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Adjustment when building a BEC...

Ash1983 - 30/3/10 at 02:28 PM

Hey people,

First post on here so could well be in the wrong place or asking Q's that already have answers - apologies in advance if so!

I'm looking to start building my Locost 7 (based on Ron Champions book) but am aware that a few/several issues surround the accuracy of his cassis. Bearing in mind I want to have a bike engine in mine (at a guess an R6?), does anyone have any useful advice before I start in a couple of months. Obviously don't want to start cutting it up and re-welding after realising I should have asked the question.

Thanks

alistairolsen - 30/3/10 at 02:30 PM

google mcsorely locost and use his plans instead of the book for a start.

Id leave out all the triangulation in the engine bay sides and top and the lower longitudinal chassis rails until you have the engine in place in its mounting frame and try to achieve one set of members which does as much as possible.

blakep82 - 30/3/10 at 02:31 PM

to be honest, the answers are all in this site somewhere, but i wouldn't have a clue where to look. i think David (flak monkey) has a list of all the corrections on his own build blog site thingy, so perhaps worth asking him?

i don't mean any of that in a cheeky way, i mean, the answers are all on here lol

welcome btw

UncleFista - 30/3/10 at 02:34 PM

R6 ? Is that the 600cc ?

I'd have a good look and research gearbox strength/longevity, usually the weak point of smaller bike engine packages....

smart51 - 30/3/10 at 02:35 PM

I'd think twice about a 600cc bike engine. If you're going to the trouble of making a new BEC, I'd advise nothing less than 1000cc.

Johneturbo - 30/3/10 at 02:37 PM

Welcome Ash

You'd want something bigger than a 600cc i woulnd't fit anything less than a 900cc

600 wouldn't cope with 500kg ish

Doh to slow!

[Edited on 30/3/10 by Johneturbo]

Ash1983 - 30/3/10 at 02:46 PM

Bloody hell...if only everything had such quick responses!

Yeah ideally I want to put a 1000cc engine in but I'm just looking at costs...that said I'm sure someone on here will no doubt advise that the difference i price isn't that great. Very early doors so appreciate the comments.

I'm guessing this Mcsorley drawing/design is what anyone wanting to do the chassis themself should be working from then?

Thanks

iank - 30/3/10 at 02:52 PM

quote:
Originally posted by Ash1983
I'm guessing this Mcsorley drawing/design is what anyone wanting to do the chassis themself should be working from then?

Thanks

http://www.mcsorley.net/locost/drawings.htm

Yes the McSorley drawings are accurate. He also provides cutting/order lists.
Finally there are different versions
(+4 and +442) that add inches for the more generously proportioned builder.

Hugh_ - 30/3/10 at 03:13 PM

I agree 600cc is too small, Fireblade RR 893cc engines are cheap now
http://cgi.ebay.co.uk/1995-HONDA-CBR900RR-R-FIREBLADE-ENGINE_W0QQitemZ320507777307QQcmdZViewItemQQptZUK_Motorcycle_Parts?hash=item4a9fc0911b

big_wasa - 30/3/10 at 04:01 PM

or a zx9, the old zzr1100, rf900 are all cheap and will give just over 100bhp

zilspeed - 30/3/10 at 04:40 PM

quote:
Originally posted by big_wasa
or a zx9, the old zzr1100, rf900 are all cheap and will give just over 100bhp

Ye Olde Zed is 147 bhp

Even the ZX10 (not ZX10-R) is 137bhp with the right carbs / carb tops.

And here's a link of a sub 900cc motor givng it some beans in a Westfield.
750cc actually.

And here's another link.
This time a 600cc Honda engine in a Jedi chassis.
I know, not a Locost, but this and the above clip make the point that sometimes you don't need the full fat engine to do good things.
I reckon that a 600cc single seater might work quite well for me. Our capabilities are far more likely to be compatible than something with the full 160-200bhp modern 1000cc bike engine.

A CBR600 still has 108bhp. A light chassis build would absolutely force you to do it right. No fat.

lsdweb - 30/3/10 at 04:46 PM

Welcome Ash

I have a friend who competes in a 600cc R6 engined single seater, but I'd recommend a 1000 as a minimum for a 7.

When putting my R1 Westfield together, we decided to try to avoid a separate engine cradle to reduce weight (not sure how much this has reduced it by though!)

Here's a photo

[img]http://picasaweb.google.com/lsdweb0/WynEdwardsWestfieldRebuild#5300909525934323234[/img]

Wyn

lsdweb - 30/3/10 at 04:47 PM

Photo!
Rescued attachment header tank install.JPG

lsdweb - 30/3/10 at 04:50 PM

And another photo
Rescued attachment linkage.jpg

Paul TigerB6 - 30/3/10 at 06:18 PM

quote:
Originally posted by Ash1983

Yeah ideally I want to put a 1000cc engine in but I'm just looking at costs...that said I'm sure someone on here will no doubt advise that the difference i price isn't that great. Very early doors so appreciate the comments.

Whilst a 900cc or more engine may initially cost you a bit more, its the fitted cost that you should consider. Take for an example the exhaust - getting an off-the-shelf exhaust for an R1 or fireblade engined car from Aries Motorsport etc will save you loads over having to get one made to fit a 600 etc.

As said, gearboxes and clutches may not last so long and you may struggle with the torque (lack of) with a 450 - 500kg car.

For cost effectiveness, look at the likes of carbed ZX9R, R1, fireblade etc. I sold a 98 ZX9R for around Ł400 a couple of years ago and believe its still going strong with a fellow member now.