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RT195 with original Taffy expansion- gearing recommendations

Posted:
Wed Nov 08, 2023 11:38 pm
by Bidsy
I’m after bit of advice from you guys if possible please. I’m building a small block RT195 ( piston ported) and have an original Taffy expansion to go with it plus Italian LI150 gearbox and 46 crown wheel. Could anyone recommend what final gear ratio I should be aiming at for a good touring setup (13 stone and a bit of luggage ) I want to be able to sit comfortably on a motorway at 60mph but still have a bit left in the tank of overtaking. Also recommendations of carb size. Thanks
Re: RT195 with original Taffy expansion- gearing recommendat

Posted:
Thu Nov 09, 2023 12:03 pm
by Rich Oswald
I have a Taffy Mk 4 on my Muggy 225. I had an Italian GP200 box on at first, so same FDR ratio as LI150 (5.2) but went to 19/46 (4.8) FDR which I stayed at when I went 5 speed. Pulled great for me but i'm only 11 stone. Defo go at least 16/46 but may pull 17/46 which is what I have on my RT225 reed (5speed). May be trial and error.
Rich'
Re: RT195 with original Taffy expansion- gearing recommendat

Posted:
Thu Nov 09, 2023 11:58 pm
by Bidsy
Does the Original Taffy produce its power high up or low low the power range?
Re: RT195 with original Taffy expansion- gearing recommendat

Posted:
Fri Nov 10, 2023 2:51 am
by GP Kevo
If it's their road pipe then the power is pretty low down with the peak power at around 7,000 RPM. The road exhaust is in two parts not including the silencer. The down pipe connects to the exhaust flange. Then that connects to the main expansion pipe with two springs
If it's like a JL4, really fat, one piece and with a really long stinger leading back to the silencer, then it's their race pipe. That exhaust makes power much higher up in the revs.
Hope that helps.
Re: RT195 with original Taffy expansion- gearing recommendat

Posted:
Fri Nov 10, 2023 12:03 pm
by Rich Oswald
Bidsy wrote:Does the Original Taffy produce its power high up or low low the power range?
Low down the power range. It's a touring pipe with plenty of torque.
Re: RT195 with original Taffy expansion- gearing recommendat

Posted:
Fri Nov 10, 2023 6:44 pm
by Bidsy
Look like I have the road version, So am I right to assume it delivers power similar to that of a box pipe and would be better suited to a FDR of around 4.9 rather than 5.2?
Re: RT195 with original Taffy expansion- gearing recommendat

Posted:
Fri Nov 10, 2023 11:06 pm
by Rich Oswald
Bidsy wrote:Look like I have the road version, So am I right to assume it delivers power similar to that of a box pipe and would be better suited to a FDR of around 4.9 rather than 5.2?
IMO yes.
Re: RT195 with original Taffy expansion- gearing recommendat

Posted:
Wed Nov 15, 2023 1:14 am
by ULC Soulagent
Me personally I’d settle for 5.2 fd with the expansion pipe
Everyone is different though so case of suck it n see
30 phbh delly as well
Re: RT195 with original Taffy expansion- gearing recommendat

Posted:
Wed Nov 15, 2023 11:59 am
by hullygully
I had Taffy exhaust for years, got bored with hitting the invisible wall, then changed to a Franny tourer

, then upped to a super tourer
