GT 240 Options

[Rich_T]

I have a Fran Tourer that I used on test, it's in very good condition with TS1 and standard flange. It doesn't have the edge that the race has but if your touring its OK. There is a boss welded on for a Lambda probe. PM me if you're interested

[wintermod65]

It is many years since I was aware of the relationship between the exhaust bleed size & the effect upon the performance. It really is a case of bigger power potential within the top end will require a bigger bleed.

Crudely put, any 'one-exhaust-suits-all' (which suggests 125 cc up to 250 cc plus) is about as likely to be true as Boris Johnson's promises.

Yet these Clubman exhausts continue to be sold, even going through variations of about four or so in some instances, that endeavour to control the noise output by having one size of bleed (tailpipe) that will not only restrict performance of a good top end but actually harm it by heat build up.

I wouldn't mind earning the profits accrued whilst scooterists buy my products whilst actually being the Guinea pigs to finally admit (but not in public or in writing) that a bigger bleed is essential! All bow down & say "Hail Version V!" or whatever will be the latest 'fix'

That's why you have to admire the integrity of people like Ron Moss who makes a Clubman exhaust fit for purpose, rather than support somebody that claims to have almost invented the wheel from their web pages.....

hopefully the ex box st will work in a variety of engine configurations as im not 100% sure which kit to go for next

[Leo]

I had a CST3 on my GT240 and it was very nice.

[wintermod65]

I had a CST3 on my GT240 and it was very nice.

didnt you have seizure issues with your GT 240 as well ? did you ever sort it or did you go with another top end

i looked into the underkickstart pipe from chiselspeed for my gt240 but they recommended the cst 7

after a few more setbacks i think il follow dan from scooterings example an go for a TS1 build .

im just wondering on the feasability of using a 65mm crank to give 250cc ive got GT casings im told theyll accept 64mm cranks without additional work so hopefully a 65 will go in . im pretty sure darrell taylor does a 65mm crank after watching the TType engine video on youtube so might have to get some advice regarding this set up.
im wondering whats the biggest cc i could go up too with a 70mm TS1 barrel using any of the currennt big casings and cranks available ?

.pipe wise im looking at a ron moss ex box st as soon as they return to stock at dealers .

as for the GT kit thats destined for ebay when i can get the scooter back from its temporary home for the last 15 months over in worcestershire

[jonzo172]

Scootering tested an AF 48mm Big Bore which had an outlet pipe over 25mm (inch) without an end can. Looks like AF created them specifically for large cc motors.
Scootering test here...
https://www.scootering.com/scootering-c ... es-part-1/
AF listing...
https://www.afrayspeed.co.uk/pages/part ... rtid=57176

[Warkton Tornado No.1]

Looks like AF created them specifically for large cc motors.

AF listing...
https://www.afrayspeed.co.uk/pages/part ... rtid=57176

IMO the tailpipe is a critical step in the right direction, but I would be surprised if it is a 'quiet' exhaust (unless the pipe commences well inside the 'box itself)

It is a shame that the front cone is not longer with a much shorter 'U' pipe. Considering that batches of the things must be made to a specification dictated by AF, a longer front cone would barely impact upon the price they buy for..

I guess the economies of manufacturing scale will always mean that the best Clubmans are always going to be DIY or cottage industry scale like Ron Moss' or Ralph Saxelby's

[jonzo172]

"As far as I am aware, there never has been, or ever will be, a 'clubman' type exhaust that can have such a large tailpipe & have an acceptable noise level without reverting to an additional muffler."

WT1, The AF would appear to meet your spec whereas the Ex Box has a muffler.

[wintermod65]

so what kind of mods to the ron moss ex box has darrel taylor done to get it to work with a 265 cc then ?

just been watching the you tube videos of the 252cc bike with dan from scootering onboard and noise levels seem acceptable , im not such a purist to be bothered by the looks of .a small muffler .

im certainly interested in an ex box st , ive not seen negative comments and they seem to shift of the shelves quiclky judging by how often various retailers are frequently out of stock

[Warkton Tornado No.1]

"As far as I am aware, there never has been, or ever will be, a 'clubman' type exhaust that can have such a large tailpipe & have an acceptable noise level without reverting to an additional muffler."

WT1, The AF would appear to meet your spec whereas the Ex Box has a muffler.

Having continuously owned Lambrettas since 1973, my understanding of modified OEM type exhausts has evolved through a combination of experimentation, "make do & mend" plus a fair bit of track racing.

Prior to Clubman exhausts, a common practice was to gut the standard box to remove all baffling & have a tailpipe with no intrusion. That process alone yielded performance gains @ the expense of some of the silencing.

A combination of the above with a larger ''U' pipe with larger tailpipe was even (much) better allied to a tuned top end. The result would be getting stopped by the police regularly.

We actually bought the last 70's produced orange Ancillotti 50 mm 'U' pipe exhausts & ran them for a while before also gutting them. Obviously, the performance gains were worth it, but the risk of getting stopped was high.

Therefore, my deeply held conviction is that if the AF big bore tailpipe Clubman is quiet enough (whatever that is ) then it will be stifling the performance compared to an equivalent gutted exhaust. Worse is that there may still be a tendency to gas up causing heat issues.

I'd love to be proved wrong, but doubt that the likes of Ron Moss adds an ancillary silencer for the fun of it.....

I am reminded of the occurrences of passengers melting their RH Doc Martin soles on Clubman exhausts such as Royspeeds. Quite a contrast to a good expansion chamber which will run much cooler

[Leo]

I had a CST3 on my GT240 and it was very nice.

didnt you have seizure issues with your GT 240 as well ? did you ever sort it or did you go with another top end

i looked into the underkickstart pipe from chiselspeed for my gt240 but they recommended the cst 7

after a few more setbacks i think il follow dan from scooterings example an go for a TS1 build .

im just wondering on the feasability of using a 65mm crank to give 250cc ive got GT casings im told theyll accept 64mm cranks without additional work so hopefully a 65 will go in . im pretty sure darrell taylor does a 65mm crank after watching the TType engine video on youtube so might have to get some advice regarding this set up.
im wondering whats the biggest cc i could go up too with a 70mm TS1 barrel using any of the currennt big casings and cranks available ?

.pipe wise im looking at a ron moss ex box st as soon as they return to stock at dealers .

as for the GT kit thats destined for ebay when i can get the scooter back from its temporary home for the last 15 months over in worcestershire

I gave up in the end and swapped the top end.