Woo! After much arguing and whinging from me, FZR4/6 hybrids are elegible for Bemsee Thunderbikes (on a case by case basis)

So, if you fancy a go at Moto2 on a budget and want to run a 100bhp, 146kg FZR4/6 against other interesting stuff-

http://www.performancefab.co.uk/BMCRC%2 ... 202012.pdf

there's now a series to run it in

Cool..

I might have to get one..

10 out of 10 for the arguing and whinging

i always give into my missus when she goes on 1
anything for a quiet life

Well done that Lady

Good whining skills

146kgs is that wet or dry? I have a lardy bike methinks

146kg must be with oil and a little fuel.

My #1 bike us now well under 140 fuelled and ready to ride.

Well done lady, wonder if Thundersport will let them into FE superbikes?

Noooo, the 100bhp/146kg thing was just an example. There's a power to weight limit in the class and depending on which class you run in it'll be either the 'extreme' class at 1.46kg per 1bhp or 'sport' at 1.81kg per bhp. It's all down to how you want to build the bike, but most 4/6s would be able to meet the 'extreme' power to weight

My 4/6 weighed around 160kg, ready to go (well, with a few litres of fuel), and I think it could have gone a lot lower because I still had the standard subframes and clocks fitted, and other bits and bobs. I think 150kg is doable on a low budget.

It's a good thing, because it means that you don't have to tune the engine to have a competitive bike (because of the power to weight limits!), and you're allowed to detune the engine if you think you can make the bike lighter than it would otherwise need to be (so, if you can get the bike down to 130kg, you're allowed to de-tune the engine to get in under the limit).

I'd set the bike up and see what weight you get then match the power to it.
You might find using a 560 conversion will give a better race engine because it has a shorter stroke. Then have a look at some standard mods if you have any spare in the power / weight ratio.

Evilchicken0 wrote:I'd set the bike up and see what weight you get then match the power to it.
You might find using a 560 conversion will give a better race engine because it has a shorter stroke. Then have a look at some standard mods if you have any spare in the power / weight ratio.

I won't be opening any engines- the whole point of my argument to allow them in was that a 600 engine built into 400 cases is pretty much identical to the standard 600 engine, and I'm doing it on a budget so that means no tuning or go-faster bits, just chassis mods I can do myself.

I'm assuming (optimistically!) that it's making about 95bhp, ish. That means the bike has to weigh 139kg after the race, with fuel. There's still loads of room to manoeuvre with the weight and it's easier/cheaper to make the bike lighter than it is to get more power- it's still got the full loom, charging system and starter fitted!