Scooterotica

A little update for Spring...

Motor is going to be crank case inducted so it's necessary to machine the cases and build an intake from scratch. Someone had previously ground down the bump stop, doing me a favor in the meantime.

Rotax Lamby build-036 by PotvinV8, on Flickr

First, I machined a block to match the curvature of the crankcase with the bolt pattern for the intake and the intake port scribed. I will machine the actual intake port when it comes time to finish machine the cases (no need to set up the mill a bunch of different times!)

Rotax Lamby build-037 by PotvinV8, on Flickr

The gap between the case and intake block is actually closer than it appears in the photos. Eveything will get TIG welded up once everything is dry fitted.

Now the fun begins! First task is to make sure the intake tract clears the frame tube throughout the entire travel of the rear wheel. I decided to use a Boyeson reed valve from a KDX 300 to make things easy. I machined off the stock spigot that's used to mount the carb rubber as I'll be using a flange-mount type carb.

Rotax Lamby build-038 by PotvinV8, on Flickr

Rotax Lamby build-039 by PotvinV8, on Flickr

With the carb in place, I decided I didn't like the way things were going, so I switched gears and decided to mount it a bit higher. This allowed me to add a bit of clearance around the floor board support as well as the engine mount lug. It also allowed me to make a new carb mounting plate that will incorporate a throttle cable mount.

Here's the carb attached to the first version of the intake...

Rotax Lamby build-040 by PotvinV8, on Flickr

I simply added a small riser section atop the intake to get it to the point where I was happy with the clearance and location of the carb. That's a 38mm Mikuni Super BN for those curious. Integral fuel pump and adjusts via external screws so it should make tuning easy. Note the added 'ear' on the carb plate that will allow me to machine a hole for the throttle cable to pass through, something I overlooked the first time. Live and learn...lol

Rotax Lamby build-042 by PotvinV8, on Flickr

With the intake welded, it'll take some time to get everything nice and smooth, then it'll receive a bath in the sandblaster. At the end of the day, it will look like one cast piece.

Rotax Lamby build-046 by PotvinV8, on Flickr

Here's the engine as it sits now, though the intake has been welded up.

Rotax Lamby build-041 by PotvinV8, on Flickr

Just waiting for Martin @ Chiselspeed to work his magic on the crank and then it will be time to finish welding and machining the engine.

Oh yeah, received the clutch from Rocho68 last week. Looks spectacular!

Seven-plates to help reign in the power of the 300cc Rotax setup...

Rotax Lamby build-044 by PotvinV8, on Flickr

Rotax Lamby build-045 by PotvinV8, on Flickr

Looking Sweet ,How`s the crank coming on

Martin at Chiselspeed is getting me sorted with a 64mm crank attached to a 125mm rod that I provided. He's been super helpful, a breeze to deal with. I'll post pics as soon as it arrives.

champion ,Glad to see its coming on leaps and bounds

twin peeks wrote:

TED CRUD wrote:

thats a big one ,jetski or mx bike





I have a Bigger Jug to fit

i say
thats a big one ,jetski or mx bike

Its now for sale 84 mm piston 60mm stroke full engine ,selling due to wanting a RT watercooled set up
http://www.ebay.co.uk/itm/300929492785? ... 1555.l2649