Scooterotica

I'm confused ..............it doesn't take a lot these days

i've read and read until my eyes bleed and I cannot seem to find any information on the standard TV175 barrels and their differences to the standard LI150 SX150 barrels ..

leaving aside the series 1 TV175 I know that the barrels are slightly thicker measured between the first three fins (Sticky) but thats about it.!

What I want to know is this .
If I fit a series 3 TV175 crankshaft to a series 3 Li150 crankcase with the 116mm conrod and an original TV piston with a 90mm pin centre to crown measurement as per original TV175 ........can I use a Li150 barrel or a SX150 barrel instead of a TV175 barrel and what are the porting differences that I need to be aware of .

Aye, you can use it and the timings will be pretty much what they were on the 150 barrel.

Plug the numbers into eden's port timing calculator but there won't be a massive difference.

I'm a bit confused by 90mm though. Standard pistons have 39mm crown height. Tv175 have a 32mm crown height. Have you got fat fingers?

30mm crown height, hence the 9mm difference between the conrods (107mm and 116mm).

Adam_Winstone wrote:30mm crown height, hence the 9mm difference between the conrods (107mm and 116mm).

Sorry. You're right. 30mm. Just agreeing so there's no confusion.

the most common conversion is fitting the 175 barrel to a 150 case, this was the first go faster mod i ever did to a lammy in the quest for more power and speed, i used the atandard 150 crank so needed a conversion piston, if your using the 175 crank and piston it will be fine, i presume your boring out the 150 to the correct size, to match your piston, if so you should be able to make it work, do you have the 175 head as well ?

I've just done a conversion for someone using a lovely large transfer port TV 175 barrel (apparently there are three different port sizes) and a nos three ring piston, all fitted on a standard LI150 crankcase and using the original TV175 crank, runs as sweet as a nut and a bit more torquey than the 175 conversion that came off.
If you have a TV 175 barrel but without a piston its maybe worth looking at doing a Suzuki 190 conversion, loads more of everything.

wow thanks for all the info fellas . yes I couldn't remember the piston pin to crown height so I put a random number in but I don't know where 90mm came from ? I clearly wasn't thinking lol

I have both Li150 and an SX150 barrels so I'll bore whichever is the better of the two port wise. I would much rather use a TV175 barrel but I've been looking for a year and not seen one for sale anywhere which is why I've decided to go the rebore route.

I just needed to be sure that I wouldn't hit any significant problems with regards the port heights.

I did see one 175 barrel but I am pretty sure it was from the 3x wheeler and I believe they are not suitable .

I'll see if I can get a price for a 150-175 rebore and piston kit thanks all

Scooterdude wrote:I've just done a conversion for someone using a lovely large transfer port TV 175 barrel (apparently there are three different port sizes) and a nos three ring piston, all fitted on a standard LI150 crankcase and using the original TV175 crank, runs as sweet as a nut and a bit more torquey than the 175 conversion that came off.
If you have a TV 175 barrel but without a piston its maybe worth looking at doing a Suzuki 190 conversion, loads more of everything.

Regarding the 3 ring piston, where did you get it as I'm after a set of rings.

fluff34567 wrote:

Scooterdude wrote:I've just done a conversion for someone using a lovely large transfer port TV 175 barrel (apparently there are three different port sizes) and a nos three ring piston, all fitted on a standard LI150 crankcase and using the original TV175 crank, runs as sweet as a nut and a bit more torquey than the 175 conversion that came off.
If you have a TV 175 barrel but without a piston its maybe worth looking at doing a Suzuki 190 conversion, loads more of everything.

Regarding the 3 ring piston, where did you get it as I'm after a set of rings.

A mutual friend of mine and the guy who I did the engine for had it tucked away in his shed, it had been there for many years along with a nos cylinder head marked TV 175.
If your after rings try Scooter Restorations at Nottingham, they should be able to fix you up.

Cheers, I had another source recommendation on another thread but that didn't work out.