when yamaha 61x & 62t cracks ???

[iptamenos]

Wondering when cylinders crack in which cases
is the porting? The bore size? The ignition ? The compression ?
Is necessary the girdled head and if yes what bore size and after.....




:Banane36::Banane36::Banane36::Banane36:

 

[Matt_E]

The weakness is in the casting, not the sleeve - so bore size has nothing to do with it.
61X cylinders are said to have a weaker casting than 62T cylinders, so they crack easier.

 

[iptamenos]

So 61x they want more attention than 62t .

61x 84mm with porting they will need girdled head
but the 62t 84mm with same porting they will not

 

[Matt_E]

Bore size does not matter. The casting does.

A 61X cylinder at 84mm is just as likely to crack as one at 81mm, all other things equal.

 

[iptamenos]

i see
but i had never see 61x at 81mm cracks at any case i mean with pipe or a head or with porting ???

 

[Big Kahuna]

With any porting run a girdled head.

With any drypipe run a girldled head.

All others you can run a non girdled head.


But, A girdled head is kinda like insurance. You dont need it until you need it.

Get a girdled head!

 

[iptamenos]

i have 6 girdled head install both my motors have gr head
but also i have seen motors running for years since 1995 with head ,dry riva pipe and no cracks since today
i have seen motor with 62t crankcase's , head 185 pci no gr ,61x riva cylinders dry pipe with msd working since 2001 since today no cracks and this ,motor works a lot

 

[ryan]

i broke 2 61x cylinders (cracked both of them) so it happens. i always run a girdled head now. both of the cylinders that cracked were just b pipe stock bore stock port 701's.

 

[iptamenos]

??? how does it happend ???

post more info about this motors ?
ignition ,head comp.

 

[Tyler Zane]

you worry to much bro, this is a hobbly. stuff is gonna break. just go with it. a gridle head isnt that much more than a nongridle.... just get the gridle

 

[iptamenos]

you worry to much bro, this is a hobbly. stuff is gonna break. just go with it. a gridle head isnt that much more than a nongridle.... just get the gridle

i think that noone understand i don't want to buy any head
the matter is not me and if i will buy a gridle head

the matter is when you really need a gridle head

i have seen many 61x with nongridle heads no one never crack (different setup's)
the only head that you can find in the market new or used is no gridle head
protec ,riva ,rd and the people buy them and install them with no problem until today
the only one that i have seen crack is 84mm 61x with 210 pci race gas .

 

[capitalcrew]

It's hit or miss whether or not it cracks man. Casting is an imperfect way of forming metal. Not every 61x will crack, and some totally bone stock 61xs might.

 

[QuickMick]

With any porting run a girdled head.

With any drypipe run a girldled head.

All others you can run a non girdled head.


But, A girdled head is kinda like insurance. You dont need it until you need it.

Get a girdled head!

Damn dude, this guy just gave you every answer you need. Just pretend this is all bad info and go run your stock head.

 

[The Penguin]

i think that noone understand i don't want to buy any head
the matter is not me and if i will buy a gridle head

the matter is when you really need a gridle head

i have seen many 61x with nongridle heads no one never crack (different setup's)
the only head that you can find in the market new or used is no gridle head
protec ,riva ,rd and the people buy them and install them with no problem until today
the only one that i have seen crack is 84mm 61x with 210 pci race gas .

huh?

http://www.adaracing.com/personal-watercraft/head-kit-yamaha-701-super-jet-girdled/ya701mhdkit

 

[snowxr]

Any cast cylinder could crack. Modify any 61x engine, and you just have to expect it to crack while hoping it doesn't. I've seen them crack the mounting ears (even stock motors), and crack in half below the exhaust ports (seen more on motors with ported transfers). The 61x cylinder is somewhat thin, and bolting any exhaust to it (extra unsupported weight) puts stress on it. Fatigue over time will eventually win. Get your head out of the sand, and take some advice. Ask a question, expect to get the answer wether you like it or not. Just because you don't want a girdled head doesn't change the need for one. Cross your fingers, buy a lucky rabbit's foot, go kiss the Blarney stone, throw a pinch of salt over your shoulder, and pick a 4 leaf clover. Maybe that will keep your cylinder from cracking, but my money is on the girdled head.

 

[iptamenos]

Damn dude, this guy just gave you every answer you need. Just pretend this is all bad info and go run your stock head.

for your info i don't have a stock head i am using 8mm

 

[Tyler Zane]

lmao....

 

[iptamenos]

huh?

http://www.adaracing.com/personal-watercraft/head-kit-yamaha-701-super-jet-girdled/ya701mhdkit

Originally Posted by iptamenos
i think that noone understand i don't want to buy any head
the matter is not me and if i will buy a gridle head

the matter is when you really need a gridle head

i have seen many 61x with nongridle heads no one never crack (different setup's)
the only head that you can find in the market new or used is no gridle head ====== in Greece ======
protec ,riva ,rd and the people buy them and install them with no problem until today
the only one that i have seen crack is 84mm 61x with 210 pci race gas .

 

[iptamenos]

Thank you all for your informative replies. I kind of got the answer i needed. Even though i was not asking when do i need to change the head, but i was asking what is the reason that the cylinders crack. I believe that because you have more cases of cracked cylinder, it must be the different temperatures, gas and/or usage. Be well all and take care.

Iptamenos.

 

[kevbo]

Its a weak design that is too expensive for Yamaha to fix since they use a permanent mould. One of the A/M shops should get good, inexpensive replacement castings made in China. But then they would have find customers that didnt have a billet fetish.