2 Strokes Down Under

My brother has been building a bike for years and getting nowhere. Originally he was going to put a speedway engine in the frame and build a motard type thing.

On the long weekend we were on a friends property, and they had a hovercraft with a seized engine.

It used a Yamaha Phazer 485 snowmobile engine. We got to talking and figured it might be the answer to some of the issues putting the speedway engine in the bike such as no charging system.

It's an air cooled parallel twin and also has a starter in it. We're thinking of hooking it up to the same Norton gearbox that he was going to use with the speedway engine. It's a pretty compact engine and should have some poke on a simple bike I would think.

But why?

What do you mean "....has been building a bike ..."? Make a frame and then stuffing in a motor?

Why an odd ball motor? Isn't it hard enough to play mix and match and to build a hybrid?

With this snow mobile/ hovercraft engine I would expect 'motorcycle unfriendly' engine characteristics. My best guess would be both of these applications use peak hp at a steady r.p.m. rather than a spread of power needed for a m/c.

Not making a frame... it's an XT600 frame. Why an oddball motor? Because it's available, and "because we can".
Since when did the RD350LC have a "friendly spread of power"

Maybe we can measure the port heights to give us an idea.

WHy not just buy a cheap banshee motor from the states?

you can get stockers in decent condish and big bore strokers in need of a rebuild for cheap

I reckon you should use the 485 snowmobile motor you have! With a bit of tinkering and some good pipes it should be capable of some decent power. Plus you have it... and yes.. 'because you can'!
Look forward to seeing a build thread on this little beauty!

Jeram, any advice on how to get cheap Banshee motors from the States? I'd be up for one of those, could be cost effective?

Hybrid, looks interesting, would like to see how you mate that to an old school Norton gearbox and the chassis you have available.
Heck, this is a "use what you've got" bitsa project, not chopping up an original masterpiece, and not a resto either, so should be interesting to see how you get over the hurdles.

I recently bought a rooted bottom end for an IT250 from the us and posatge was about $260 US. USPS is not ideal for shipping this stuff....

If it came to it how would you register the thing? Is it a case of cross your fingers and hope for the best.

Why couldn't be be registered as an XT600 using the original frame number with a new engine? It's smaller than the original by cpacity, so shouldn't be an issue.

Forget all the negative questions, Hybrid... Build it and cross the bridges as they come! I look forward to seeing this unfold.

OzzyElsie wrote: With this snow mobile/ hovercraft engine I would expect 'motorcycle unfriendly' engine characteristics. My best guess would be both of these applications use peak hp at a steady r.p.m. rather than a spread of power needed for a m/c.

They use a CVT so it don't matter how narrow the band is because it's always in band.

Which bring you to the difficult bit and that is attaching the CVT/gearbox to the engine, as some one stated an old AMC type. Dr Robin Tulie di this with the Tularis. There is a gixxer with a sled motor somewhere on the net

This one never had the CVT as it was attached to a hovercraft, but using a belt primary drive like that, or just an old school primary chain is what we were thinking.