62t cylinder exhaust port timing
- Thread starter Mouthfulloflake
- Start date
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
Just to update this thread.
and to give some hopefully useful info to the databank here.
Ive since had 2 more 62t 701 cylinders.
ALL had the same sleeve over hang like in the pics.
I assume these were early 701 raider cylinders, and have a casting for higher port timing.
but came with 61x sleeves.
so.... My next question.
I guess I need to measure sleeve thickness and figure the safe MAX bore size.
I plan to run with the 83mm sudco pistons ( cheap)
will continue to update as I get it done.
and to give some hopefully useful info to the databank here.
Ive since had 2 more 62t 701 cylinders.
ALL had the same sleeve over hang like in the pics.
I assume these were early 701 raider cylinders, and have a casting for higher port timing.
but came with 61x sleeves.
so.... My next question.
I guess I need to measure sleeve thickness and figure the safe MAX bore size.
I plan to run with the 83mm sudco pistons ( cheap)
will continue to update as I get it done.
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
so then 84mm is max?
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
Bump for ENDO
Endo
Non-tree hugger
- Location
- Northeastern Indiana
Thanks, that helps alot. Time for a 61.5xt!!!
6M6 Exhaust on a 701 Cylinder?
Bringing a thread back from the dead... I am trying to do this on the Cheap as you Might have already guessed, it is for a wave runner 3 seater so performance is pretty much not that big of issue. I see both the 701cc and the 650cc yamaha use the same exhaust gasket so a little porting must be possible on the 6m6 Exhaust, What kind of dremel tool head should I use to do this; should I even bother if 701 exhaust tube is bigger?? thx from a noob
Bringing a thread back from the dead... I am trying to do this on the Cheap as you Might have already guessed, it is for a wave runner 3 seater so performance is pretty much not that big of issue. I see both the 701cc and the 650cc yamaha use the same exhaust gasket so a little porting must be possible on the 6m6 Exhaust, What kind of dremel tool head should I use to do this; should I even bother if 701 exhaust tube is bigger?? thx from a noob
Last edited:
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
just bore the manifold out to match the gasket.
a carbide rotary file is what I have used, the aluminum cuts very easily.
a carbide rotary file is what I have used, the aluminum cuts very easily.
Thx MFF! I am doing the 6m6 case as well to fit the 701 jugs, Anything else I should be doing while the bits still sharp? In the Conversion thread I read It does not breath that well... Imagining lots of aluminum everywhere
http://www.x-h2o.com/threads/1665
converting a 650 to 701 mod
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
you can research some case porting on 61x cases, I would assume the same theories and areas need attention since the design is very similar.
waxhead spoke highly of an angle milled intake manifold to tilt the carb to straighten the flow in the 6m6 cases.
waxhead spoke highly of an angle milled intake manifold to tilt the carb to straighten the flow in the 6m6 cases.
Damn got my reeds today guess 701 are not interchangable
but the 6m6 intake reed block looks better airflow wise, it's tilted! Hmm Do I shave the Intake side of the 6m6 case looks like alot less material ! Thx again!!
Nuklear6
I Dream 10' Surf!
Take a good look at the top sides of the exhaust port compared to the sport port temp. the top of that exhaust port in that sleeve is def flatter then other reg 61x cylinders i have seen or ported. I build alcohol burning single cylinder engines for race car and when we change the shape of the top of the exhaust port (with little to no change in port height or timing) from rounded to flat, it changes the rpm range by a good 200 but sometime up to 300 rps on the top. It actually makes about 2 or more horsepower peak on the dyno as well. However it def effect the power and rpm on the bottom which for a jet ski application which does not have lower gears to shift into would not be good for bottom end. This all poiints to another reason why 62t/64 cylinders are indeed more for high speed running couches and why 61x is def the #1 for surf
- Location
- baldwin ny
they do not use the same exhaust manifold gasket!!!
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
the 62t cylinders I posted pics of came out of raider 701 boats, they have sleeves that are identical to the sleeves in a 61x as far as I can tell.
#ZERO
Beach Bum
- Location
- Florida - U.S.A.
The exhaust roof height is 2mm higher on the 62T sleeves and there are some other slight differences as well; http://www.x-h2o.com/threads/21863
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
I think we have been thru all of this before, BUT..
I thought these cylinders had been resleeved with 61x sleeves, until I bought 2 more 62t 701 cylinders, and they all had the same sleeves.
does the sport port template raise the roof height 2mm on the 61x kit?
because that template lines up perfectly with these sleeves
I thought these cylinders had been resleeved with 61x sleeves, until I bought 2 more 62t 701 cylinders, and they all had the same sleeves.
does the sport port template raise the roof height 2mm on the 61x kit?
because that template lines up perfectly with these sleeves
- Location
- tampa florida
i measured my 61x 39.80 and 62t 701 was 39.11 and 62t 760 was 37.59 so 62t 701 is close but the 62t 760 is at 2.5mm higher and the 62t 701 sleeves are thick you can bore those to 84 to 84.5 safe
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
yeah, my memory is terrible!
But this is about how the difference that I remember measuring a while back, I recall it was way less than 2mm.
But this is about how the difference that I remember measuring a while back, I recall it was way less than 2mm.