61x 62t differances?

[zrtman]

cranks are the same, it's just that the t cases flow better and I believe they have bigger reeds than the 61x cases.

Reply is a little late but.. reeds are smaller on 61x.. 62t is better, seems more intakes available too.

My question is why more people are not running 64x 760 cylinders.. its over 50cc more than the 61x... no replacement for displacement...

 

[Mouthfulloflake]

I wonder that too.

supposedly it has a higher exhaust port, that is rumored to have LESS bottom end, but with 50cc more engine, im not sure thats a DIS-advantage.

I might be running a 760 cylinder before too long.

:cool2:

Reply is a little late but.. reeds are smaller on 61x.. 62t is better, seems more intakes available too.

My question is why more people are not running 64x 760 cylinders.. its over 50cc more than the 61x... no replacement for displacement...

 

[DCRocks]

I am getting ready to build an engine for my blaster with a 760 cylinder.

I was told that if you are sticking with siglne carbs, the 61x cases was the way to go, while dual carbs go best with the 62T cases.

 

[marz831]

I wonder that too.

supposedly it has a higher exhaust port, that is rumored to have LESS bottom end, but with 50cc more engine, im not sure thats a DIS-advantage.

I might be running a 760 cylinder before too long.

:cool2:

I thought the exhaust port height was the same as t clyinders. I thought the only difference is the bore size????

 

[Mouthfulloflake]

Ive never looked at a 760 cylinder so IM not sure.

I think they are the reason everyone tinks ALL T cylinders are lame on the bottom end though.

can some one post a picture of a stock 760 cylinder from the exhuast manifold looking INTO the roof of the exh port?

I thought the exhaust port height was the same as t clyinders. I thought the only difference is the bore size????

 

[marz831]

Ive never looked at a 760 cylinder so IM not sure.

I think they are the reason everyone tinks ALL T cylinders are lame on the bottom end though.

can some one post a picture of a stock 760 cylinder from the exhuast manifold looking INTO the roof of the exh port?

I think the bottom end issue is overplayed, bump the compression and a t cylinder shoud hit nicely............no, actually nevermind, they suck, sell them cheap.

 

[Mouthfulloflake]

not to mention the fact that arent as prone to crack...

but yeah, 62t cylinders SUCK, I would NEVER run one.

I think the bottom end issue is overplayed, bump the compression and a t cylinder shoud hit nicely............no, actually nevermind, they suck, sell them cheap.

 

[keefer]

The 64x 760 cyls have the same port timing as the 62T 701 cyls. They come stock at 84mm with more gusseting on the carb side corners. All Yamaha cyls are prone to cracking. I ran a 760 cyl for years and it cracked as did Toby's. You WILL lose bottom end with this cyl over a 61x port timing setup. I currently have my 61x bored to the limit at 84mm and it hits way harder than the 760 cyl ever did. No comparison IMO, 61x is where its at, hands down. You must run a girdled head to avoid cracking, if you are doing much more than stock. If you want a mid-top engine then go for the high port cyls, if you want better bottom end snap for freeride then go with the 61x.

 

[keefer]

Reply is a little late but.. reeds are smaller on 61x.. 62t is better, seems more intakes available too.

My question is why more people are not running 64x 760 cylinders.. its over 50cc more than the 61x... no replacement for displacement...

The reeds on the 61x are noticeably smaller on the 61x cases. T cases will make better power over all. You might consider making a Frankenstein engine by using 61x cases with a 62t cyl. Several here on the board have set these up and I built one a couple of years ago for a Blaster and with an unported T cylinder. It hit hard and ran strong. Not as good as the T cases with X cyl, but it was a good setup.

 

[Mouthfulloflake]

ok,

the port timing is different on a couple of 701-62t cylinders that I have ( they are identticle to 61x port timing)

so there must be some variance among 62t cylinders?

EDIT:

If memory serves, the couple of 62t cylinders I have are raider cylinders, and they appear to have 61x sleeves in them.
there have been many discussions here about them, and I think the consensus was raider 62t 701s have 61x sleeves.
? I think ?

The 64x 760 cyls have the same port timing as the 62T 701 cyls. They come stock at 84mm with more gusseting on the carb side corners. All Yamaha cyls are prone to cracking. I ran a 760 cyl for years and it cracked as did Toby's. You WILL lose bottom end with this cyl over a 61x port timing setup. I currently have my 61x bored to the limit at 84mm and it hits way harder than the 760 cyl ever did. No comparison IMO, 61x is where its at, hands down. You must run a girdled head to avoid cracking, if you are doing much more than stock. If you want a mid-top engine then go for the high port cyls, if you want better bottom end snap for freeride then go with the 61x.

 

[keefer]

T cylinders are supposed to have a higher exh port. Did you measure with a degree wheel and dial indicators?

Here are the specifications for the 61x cylinder.

90.5° Exhaust Port Opens
121° Transfer Port Opens
179° Exhaust Duration
118° Transfer Duration
30.5° Blowdown Time

Here are the specifications for the 62T cylinder.

87.5° Exhaust Port Opens
120.5° Transfer Port Opens
185° Exhaust Duration
119° Transfer Duration
33° Blowdown Time

http://www.x-h2o.com/threads/21863

 

[Mouthfulloflake]

No I didnt use a degree wheel.

But I measured the distance from top of deck to top of EXH port on 3 different 701 62T cylinders, and all 3 were identical to 61x measurements.

#0 posted the 62t specs ( as you pasted above) as 760 cylinder specs.

 

[keefer]

You got ripped off, send them back for a full refund. I would complain to the management. BTW there is a fly in your soup too.

 

[Mouthfulloflake]

hahahaha

I was pleasantly surprised to see the lower port on these cylinders.

i am unhappy to hear the 760 has noticeably less bottom hit, as I am about to swap to T cases, dual OEM 44s and a ported 760 cylinder.

You got ripped off, send them back for a full refund. I would complain to the management. BTW there is a fly in your soup too.

 

[keefer]

I will run great, just get the compression up to 185 and get a thin .020 base gasket to lower the ports a little. I think you will be pleased with it, just run a girdled head as they are known to be crack happy. I am not sure where to get the thin base gaskets. RD was able to get some at one time but is having trouble finding them lately.

 

[standupwannabe]

I came across this post after doing a search, so I was hoping for some feedback for my situation. I have/had a 62T case/61X cyl (stock bore) motor with girdled head (36cc domes & 180psi comp.) & B-pipe, until I dropped a rod and blew the engine apart last summer (RN SJ). I have been rebuilding the motor with a limited budget, so to save some money, I went to a 62T cylinder.
Here is what I now have; 62T case, 62T cyl (bored out once .050 over), girdled head (35cc domes), MSD, and still the B-pipe.
My question is, since I am keeping my compression similar if not higher (have not checked final compression yet as the motor goes in the ski next week, but I assume it will be @ 180+), will I lose much performance from this set-up compared to what I had previously? The other posts state that the 62T cyl. set-up will not produce power until wide open, but I am hoping (fingers crossed) that it will still pull out of the hole as I still have the girdled head and B-pipe. Any comments are appreciated.

 

[tbaer]

i have a full 61x motor bored .050 in my round nose and it makes ok power. i have an aftermarket head that makes 200psi and some reeds. after my build is done and i get the engine back in i have some dual 44's and an r+d intake, factory b (mod) pipe, jet ski innovations is making me a waterbox, lightend flywheel. i am looking for a msd enhancer i am also going to advance the timing alittle. it should make good power then! i am also running a impros hooker 9/15 for some low-end snap

oh poop i didn't notice this thread is almost a year old. damn i brought it up from the dead!

 

[750SX]

I came across this post after doing a search, so I was hoping for some feedback for my situation. I have/had a 62T case/61X cyl (stock bore) motor with girdled head (36cc domes & 180psi comp.) & B-pipe, until I dropped a rod and blew the engine apart last summer (RN SJ). I have been rebuilding the motor with a limited budget, so to save some money, I went to a 62T cylinder.
Here is what I now have; 62T case, 62T cyl (bored out once .050 over), girdled head (35cc domes), MSD, and still the B-pipe.
My question is, since I am keeping my compression similar if not higher (have not checked final compression yet as the motor goes in the ski next week, but I assume it will be @ 180+), will I lose much performance from this set-up compared to what I had previously? The other posts state that the 62T cyl. set-up will not produce power until wide open, but I am hoping (fingers crossed) that it will still pull out of the hole as I still have the girdled head and B-pipe. Any comments are appreciated.

It shouldn't be as good out of the hole as your 61x cylinder. It will run fine though. If you want to try to get some of your bottom end back run a thinner base gasket to lower your port timing. Just be sure to check your squish after you use the thinner gasket.

 

[sjaholic]

hmmm, i see mouthfull in this thread. he hasn't been around for some time now. i heard he was hit by a car in fayetteville while riding his street bike. hope he's alright.

 

[tbaer]

hmmm, i see mouthfull in this thread. he hasn't been around for some time now. i heard he was hit by a car in fayetteville while riding his street bike. hope he's alright.

mouthfull Last Activity: 12-08-2008 01:21 PM