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definitely a couple of finger ports in there ;)

Must be possible to fit some V force reeds in there? I know the tohatsu the reed blocks are very small, V force style would give you more area if you can fit them in

Haven't tried the new style but the old rubber hub ones were more desirable. Not sure if there's actually any difference in blade profiles

Agree with mike, and try not to keep the engine at a fixed RPM for too long, when you're at 2000 rpm just move the throttle up and down slightly to vary revs

That's seriously cool!

Not got photos of it back, those just came up on my facebook. They belong to a guy called Michael Graves in New Zealand

https://i.ibb.co/DzC0Fkv/48423154-2084714748240790-2900687248041181184-o.jpg
https://i.ibb.co/jDY016J/48430279-2084714878240777-4814422089844916224-o.jpg

https://i.ibb.co/Y23t4ZZ/238844.jpg

Seen a few photos, can't find them now though! Here's a link to some https://www.geckotrailers.co.uk/single-axel-to-750kg/thunder-cat-and-zapcat-trailer

You get special wedges for that - https://www.specialistsmallcraft.co.uk/products/outboard-transom-wedges
Not sure if they’d fit your engine but worth asking

That's a really neat solution, like that a lot

looking good

Aquarius quality isn't so great, they fall apart after a few years but they are probably the fastest thundercats out there. Ceasar build quality is good, as is Infanta, I've been impressed with both....

They should spin silently and with no play, it's usually fairly obvious when they've gone, they deteriorate quickly and make a lot of noise

Does anyone have the dimensions for the exhaust flange on a 70CES?
https://preview.ibb.co/mb2uTH/IMG_5815.jpg

Does anyone have the dimensions for the exhaust flange on a 70CES?
https://preview.ibb.co/mb2uTH/IMG_5815.jpg

I don't mean shimming it so the gears are too close together, just taking the tolerance closer to what it should be from factory.

Hey Jake, lapping looks like the way to go thanks mate. Did...

Alright, I've never tried shimming the gearbox but heard you can shim it tighter to gain some rpm. Not sure if there's much to be gained by balancing the gears seen as the diameter is relatively...

I meant I can't add anything such as lwp or a bullet point.
The gearbox works fine but shimming it to reduce the tolerance can help reduce friction. There's regulations for the bullet and skeg...

Standard Yamaha 70ces gear case, can't change the shape of it by adding lwp or point etc. Was going to balance the gears and re shim the gearbox at the same time

Hi Jeff, I'd heard of that being done, not tried it but I might try some back to back tests to see how it performs
cheers

Wondering what folk do to their gearcase to improve performance?
Was thinking of stripping all the paint off as it's quite thick and putting on one thinner coat. It's used it salt water or else I'd...

I would avoid the cleaver shape if you're running the prop fully submerged. The more blade area you remove the less pitch the prop will have

Couple good props here - https://www.facebook.com/forgemarine

You can read my build thread with my old tohatsu 50, we get 63.6mph with that motor now on a thundercat with an 18p Mercury Chopper -...

If it's the same as the Tohatsu 50D2 which I believe it is, rev limiter comes in at 5850. The crank shaft is pressed, it's generally not recommended to remove the rev limiter without welding the...

That's fast now!

There's a guy with a 90 short in Aus, he's still tuning it but says it works well. I'm tuning my 70ces, still some work to do but at 67mph just now. I don't believe anyone has had 80mph out of one of...

Cool build :cool:

Always liked that phrase, the costs seem to increase exponentially the faster you go, I only paid £750 for the engine, the porting + other mods were £1200



There's only 1 fuel pump on the...

haha, its hard to go fast for cheap!

I run super unleaded here in Scotland, 97 RON

Hey Fred,

after all round power, engine is ported with 90hp carbs. The TSR head ive got has removable chambers so I could draw up some new ones and have them CNC'd
I've heard 34cc is decent, TSR...

Anyone have experience testing different CC head chambers on the ces?

I think they're the same diameter, just different jetting. The jets in the 60 carbs might even suit you better

Looks really sharp in blue!

Wouldn't have thought a bigger powerhead would fit under a 50hp cowl, I suspect it's just a tuned 50hp

That's a really smart looking solution, nice work!

Does anyone know of any smaller lower units that will fit the 70ces? It's quite a lot bigger than the 50hp, I think you could fit a 14" diameter prop on the 70

Also maybe worth thinking about a...

i believe the F50 gearbox will fit the 70, it fits the 70ces, have a look here - http://www.thundercatinflatable.com.au/forum/showthread.php?3493-70CES-Yamaha-Infanta-Thundercat-Build

Anyone know what motors use 12 spline props? Any 75hp OMCs?

I can't believe that you would get near 3 cylinder (70ces) performance from a 2 cylinder. When you're tuning the 3 cylinders it's extremely effective because the cylinders are 120 degrees apart,...

The closer your gear ratio to 1:1 the smaller diameter prop you require (more RPM less torque). Bigger diameter is more efficient in terms of prop slip.

Managed to get a copy of them from a CES book, any tips and advice on timing are always welcome though!

I second this, if Jake tests a prop and says it works on SLT's you'll sell a bunch of them

Is there any reason you would lighten the crank instead of the flywheel?

Anyone got timing link lengths for a yamaha 70? Or if someone with a yam 70 could take photos of the timing links so I can get an idea of the lengths that would be much appreciated

cheers

Thanks Tim,
Seems to be the general consensus - not as stiff as stainless but better than brass.

Regarding material, does anyone have any experience with Aluminium Bronze/NiBrAl? Seems a lot of companies prefer to offer this for casting as opposed to stainless. The strength and hardness figures...

Fantastic, thank you very much! sent you a PM