Hi, im new to the 400 race world and after a few answers about what ive bought.

Ive ended up getting a 400sp for a rider in this years manx gp. Its quite a tidy bike which is tuned/bdk etc. Trouble is i got a bit too keen and bought a job lot of 2 rrsps and spares that were previously raced.( bought for the fancy bits the main bike doesnt have) one has a 600 motor in and is a runner with sp forks/shock and allegedly the close ratio gearbox? does the rrsp box fit into the 600 ? ive not stripped any of the bikes yet as im busy making the main bike safe for the road circuit.
The 400rrsp has a "knock" after the previous owner forgot it was race shift. he bought a standard 400 motor and i have it ready to sling in. Is the knocking rrsp motor worth anything or worth fixing or shall i just junk it?
like i say i only got the bikes for the decent maxton worked onrrsp shock,forks and a few other shiny bits and now im left with a garage full of stuff. If anyone has a rough price what stuff is worth then id really appreciate any help. all funds raised through the sale would go directly back into the team which backs racers on the road.
thanks in advance
mick

The crank cases from the 600 and 400 are common so the gear clusters should swap ... but I can't say what size the bearings are so it might not be a simple swap.

SP's have a close ratio box, an extra clutch plate and lighter valve train. Short races need a good start and the RR's lower first gear can give an advantage, longer races might be different especially if there are more hairpins.

The 600 engine obviously has more torque and it "might" be the gear ratios won't make the most of the engine. I don't really know the difference between the ratios but you may find the 400's gears are lower to get it revving faster. I realise you'll gear the final drive to the track.

The secret of the 400 is in the handling though, being lighter and carrying more corner speed than their steel framed heavier 600 counterparts.

I will probably bin the 600 motor then and rip it apart and sell the gearbox etc.
all the sp bits will be getting broke and sold after the manx including maxton forks and re-worked shock/bdk ignition etc.

anyone know the usual distance the forks are thru the yokes? these ones are flush and ive never had a race bike where they are like this? might just be trial and error to find a good set up.

I couldn't tell you about set up ... you might find it has adjustable ride height at the rear. That would give a full range of travel on the forks which might prove better for road racing.
It's about the sum of knowledge - road racers need longer travel because the circuits are bumpier.

So what will you be racing then .... a 600 with SP box ???

it has a ride height adjuster on it so i should be able to sort it easy enough.just want a base setting.

Dave will be riding the 400rrsp in the ultralightweight race. between us both weve plenty or IOM experience. no 600 motors allowed..