Scooterotica

My early Mb/bgm Clubman is 17mm internal diameter. As far as I know, they have remained the same.

Thanks everyone - I also forgot to mention running an avanti head too just to try and keep cool, but that's not made much improvement - clearances are pretty big, 4 thou - tuner checked before he built it up as its running a Yam DT250 piston and he says you can run the bigger clearances with those Pistons.

The ONLY thing left is the pipe ??

Those carb settings seem rich enough to keep it cool..i take it the avanti head was profiled for a yam piston?..

Darrell Taylor has previously commented regards the restrictive tail pipe size on larger cc engines... 4 comment down the page:

http://scooterotica.org/forum/viewtopic ... an#p269927

camel wrote:Those carb settings seem rich enough to keep it cool..i take it the avanti head was profiled for a yam piston?..

Yes had it profiled to suit. But to be honest it was doing the same on a previous AF head that was fitted. If I could weld, and build my own clubman I would, but I don't know anyone that does something so involved !!

Are you experiencing any "pinking"under load?

camel wrote:Are you experiencing any "pinking"under load?

None - which is surprising

Does sound an odd one...good bore clearance..rich jetting..no pinking..so i can see your train of thought for the pipe....
One more thing..after seizing do you remove the barrel?alluminium deposits could replicate a tight bore in places.
Next for me id swap the pipe(altho im still not convinced) for anything you have laying about and try that to prove it out.

camel wrote:Does sound an odd one...good bore clearance..rich jetting..no pinking..so i can see your train of thought for the pipe....
One more thing..after seizing do you remove the barrel?alluminium deposits could replicate a tight bore in places.
Next for me id swap the pipe(altho im still not convinced) for anything you have laying about and try that to prove it out.

Your not wrong - I'm going bald scratching my head as it's definitely a new one on me. Ideally, I'd like to get my hands on Ron Moss clubman , I've had a few and still run one on another almost identical set up , runs brilliantly ( just the insides rattling it's tits off )

Or I'm waiting for the new improved GP50 gori pipe to come into stock at Rimini.

I wasnt convinced by people telling me it's the pipe either but it's literally the only thing left