Okay I have a ZX9 engine and am planning a De Dion rear axle my quandry being do I go for the book chassis or the +4? +4 being a straight fit for the axle, standard being, well, standard. I just can't decide and am sick of it now so seeing as you lot are the, well, experts. For any reason at all, will you decide so I can just get on with it and save my sanity

I may be biased (), but I'd go for the 442 option, wide rear standard front

Cheers

Alex

Edit:
Standard nose fits 442!

[Edited on 29/8/06 by ecosse]

Do you have an issue with pie retention? If so, +4. If it makes it easier to fit stuff, go +4. Otherwise +4 could be a problem with a nose cone, as I don't know if one is available.

With a bike engine, you don't need to cut away the footwells to fit in a gearbox. You probably don't need a wider chassis as you will already have more room by not having a car engine.

That said, Bike engines often have to be fitted at a bit of an angle to the propshaft. A wider engine bay will allow you to have the enigne fitted a bit straighter.

If you are having a wide (sierra) rear, then you either have to have wider rear arches, which are commonly available, or have a wider chassis with a wider rear, bonnet, scuttle and nose cone. You will have more cockpit room doing this.

I guess either is good.

If you are following the Mc Sorley plans, I believe that Darren at GTS Tuning does the Fi-Glass for the +4's, as no one was doing any, ie he spotted a niche in the market no one else had filled. Give him a ring. He probably wont have them on the shelf, due to colour selection, but can get you one made.

Not the easiest guy to get hold of. Call his mobile and leave messages. He's a good bloke , despite being a verey busy one!.

Personally I suffer from said "Pie Retention" syndrome. Hence I got a Viento.
Dont make it too big and heavy as bike engined cars go very well when light, despite not having a huge amount of torque. Keep the weight down. Dont make it bigger / heavier than it needs to be.

Ask on the BEC forum as well.

Just my 2d worth.

I would try and get a seat in types of chassis, mines standard and evan though my pie retention ratio is above average i fit ok in it.

Especially in light of building a bec id go for a normal chassis for the weight saving. although to add 4 inch into the horizontal tubes probably wouldnt add that much weight, maybe 5kg at most?.

well, seeing as we have some voices for the +4, i will argue the other corner.

Becs are best light, especially the lower end of the power range, which zx9 is. A standard chassis will be slightly lighter, as will most of the fittings. I dont believe its such a problem for big people to get in, it just limits your choice of seat. I use non seat at all, cos its lighter that way.

The zx9 should fit in to a standard chassis fine, mine certainly did, and straight too. Just offset to the o/s as far as the prop will allow (ie half inch clearance to footwell) Exhaust drops through the side panel. Possibly best to leave out the diagonal til you have it in.

Okay. Thanks all, appreciated as always. I have been dwelling on the weight of the frame and weight saving as a whole and as my body pie mass is very low I think I'll give the standard chassis a bash-y. Wahey it rhymes too, must be an omen

i am 6'2" and around 80kgs, and i rattle round mine now. Need some padding down the sides.

I'm only 5'10 and 67kgs so there's a bit more weight saving!!

lol