Franzis 1/2 BMW R90S engine

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Tim Marlow

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That looks really interesting. At 1/2 scale it must be pretty big?
 

Tim Marlow

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Crikey Ken, that really is a big lad, isn’t it.
 

tigersteve

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Looking good !

When I was at the Isle of Man TT a long time ago , a guy with an R90s was showing off his bike - he laid it over onto the cylinder head with the engine running and revved it hard ........ The torque was enough to raise the bike upright again !!
A bit of an interesting bike to ride , I had a 100RT in the 80s which was very smooth but had to watch the down shift, if the revs weren't right the back wheel locked up for a second being shaft drive, that gets your attention !!
 

Tim Marlow

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Never ridden a boxer....interest point about down shifting though.
You could get a similar effect when switching to reserve tank on a big single.....most bikes, fuel runs out, pull in clutch, switch to reserve, let out clutch to bump start the bike.....if you did that on a big single you could slide the back for fifty yards. On a single you had to “bump” the back when you let the clutch out so the wheel had enough grip to turn the engine over!
 

therapy

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Yeah, similar torque reaction on big Guzzis. In fact they are still like that where BMW have pretty much designed out the feature on their newer boxers.

Really liking this build btw...

Nick
 

yak face

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This is brilliant ken , it looks fantastic , i take it its a fully moving workable model when done , are you going to put a motor on it ?
 

Tim Marlow

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I’ve just had another look.....I didn’t realise the cylinders were offset. When they’re on the bike you only see one at a time. Great stuff.
 
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Work done on the gear linkage mechanism (and I couldn't resist trying it)
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