LCGB Forums

Please excuse the late night random ramblings... As I don't disbelieve the Cologne (homeboys, schnelle besserung Phillip!) Scooter Centers (shame bout the spellings mind...) TS1 BGM big bore zorst (standard barrel no porting) graphs getting down to a 28 PHBH should be an optimum mpg/dream rally (Cyclone powered) mile munching (not overheating due to tail pipe diameter?) set up, or...? Input proper preciated...! Fanx loads!

Superhooper on here is currently building a TS1 using the new LHS manifold and he is looking to fit a 28mm with a BGM(?) pipe. The idea is to make the GP look close to original (with modded air box), but economical.

I suspect the scooter will make about 17-18bhp, which should be enough to get him to Adria with ease.

I do remember a thread on the pre-crash forum about someone running an iron 240 on a TM24 carb, and I am planning to run my 283 on a 30mm.

The new Monza based conversion from Taylor Tuning is making 35bhp on a TM27 carb.

Perhaps small will be big in 2017

I used a 28 phbh on my series 2 after the 34 vhsb wore out. This was with a NK touring pipe, it still went everywhere flat out but used less fuel and lost a bit of top end but not much.

Post by Andy B.L.C. » Sat Jan 07, 2017 2:12 am

Please excuse the late night random ramblings... As I don't disbelieve the Cologne (homeboys, schnelle besserung Phillip!) Scooter Centers (shame bout the spellings mind...) TS1 BGM big bore zorst (standard barrel no porting) graphs getting down to a 28 PHBH should be an optimum mpg/dream rally (Cyclone powered) mile munching (not overheating due to tail pipe diameter?) set up, or...? Input proper preciated...! Fanx loads!

Carburetor bore has a greater significance dependent upon the design.

It is not true to say that a popular, round slide carburettor punches the same weight as one with a flatter section.

In particular, PWK carburetors have gained some fans within the scootering fraternity, but if you look @ other Forums, you will see that they are extremely popular because their cost, efficiency & ease of set-up make them an automatic choice.

Some on this Forum consider A G Bell’s guides outdated, but they are written competently enough for the layman to understand. In his Two Stroke Tuning book, he details the history of the carburetor's transition from round slide to ‘H’ section & so on.

Conversely, minimum tailpipe bore is something that can be stated as a ‘rule of thumb’, more or less, dependent upon what is being required of the engine. If in doubt, err on the big side (another one of Adam’s chat up lines?) say, Ø25 mm to avoid ‘back-up’/overheating or go small if you want to raise low down torque & never wish to rev out/over-rev.

I ran a TM24 on my Ts1 200 with a Mikeck exhaust for a year, could never quite get the needle correct so ran it rich , switched engines, put a rapido classic 225 with lth reed and BGM clubman in my full frame and the TS1 in my chopper, now running the old faithfull 30mm Amal.

Mate runs a 28 phbh on a TS1 200 and it goes well and great on petrol, uses a TSR Evo

I'm going to a 30 from a 34 on one of my TS1 225 this year. Be sticking with the taffspeed copy pipe

I know of a Monza 225 kit [NOT super monza] producing 30+ bhp with Mikuni TMX27.