LCGB Forums

Clubmate has a Cento 100cc, apart from Jimmy'ing it off a cliff are there any easy upgrades to give it a few more mph?

Boring out to 125 helps. It hardly transforms it into a race bike but it gives it a bit more oomph!

Reed valve-TZR Piston, add boost ports, alter port timings, bigger carb

dscscotty wrote:Reed valve-TZR Piston, add boost ports, alter port timings, bigger carb

"easy upgrades", I guess that comes down to the definition of 'easy' and whether this also suggests 'cheap'

I'd choose the "off a cliff option" but I may be able to talk him into a 125 rebore. Thanks Chaps.

Didn't Cass do a barrel kit?

A number of years ago I got asked to look at a Cento that a local pal had bought. Although it had not long since been rebuilt, it had issues that needed resolving and was still dog slow once those issues had been resolved. Realistically, it was a 40mph cruiser with 45 being its max speed. As a quick upgrade we sourced a J125 top end and I gapped some new rings so that it was all as should be, fitting a new J125 exhaust at the same time and rejetting accordingly.

The result from the above was a bike that then cruised at 45mph and topped out at 50mph (same as my Vega with Starstream top end... but at considerably less revs than a Vega does at the same speed). Whilst this might not sound like any great increase, it make enough of a difference on the road that you didn't need to thrash it to death all of the time and it gave a fighting chance of keeping up with modern traffic speeds in some scenarios, whereas the Cento top end was seriously under-powered for use today (putting rider in danger).

The 60s Performance Tuning Manual gives clear instructions/info on the Cento 100-125 procedure.

Adam