Scooterotica

I’ve got a Group 4 barrel I’m playing with at the moment for my road bike , the problem is it just wants to flood or bog out all the time at the bottom end – and stalls if you get to any junction, tried a different jets and different carbs with no difference. Also it’s a right Bum to start – without flooding it . When it does goes and hits the mid-range it does go it’s like a rocket, but soon as you let off it doesn’t want to tick over even with a little throttle. I am running it with standard timing 17 deg and a midweight flywheel with no fins . Maybe advanced retard box may sort it out. Any ideas where to start looking or changes

I’d guess it’s got astronomical inlet timing...have you measured it?

or the choke's stuck on.......

Yep inlet is massive,piston also has more off the inlet side.

You can fit a standard piston back in, but if floor of inlet is still too low at that point...

would fitting a reedvalve help if the inlet timing is so big ?

holty wrote:would fitting a reedvalve help if the inlet timing is so big ?

Yes, would serve as a bit of a ‘patch up’ job to get the motor running cleaner and cure the current issue. But could then risk stifling top-end performance, unless ported to match.

Where do you draw the line though? Might be better to stop now and say: Is this the right cylinder for me?

If not then what will it cost to: a) do a patch up job, vs b) fully sort the issue properly, vs c) sell it and buy a BGM kit...lol

Yep going to give up for sale if any one fancys a bit of tinkering. muggello 205 barrel rm piston mb large head (runs with no cowling) bespoke exhaust goes wrong side .requires a 110 rod with 18mm end ape rod does it. £300. All in will post Exhaust is worth that alone and the head cost me 200.pm me if intrested

I keeping the crank

Just before you totally give up where was the timing set on this beast?