Scooterotica

Thanks for the replys so far, it seems to be the right choice of direction for me to take at the moment. Money is a bit tight, but I love to tinker around with a project to tests me skills and if I can do this to get a bit more oompf, on a tight budget I should have enough in the kitty for a new exhaust too!
Surprised at the interest in this conversion/post and its good to get some positive feedback, from folk in the know, who have been their and done it, or still are!

Obviously it depends on the holes in the barrel aswel,I never did look at the timings on mine but you shouldnt find it hard getting that info.Im surprised not many bother with this anymore,they just go for off the shelf kits but if you do as much as you can yourself,it can work out a pocket rocket.Im sure the cylinder head on mine was based on a 150 not a 175.

id say this conversion was one of the best ever for a lambretta and that inc the TS1......... why well you can use it as a standard oversize conversion be it with a few mods or a near 18hp screamer if needed, go the long rod route it just makes things easier any size carb from 18mm upto 34mm can be used as well same with pipes does depend on tune though im saving my TV barrel for the day i buy a lammy again

scoothappy wrote:Hey
you need a 2mm packing plate with that piston and a tv rod. works great!

Roadsign and a drill and file
I am with Shocky, I picked up a TV barrel just for the day when all the 200 cases have gone.

The suzuki piston has a compression height of 32mm, a standard lambretta piston is 39mm giving a difference of 7mm.

Based on a standard 107mm rod on a standard barrel you would need to remove 2mm off the top and 5mm off the cylinder to account for the 7mm in the above equation.

If you use a tv rod thats 116mm then you have an extra 9mm, less 7mm for difference in compression height = 2mm which accounts for the 2mm packing plate.
Indian gp cases and spanish cases can be upto 1mm longer aound the spigot area and may only need a 1mm packing plate .

The yamaha rd400 rods are 115mm so a 1mm or no packing plate may be required.

Good Timings
Exhaust - 170 deg
trans - 130 deg
inlet - 150 deg


Smiffy

Where did those timings come from?

From my ikkle red book

Inlet you may say is low but Ive had good umph out of this set up and done many over the years

Sure thing but if your gonna use a Jap piston,you may aswel give it some work to do or just stay with a 175.

shocky wrote:id say this conversion was one of the best ever for a lambretta and that inc the TS1......... why well you can use it as a standard oversize conversion be it with a few mods or a near 18hp screamer if needed, go the long rod route it just makes things easier any size carb from 18mm upto 34mm can be used as well same with pipes does depend on tune though im saving my TV barrel for the day i buy a lammy again

Sorry about the quality of the image...it was a lot worse before Tony O'Brian rescanned it, etc for me (Thanks). But it does show a nice curve. with 14bhp from just past 6k peaking at 17.7 and it held that with a nice flat plateu for a while...it was still holding 14bhp at 9k. This was the shortened 150 barrel and 107mm rod conversion.

On the topic of the crank I want to use a TV or Yam rod, now I have seen the rods being sold as a kit to be assembled into your own webs.
But not advertised as a complete crank, anyone know any differant?
How easy do the webs part has anyone rebuilt thier own before, I presume you need use of a press and knife edges to balance etc.