FE frame sizes and weight questions

Hey guys, Husaberg n00b here (not a bike n00b). I'm after a bit of info on FEs and the engines, hopefully you lot can help.

I'm planning to put a rotax 654 engine (bored out to at least 720) into an FE frame. I know it would fit into an FE650 frame. They're fairly hard to find over here for cheap though, but I can pick up a smaller one for a LOT cheaper, if my engine would fit in one that would save me a fair amount of cash. So does anyone know if husaberg used the same frames and just put different engines in, or do the smaller capacity bikes have physically smaller frames?

Second question, anyone know how much a husaberg 650 engine weighs? I know the weight of my rotax lump and I'm trying to get a rough idea for the weight of a finished rotax FE720.

Cheers in advance.

steve said:

Dunno about the weight, but the frames are all the same each year.

Dunno about the Rotax, sorta corrupts the purity of the Berg. What about an LC4 frame? Should be fun though.

Steve

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I want the lightest bike possible, from the info I can find online LC4s are around 40kg heavier. The main reason for using a rotax engine is the reliability. My current bike uses one, it's done over 150,000 miles with nothing more than an oil change every 6000miles or so.

Chas said:

Compared to the Husaberg engine, the Rotax engine is much heavier and will add a significant amount of weight to the bike due to the engine alone. Years ago I weighed my Rotax engine and it was close to 100 lbs by itself!!

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Specs I have for the rotax engine give a weight of just under 44kg with oil and carbs, hopefully mine will be slightly lighter as it's EFI and there's far less metal in a throttle body than in a carb, in theory it'll also end up slightly lighter with the 720 kit. It should be a weight gain over a husa 650 engine of slightly under 15kg, and I could save that by just eating less pies :lol:

For me the extra weight is worth it for the reliability, I need a bike I can ride every day, I usually clock up a bit over 1000miles per week, a stock husa just wouldn't cope.

Stock FE650 = 109kg
109 - 27 (husa engine weight) = 82
82 + 44 (worst case rotax weight) = 126kg which is still lighter than pretty much any similar bike, and still nearly 20kg lighter than the G650 BMW that uses the same engine.