61x VS 62 T

[Polish jet pilot]

Hi all,

Could somebody elaborate on these two cylinders? I know the first one can be called a single carb 701, the second one is dual carb. Although the displacement is the same(?) these two motors had different specs - what accounted for that? Why would a 61X on top of 62T case be a better choice for FS rather than just purely 62T over 62T??

Thank you for sheding some light on this...

Andrew

 

[WaveDemon]

the ports are lower on the 61x cylinder making the 61x better for low end power. the number of carbs only matter with the case beacuse thats what the carbs bolt to.

 

[cookerq62]

The 61x cylinder came on all 701 sj's & fx1's both on single and dual carb models, all have the smaller exhaust. The 62t came in couches with the big exhaust as either a 760 with dual 44's or a 701 with dual 38's. The major difference as it relates to a superjet is the 61x has port timing better suited for bottom end and the 62t is better suited to topend. Honestly it is hard to tell the difference once there is a pipe on it. The 62t is going to be smoother and the 61x is going to have more snap.

 

[Polish jet pilot]

The 61x cylinder came on all 701 sj's & fx1's both on single and dual carb models, all have the smaller exhaust. The 62t came in couches with the big exhaust as either a 760 with dual 44's or a 701 with dual 38's. The major difference as it relates to a superjet is the 61x has port timing better suited for bottom end and the 62t is better suited to topend. Honestly it is hard to tell the difference once there is a pipe on it. The 62t is going to be smoother and the 61x is going to have more snap.

You mention that 61X came on ALL SJ's and FX-1's...but till a certain year I guess? The 96+ SJ have the 62T cylinder over 62T cases, as I understand??

So while building a freestyle engine I could start off with the 61X as it already has more snap? Or should I go for 62T and port it for bottom end?

Andrew

 

[SUPERTUNE]

You mention that 61X came on ALL SJ's and FX-1's...but till a certain year I guess? The 96+ SJ have the 62T cylinder over 62T cases, as I understand?? Incorrect!

So while building a freestyle engine I could start off with the 61X as it already has more snap? Or should I go for 62T and port it for bottom end?

Andrew

All Superjets have a 61X cylinders on them from Yamaha. The '96 and up years just had a upgrade to the 62T cases w/ dual 38mm carbs, but still used the 61X cylinder.
So stock for stock, the 61X cylinder is the best for bottom end power in a freestyle format.

 

[Polish jet pilot]

I love this interchangeability of cylinders and cases. So what combo's can we get without machining?

1. 61x cyl on 61X cases
2. 61x cyl on 62t cases
3. .....
4. ......

.......

 

[WaveDemon]

any cyl on 64x case
i guess you could put a 6m6 on any case

 

[cookerq62]

The only cases that will require machining are the 6m6 650 cases and it is very minimal. I think most shops charge around $40 to cut the cases. The 62t sleeves are notched to fit the cases. I have seen notched 61x sleeves notched to fit 6m6 cases. You may have to bore the cases for a 61x big bore.

3. 61x on 6m6:27:

 

[WaveDemon]

The only cases that will require machining are the 6m6 650 cases and it is very minimal. I think most shops charge around $40 to cut the cases. The 62t sleeves are notched to fit the cases. I have seen notched 61x sleeves notched to fit 6m6 cases. You may have to bore the cases for a 61x big bore.

3. 61x on 6m6:27:

760 cylinders (64x) will not fit on a 701 case without machining

 

[cookerq62]

760 cylinders (64x) will not fit on a 701 case without machining

Is there such an animal? I have a set of 760 cylinders that is stamped 62t and fits in a 701 case.

 

[WaveDemon]

Is there such an animal? I have a set of 760 cylinders that is stamped 62t and fits in a 701 case.

yep, I just sold a 64x case.

 

[cookerq62]

I thought the 64x case just had dual pulse lines for the dual carbs? I'm confused now.

 

[Polish jet pilot]

I am glad I started that thread. It seems that although almost everybody is quite knowledgeable it is good to refresh our memory from time to time....

I was looking at a brand new SJ 2008 and on the engine it says 64V - what is that???

 

[Liquid Graffix]

I have a set of 760 cylinders that is stamped 62t and fits in a 701 case.

the stock 760 cylinders are marked 64X
(you can double check it by looking on the microfish on the RIVA site)
it may be that those cylinders have been bored???

as far as cases,

-6m6 are 650 cases and can be machined as stated by some of the other members to accept the 701 cyl.
-61X are 701 cases, but they have the down draft manifold and came with a single carb.
-62T are the side draft cases that were for the dual carb set up.

63N are also 701 cases and 64X had the 760 cylinders. (both side draft cases)

The cranks are interchangable from the 650s to the 701s so if you are swapping into newer cases just replace the seals if the crank and bearings are good.

 

[WaveDemon]

the stock 760 cylinders are marked 64X
(you can double check it by looking on the microfish on the RIVA site)
it may be that those cylinders have been bored???

as far as cases,

-6m6 are 650 cases and can be machined as stated by some of the other members to accept the 701 cyl.
-61X are 701 cases, but they have the down draft manifold and came with a single carb.
-62T are the side draft cases that were for the dual carb set up.

63N are also 701 cases and 64X had the 760 cylinders. (both side draft cases)

The cranks are interchangable from the 650s to the 760s so if you are swapping into newer cases just replace the seals if the crank and bearings are good.

fixed

 

[Freakrider]

stock 760 cyls have 62t stamped on them....62t cyls were modified into 760 by Yamaha with different sleeves and specs...

 

[Kennay]

the stock 760 cylinders are marked 64X
(you can double check it by looking on the microfish on the RIVA site)
it may be that those cylinders have been bored???

as far as cases,

-6m6 are 650 cases and can be machined as stated by some of the other members to accept the 701 cyl.
-61X are 701 cases, but they have the down draft manifold and came with a single carb.
-62T are the side draft cases that were for the dual carb set up.

63N are also 701 cases and 64X had the 760 cylinders. (both side draft cases)

The cranks are interchangable from the 650s to the 701s so if you are swapping into newer cases just replace the seals if the crank and bearings are good.

All the 760 cylinders still have 62T on the bottom at the base.

 

[GIL]

just go Lamey and be done with it.

 

[steveyz250fpilot]

just go Lamey and be done with it.

Lamey PV to be specific.:twak:

 

[GIL]

Lamey PV to be specific.:twak:

lol