ethire. Call matoon machine see what they say. They cnc billit cases for 18mill + stroker cranks. I don't think their billit cases have machined o ring groves. Josh Quote Link to comment Share on other sites More sharing options...
AKheathen Posted November 6, 2009 Report Share Posted November 6, 2009 yah, i'm building a 4mill with maxloads in the center, as you need to rebuild the crank in order to replace them, and an outter bearing failure puts alot of leverage on the centers, that could force you to have to replace them as well. if you are worried about the binding, there is a twin row self-alligning bearing in the same 305 series. it's made for just that purpose, but not much side loading. search for the 1305 vxb bearing. Quote Link to comment Share on other sites More sharing options...
Koolguyson Posted November 6, 2009 Report Share Posted November 6, 2009 LOL I knew as soon as I read the first two sentences you were talking to TSS. No comment on the floating crank since I have never messed with one. But...if it ain't broke, why fix it? If our 200hp twins can get by with o-ringed crank bearings...I think you would be fine too. Side load really isn't an issue anyway when you have TZ bearings/straight cut gears. Quote Link to comment Share on other sites More sharing options...
lt1bird Posted November 6, 2009 Author Report Share Posted November 6, 2009 (edited) I know what you mean, but those guys do a ton of stuff to eek out every little bit of power..... single ring pistons, balanced crank, lightweight flywheel, light weight clutch etc... again, it might be a bit over kill but its what they are all about. max performance/long gevity, super smooth runing... My 535 runs real sweet on the street but it would be nice to have less vibs...but going from the 535 to the 485 alone will reduce a bunch of vibes due to the shorter stroke... I was thinking of machinng the cases per thier spec and make up my mind about the crank setup after.... I do not think the bering would spin in the case with a little yamabond... the baering is a slip fit over the crank not pressed on, this will allow the crank to spin more freely and let the bearing catch up... again, splitting hairs but say its worth 1HP down low... for a pretty simple change that 1hp is basically free...... Edited November 6, 2009 by lt1bird Quote Link to comment Share on other sites More sharing options...
No Limit Powersports Posted November 6, 2009 Report Share Posted November 6, 2009 There is no side load if your running straight cut gears. And the TZ (roller) style bearing should only be used with the straight cuts, because the bearing isnt designed to take any side load like a ball bearing will. Maxloads have a c clip retaining collar so there is no floating. Quote Link to comment Share on other sites More sharing options...
lt1bird Posted November 6, 2009 Author Report Share Posted November 6, 2009 I think some of you are getting confused with "floating" The floating part from what I understand is that the bearing inner hole is a bit larger than the crank shaft. This is not a press fit onto the crank! It slips on by hand....so at low rpm when the engine wants to rev quicker the crank would spin freely as the bearing would not spin until the bearing eventually got up to speed... sound correct? Quote Link to comment Share on other sites More sharing options...
AKheathen Posted November 7, 2009 Report Share Posted November 7, 2009 i know what your talking about, but i've seen alot of bearings wear the shaft out by spinning in other aplications Quote Link to comment Share on other sites More sharing options...
Koolguyson Posted November 7, 2009 Report Share Posted November 7, 2009 I know what you mean, but those guys do a ton of stuff to eek out every little bit of power..... single ring pistons, balanced crank, lightweight flywheel, light weight clutch etc... again, it might be a bit over kill but its what they are all about. max performance/long gevity, super smooth runing... My 535 runs real sweet on the street but it would be nice to have less vibs...but going from the 535 to the 485 alone will reduce a bunch of vibes due to the shorter stroke... I was thinking of machinng the cases per thier spec and make up my mind about the crank setup after.... Maybe send your motor to a better builder and you won't need to mess with all this junk. Lol, k...that was mean...true, but mean. Also, inertia in a motor does benefit you some. What type of riding are you doing? I also doubt you will see any difference in vibration by going to a 485. A dual ring piston will wear less and seal better. Nothing about a single ring will help with longetivity. Quote Link to comment Share on other sites More sharing options...
lt1bird Posted November 7, 2009 Author Report Share Posted November 7, 2009 a 485 definatly does not vibrate like a 535... 4mil vs 10 mil stroke is a ton. I do street bike riding. The TSS 485 engine is very well engineered.... fully balanced crank...nobody else is doing this probably beacuse they dont care about the vibs on quads in the dirt etc...On street bikes you feel the vibes... single ring pistons have been around a long time, they are much lighter than 2 ring pistons, revs quicker, less drag etc. I agree, might not seal as good but will always make a few hp more.... and get to max RPM quicker. I dont think the shafts/bearings will wear any quicker than any tranny bearing as its got the same setup... Ill let you know how it works out... if I go that route LOL Quote Link to comment Share on other sites More sharing options...
Koolguyson Posted November 7, 2009 Report Share Posted November 7, 2009 a 485 definatly does not vibrate like a 535... 4mil vs 10 mil stroke is a ton. I do street bike riding. The TSS 485 engine is very well engineered.... fully balanced crank...nobody else is doing this probably beacuse they dont care about the vibs on quads in the dirt etc...On street bikes you feel the vibes... single ring pistons have been around a long time, they are much lighter than 2 ring pistons, revs quicker, less drag etc. I agree, might not seal as good but will always make a few hp more.... and get to max RPM quicker. I dont think the shafts/bearings will wear any quicker than any tranny bearing as its got the same setup... Ill let you know how it works out... if I go that route LOL I don't agree that there is less drag/friction with a single ring. One ring does not support the piston like a dual ring does, and as a result the skirt of the piston makes more contact with the cylinder wall. Don't forget that the ring is an essential heat transfering component in your motor. You will experience a lot more heat on the crown of your piston with only one ring. You would be surprised to note that a 4-wheeled device transfers a lot more of the engine vibration than a 2-wheeled vehicle. Look, not to jump on ya here...because I am really just trying to help. But it sounds like you are going off of what you are told, and not what you know. I think it would be best if you called a few of the American companies and see if they can't make you more horsepower for less money. Yeah, I know shipping is a pain in the rear, but I would much rather give my money to USPS international, than TSS (who is insanely overpriced). Quote Link to comment Share on other sites More sharing options...
lt1bird Posted November 8, 2009 Author Report Share Posted November 8, 2009 overpriced? If you add the parts up its not really over priced... dont worry, there is nothing you could say to hurt my feelings. Its all good, always value folks opinions.... Quote Link to comment Share on other sites More sharing options...
Koolguyson Posted November 9, 2009 Report Share Posted November 9, 2009 (edited) overpriced? If you add the parts up its not really over priced... dont worry, there is nothing you could say to hurt my feelings. Its all good, always value folks opinions.... Yup, overpriced. When they buy a china crank, balance it and sell it for 750 bucks (200 less than a FULL billet crank), that is overpriced. When they charge $75 an hour and 20 hours ($1500) to assemble a motor...that is overpriced. When you are paying 1450 dollars for a cheetah cub top end that sells everywhere else for 875...they are overpriced. Or $225 per piston..etc. etc. etc. it goes on and on my friend. However, I did some research for you, and I will PM you some of the things I found out. You would be very surprised. Edited November 9, 2009 by Koolguyson Quote Link to comment Share on other sites More sharing options...
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