Bad experience with Wossner pistons...

[Motorrad]

make fun of forged pistons all you want I don't think some of you understand metallurgy at all so I guess you wouldn't understand why cast pistons are better for non nitrous motors.....

I have a degreen in mechanical engineering.. is that enough?

[Foxx4Beaver]

I have a great sense of humor....I made a joke about cast,and then you said "I don't think any of you took classes in metallurgy."....basically saying none of us know what we're doing.I don't need to take a class....I have enough hands on experiance and have seen too many catastrophic failures with cast,and none with forged in the last 32 years.
I felt your words were a little harsh,so I gave back.....sorry if I upset you.

[cobbs]

well thats why i said "i dont think" not i know plus didnt say that untill you TOLD me that "ALL the proof ANYONE needs is right here" basically saying what others know is wrong if its different from your "proof" and i said that because everyone i know whos educated in metalurgy will not use them  and ive seen many failures myself and out of prbably 30-35 failures ive seen only 2 were cast failures both were rider/owner error all the rest ive seen were forged and like i said before 90% of piston failures have nothing to do with the piston but i have most certainly seen forged pistons fail just from expanding and locking up and then taking out the cylinder, con rod and crank i have even seen a case destroyed because the rod bent so bad so lets agree to disagree and i will never bring this cursed subject up again ohh and Motorad you know your more than qualified thats why im confused with your preference well then again its probably because your one of the VERY FEW guys who can achieve 10'000rpm so i guess i see why you would

[Foxx4Beaver]

all the rest ive seen were forged and like i said before 90% of piston failures have nothing to do with the piston but i have most certainly seen forged pistons fail just from expanding and locking up and then taking out the cylinder, con rod and crank i have even seen a case destroyed because the rod bent so bad so lets agree to disagree and i will never bring this cursed subject up again

Haha...agreed.

The main reason guys have problems with forged "expanding and locking up" as you say,is because guys set them up way too tight.I bring this up because you said you're running a Wossner...I am too.On the box,Wossner says recommended tolerence is .0028....that's way too tight!!.I e-mailed one of the guys on this forum that deals with Wossner and builds motors...(he knows who he is)...he said they set them up at .004,and that makes them "happier".I went in between at .0036.After 1 hour of run time,I pulled the motor and inspected the cylinder for any signs of over tightness of tolerences...all good.I did the same thing at six hours,and still good.I'm at just about ten hours now.It is a snug fit,but if I had gone with Wossners tolerences...it very well could've been bad.Hopefully you did'nt go with the .0028.

[RoostiusMaximus]

I'm going back to May 7/11 from when I started the official complaint to Wossner on the cr500 pistons also.
I was working direct with John Noonan

I also added more clearance than the box called for (btw, the old boxes show a tighter spec than the newer)
I ran the first one at .003" and stuck it, ran the same piston again, swiss cheesed with lube holes at .005". The afternoon that I stuck the first one I installed my spare cylinder with a vertex and ran it for a week or more, wfo. hillclimbs, bush, field and didnt fail it, eliminating exactly what I'd faught the wossner dudes about, the tune.

another engine I set it up at .0035", leary after the other sticking and stuck this one also.
during the time it took to get that motor installed i'd built a motor for a customer the same, .0035", he also stuck it.

I ran the .005" one in the winter, on the lake and stuck it once more, but i had a good reason for it that time 
I got it back together at .006-.0065", (depending on where you measured it, it was pretty scarred up) and ran it another 10+ hours until i sunk the dome trying some evil ignition timing this spring.

I failed 6 pistons, some had an intake window cut, all had .020"-.022" ring end gap (these single ring ones need more)

[Foxx4Beaver]

(these single ring ones need more)

Single ring???....is that an older one?....mine has two.

[Brute]

Being a long time racer more as a builder then a rider/driver (except drag racing) ANY piston can and will fail under the right conditions. Anytime you modify and push the envelope you will have failures. Just part of the cost of more power. Cast will work fine under the right conditions and use. As I do not push or modify the internals on my dirt bike like I used to I could probably use a cast piston with good outcome. Not some of the other guys on this site with the mods I have seen! Geez guys! I can?t imagine how insane some of the built bikes on here must be! Reminds me of a friend that had a Hayabusa built for drags that dyno?d at 430HP and was STILL PLATED! He offered to let me ride it and I said ?No.? I am sure if it had been ten years earlier I would have said ?Yes!? and I would have tasted the power. Age and injury does that to you??

[Foxx4Beaver]

I am sure if it had been ten years earlier I would have said ?Yes!? and I would have tasted the power. Age and injury does that to you??

haha...I can relate to that! 

[cobbs]

I definitely set mine loose I was worried about it sticking so far its probably got 15hrs on it and its still running great so I'm probably going to throw the boondocker kit (50hp) on it a see what she does with over 100hp its going to be pretty crazy hope my crank holds

[don46]

I definitely set mine loose I was worried about it sticking so far its probably got 15hrs on it and its still running great so I'm probably going to throw the boondocker kit (50hp) on it a see what she does with over 100hp its going to be pretty crazy hope my crank holds

are you using two nozzles? if not the best you can get out of a boondocker is 25 hp, 5hp per hole and the max holes 5, ( there are some 6 hole nozzles but as far as I know 1 is in my posession the rest are in R&D because they freeze up)so unless your using 2 nozzles you aren't getting 50hp out of a boondocker. you could get 50 out of a cold fusion or boss noss, they are both wet systems whereas the boondocker is dry. Boondocker is a simple system and once you get it set up you don't have to worry about them, the wet systems are a pain, using a regulator does help but still sensitive to bottle pressure.

Also, if your going to run nitrous, do NOT run Vforce reeds, they will disintegrate, i mean literally

[cobbs]

yes I'm using two nozzles into a straight K&N (no airbox) and I'm going to make a little aluminum box to hold the 9.6v battery so I can just plug the charger into the aluminum box without have to remove it I'm still trying to figure out how a clean way to mount the bottle and. I'm using stock reeds cause I previously herd that about the vforce with nitrous unless you have a better suggestion of something I should try using

[don46]

I've used boysen with decent success. When I ran my 500 on Nitrous I used a titanium rod, seen many spit the rod out the bottom on Methanol. 50hp would scare me, not the ride the relability. two nozzles shotting 25hp each will consume a pretty sizeable amount of NOS, you using a 2.5 bottle? Some guys remove one radiator, seems like a bad idea to me, I used 12 oz bottles and change them every pass, they are mounted in front of the radiator off to the shroud side.

[cobbs]

I have a couple bottles and I think I'll try the 12oz bottle too just because this is more for fun than anything and I  don't think I  should get to carried away (plus if I have to we have a refill setup) its also just to feel the power difference it will only be used in the sand doing some drag racing  I would never think of using that much power on the street( my bike is street legal) or dirt with out a seriously extended swing arm like you or a wheelie bar, I'm actually thinking of fabbing up a wheelie bar set up to see what kind of 1/4mile time I could get out of one of these single cylinder beasts I bet I could get LOW 9s maybe faster 

[don46]

by the way, the 9.6v battery is a little weak if the ambient temp is high causing high bottle pressure, I use two 7.2 in series and have never had a problem with this setup.