TS1 top end setup advice needed

[coaster]

I'm in the process of putting my first TS1 together at the moment. Using an Indian Li150 case modified to big block by CS Engineering and a Mec Eur 58mm crank fitted with a Yam 110mm rod. The engine is goiung in my LiS125 which I want to keep looking standardish and will most likelyt be using one of the new Ron Moss Super Clubmans when they hit the shelves. I'm more interested in torque rather than out and out speed, so looking for any advice as to what I can do to tame the TS a bit. I've just bolted the top end on for the first time with a 2.. base packer without gaskets. The head is an AF Rayspeed item with a 1mm gasket (it was suck to the head with silicone so I left it on) and turning the engine over by hand by gripping the taper, the piston JUST kisses the head as it goes over TDC. Obviously I can fit some base gaskets and or a thicker head gasket but was wondering if there are any other suggestions with my torquey setup requirements?

In also noticed that the boost port is about 2-3mm lower than the top of the transfers, Is that normal, anything to be gained in raising it?

Cheers

Colin

[Darrell Taylor]

an awkward one
as what will work best is whatever port durations will suit the tuned length of the pipe in use the best
for the best pull from the lowest rpm which i think is what ur after then drop the cylinder as low as it will go ,but for the highest torque a higher setting may be better

[wack 63]

One of the most common mods is to machine the cylinder base to lower the transfers and exhaust timing,basically de-tuning it.With using the 110 rod you should be able to pack the cylinder to what ever timings you decide,try to aim for around 125 ish degrees on the transfers ( standards are around the 130 mark) The piston will probably then protrude out the top of the cylinder but by using a thicker head gasket which is safer than a 1mm one anyway,it is just a case of getting the squish right.The "thick" AF heads are probably the best to use as there is less chance of warping although I always alter the squish angle to match the crown better and modify the combustion chamber and they nearly always need skimming to get the squish correct even without a gasket. Raising the boost port shouldn't be needed in your case although I raise them on a fast road tune to the same level as the mains like modern 2 strokes, whether it benefits the motor is hard to tell though. A 30 mm carb should be ample . You could use the port timing calculator http://www.lambretta-images.com/archive/porttiming.php to work things out.

[coaster]

Thanks guys, I'll get the timing disc on it and see what I get. Carb wise I will be using a 30 mm(powerjet version) BGM PWK on an LTH manifold through a filter

Cheers

colin

[Darrell Taylor]

wack ,howd you arrive at those timings, degree wheel ,rolled both ways ?

[storkfoot]

Col, I ran my standard TS1 for a year with a 2.5mm packer and a 110 conrod, on a Taffspeed Road expansion pipe and static timing. I'd never had a TS1 before. It was really smooth and pulled readily from low down.

After a year's hard riding I was changing the piston rings and decided to put it back to normal with a 3mm packer. I prefer it now. It's little burbly at low speeds around town (30mm PHBH) but nothing to make you not enjoy the ride.

I have the AF head. I'm just getting it reprofiled to the Asso piston as, whilst it's run well, the squish was a bit variable around the circumference.

The good thing about the 110 rod, is that you can play around and see what works for you

[Darrell Taylor]

wack ,howd you arrive at those timings, degree wheel ,rolled both ways ?

you said (With using the 110 rod you should be able to pack the cylinder to what ever timings you decide,try to aim for around 125 ish degrees on the transfers ( standards are around the 130 mark)

?

the reason i ask is there quite a bit off what transfer timings are on a ts1


transfers are difficult to measure correctly 1mm on transfer is approx 5 degrees yet 1mm on exhaust is around 3.9 degrees

so lowering the cylinder has an effect of tuning the cylinder if you weigh up the pro,s and cons

[coaster]

Quick update, The top end is now 'together' fitted with a machined Avanti head




Squish is 1.3mm with a 2.5mm packer and 2 thick (1mm ish) Ron Moss base gaskets (one either side)


Timings worked out as 130 transfers and 180 exhaust


Still a bit undescided about the exhaust but leaning heavily towards the Avanti when it eventually arrives.

cheers

colin

[soullad]

Col, just a thought, and in no way a criticism, if you look at that last pic do you think the fat ring of the Avanti head will act as a barrier to the forced air of the flywheel. If you dremelled that ring between the fins on this side, would you not increase both the surface area of the head and increase air flow through the fins to the rest of the head? On an Avanti barrel this probably wouldn't be called for, but on this?
Also does the exhaust port region suffer from any reduced cooling effect or does the bigger head simply act as a sink, drawing heat away?

[coaster]

Col, just a thought, and in no way a criticism, if you look at that last pic do you think the fat ring of the Avanti head will act as a barrier to the forced air of the flywheel. If you dremelled that ring between the fins on this side, would you not increase both the surface area of the head and increase air flow through the fins to the rest of the head? On an Avanti barrel this probably wouldn't be called for, but on this?
Also does the exhaust port region suffer from any reduced cooling effect or does the bigger head simply act as a sink, drawing heat away?

I can see your logic Mike but I'm assured by the fact that AF are supplying these for use on the RB250 so I don't anticipate any problems for my lowly TS1. There have been other big heads used on Lambrettas (MB did one) which did away with the cowling alltogether. Either way I'll be using a CHT