ada orings,anything better out there

[masterblaster]

ive bought some of that hylomar,high dollar and it wouldnt smooth out easy to a thin consistency evenly. it does stay tacky under really high temps though. I really like yamabond,need to find some more

these black orings have melted and blown on both cylinders at diff times,i really hope the brown vitons do better,or ill have to remeasure and deck the cylinder maybe

 

[D-Roc]

i think it is like 5 bucks a small tube vs. 40 for the 1211 big tube. anyways the racing formula has a solvent in it that take like 5 sec to disolve. as long as put in on and don't touch it your fine. it doesn't need to be even, just coated on both surfaces. 1211 takes time to cure, ultimate blue is ready to go. yamabond, 1211, motoseal are all pretty much the same.

 

[D-Roc]

the brown rings i have seen do look much stronger/better. hope they work out for you but i have had good sucess with the ones from ada.

 

[Big Kahuna]

did you order Viton orings?

 

[masterblaster]

the first order for the black ones,was the part # listed on this site in the mcmaster part # reference guide thread,they suck,the second order was for viton brown high temp orings,we will see how much better they fair

 

[DangerBoy]

There are really only 3 main types of commercially available o-ring materials
yes there are a myriad of other materials

Silicone (orange)
Buna (black)
Viton (brown)
regardless of who you get them from only the Viton or buna are suitable for this application. ( some do have different hardness values)

Contrary to popular belief ,the O-ring is NOT the main seal for the combustion chamber , it is the metal to metal (crush) contact between the sleeve and the head prior to the O-ring, and that is what needs to be prefect.
If you are burning ,blowing o-rings you have a problem other than replacing the o-rings and need to check

cylinder deck not flat
sleeves dropped
head warped
domes worn
surfaces not lapped flat or properly cleaned prior to assembly
excessive squish clearance
chamber bore too close to o-ring land
ect.

OEM Yamaha cylinders are more sensitive than Kawi due to their unsupported sleeve design which is especially hard on heads, add elevated compression ratios. detonation or improper squish clearance to this and the sealing surface doesn't stand a chance

also some heads place the o-ring too close to the chamber , that coupled with too large a squish overheats the o-rings leading to failure

Cylinder heads are similar to other engine components and they do wear out

Hope this helps

Db

 

[D-Roc]

oh come on, new orings will fix it just fine, lol.

 

[masterblaster]

DB, I have checked all these,no warping,everything measures good,the clearance is only suppose to be .003 though right? this might be tough to catch sleeves are even,its blown in diff cylin each time also.this ski has been together for 2 yrs working fine,problem just started.squish is 45 and comp is 180.
would the heat from the cylin melt the crappy buna black orings,or does it take the heat from the cylin escaping to do this? they were torqued to 25 and 35 on the head. why is the oring there if it doesnt hold back the cylin pressure? how would a metal to metal crush seal?
Also is it important to run new smaller orings on the back side of the dome that seal it to the head,I get no water leak up there,but maybe new ones help hold down vibration of the domes in the shell.they seem to fit really tight,how would you tell if the shell or the dome is just worn out?
what kind of orings does ada ship with the head stock?

 

[D-Roc]

i have run no o rings in the top of the domes with no leaks bit that was an accident, and i fixed it. i think the o-rings seal out the water, when i blew an o-ring it would suck in water from the cooling jacket. i don't know for sure but that was my understanding of it. My ski ran great forever and then it started happening and after three times, i brought my cylinders in and my guy decked them ever so slightly and that solved the problem. if both surfaces are true, and the domes have the proper .003 interference fit, it should not blow o-rings. not even with higher compression motors. mine is at 190.

 

[D-Roc]

how hot was your motor running? got good dual cooling working properly? no plugs or kinks?

 

[masterblaster]

yea do have dual cooling ,but I had it restricted pretty good through the winter rides,we ride all yr in Va with dry suits,it started happening after I did that,but it never ran very hot,I diverted the other pisser up the pole and used it for hand warmers.id of felt it get overly hot.I already have the brown vitons installed with 1211 so ill give it one last shot before I get a new head and deck the cyl,not looking forward to spending more $ on this thing

 

[jmeadlock]

dont think its warped and domes look fine,just crappy orings,we shall see how long the brown ones last,whats the beast sealant to use on them?

If you're having exhaust enter the cooling system, it's not the O-ring's fault, you have an issue with the sleeve to dome seal. You could try rotating or replacing the domes... take a good pic of them and post it.