Hi John, make sure you read all sections of the forum, we were chatting on another part of forum and diverted accidentaly the other night into tuning the BIS so i have copied and pasted it in here for you.
Hi Mike and all, good to see you on here, the thing is, the old air cooled 126 are the easiest to mod, as the 500 shared the same engine, and as we all know what was produced for the 500 engine tuning, Abarth and Giananini parts. they do great exhausts, up rated camshafts, modified cylinder heads, Dellorto FZD semi-downdraught carbs (panda head needed) thse have bigger venturis i think 32mm +, which all can be used on the air-cooled it is possible to fit on the BIS with time, pateince and money, as the right manifold is paramount and expensive. you can fit 800cc bores and oversized pistons into the standard 126 engine. Your right in the sense of modding is a skill and that we should do it ourselves, we can weld onto camshafts all we like but there?s something about abarth parts, let me show you this link
http://www.fiat500sport.com/def.asp?l=ENG&sku=19512D610C9 http://www.500mania.it/english/index.html I spoke to middlebarton garage, about a sports BIS exhaust, and of course he said he had never seen one, but again these could be made, the essence of an up rated exhaust is the manifold, and the way the gasses surge out. Another thing I have heard about is oversized valves, and with view on a modified head a panda 30 head cant be faulted,
The panda 30 camshaft is also much better in way of design, and fits BIS
We could ditch the panel filter for a stocking over the carb,
Look at this
http://www.fiat500sport.com/def.asp?l=ENG&sku=1952920C18 Last link I promise
http://pages.zoom.co.uk/blitzracing/tuning.htm Chris Lakin