58 or 60mm crank?

[alanscottj]

I'm looking at buying the crank for my TS1 build and have noticed that you can get either a 58 or a 60mm. Which one would I be needing for the TS1? Tia

[Knowledge]

The Ts1 is designed to work with a 58mm stroke, so the answer is 58mm.

However, the most common upgrade for the TS1 is to substitute the 58mm crank with a 60mm item. This increases the capacity by a few Cc's. It should give an increase in torque, which is always welcome. But be warned, if you increase the stroke, you will need to think about the porting, and where the top of the piston emerges from the top of the barrel.

It is not a straight swap.

[psychedelicropcircle]

Either or, I use a 60/110 in a TS and I understand It to be less harsh on the big end bearing due to the angle of travel. Also increases CC.

[alanscottj]

The Ts1 is designed to work with a 58mm stroke, so the answer is 58mm.

However, the most common upgrade for the TS1 is to substitute the 58mm crank with a 60mm item. This increases the capacity by a few Cc's. It should give an increase in torque, which is always welcome. But be warned, if you increase the stroke, you will need to think about the porting, and where the top of the piston emerges from the top of the barrel.

It is not a straight swap.

Thanks Martin, I'll be keeping it simple, 58 it is then

[coaster]

The Ts1 is designed to work with a 58mm stroke, so the answer is 58mm.

However, the most common upgrade for the TS1 is to substitute the 58mm crank with a 60mm item. This increases the capacity by a few Cc's. It should give an increase in torque, which is always welcome. But be warned, if you increase the stroke, you will need to think about the porting, and where the top of the piston emerges from the top of the barrel.

It is not a straight swap.

Not straight forward but with a longer conrod as well it gives scope for playing with port timings by using combinations of base and head packers which can vastly help to alter the power delivery to suit you needs.....it is a bit of a mine field though

[Lambretta Sash]

It depends on how you approach fitting your cylinder tbh, if it's a quick bolt together then it would be 58 x 107, if you're planning to get best out of kit then maybe 60 x 110. There's plenty of info on here to give you a clue to a fast reliable lambretta

[shocky]

It depends on how you approach fitting your cylinder tbh, if it's a quick bolt together then it would be 58 x 107, if you're planning to get best out of kit then maybe 60 x 110. There's plenty of info on here to give you a clue to a fast reliable lambretta

I agree and no disrespect to anyone whos posted but maybe if you contacted a tuner with experience of all the variable's they could give you a better understanding of what you can/could achive buy using what crank/rod/packer

[Muppet]

Either or, I use a 60/110 in a TS and I understand It to be less harsh on the big end bearing due to the angle of travel. Also increases CC.

110x60=1.833333333333333
107x58=1.844827586206897
107x58 closer to 2-1 ratio

[eden]

Either or, I use a 60/110 in a TS and I understand It to be less harsh on the big end bearing due to the angle of travel. Also increases CC.

110x60=1.833333333333333
107x58=1.844827586206897
107x58 closer to 2-1 ratio

that's why I prefer 60 x 115 or 62 x 115

60 x 115 is close to 2-1 and 62-115 is closer than 107 x 58

Its not only about the big end, having a less steep angle reduces ware on the barrel too and theoretically produces less heat as the angle isn't forcing the piston and rings as hard against the barrel wall, it pushes hardest against the inlet side 90 degrees BTDC

For the orig poster:

increasing stroke as already said increases CC but the main factor it has if you keep TDC the same place on the barrel is to increase transfer timing and exhaust timing, On a TS, using 60mm stroke can make the transfer timing a little too long so you are best cutting a recess into the head so that you can run the piston 1mm higher in the barrel at TDC to keep the transfer timing the same as it would be with a 58 stroke.
On a piston port barrel the longer stroke has the opposite effect on inlet timing, it makes it shorter, again if you run TDC to the same position.
to run the barrel at the same position as with a 58x107 if you was using a 60x110 you would need to pack the barrel up by 4mm, that's because you have 3mm longer on the rod and 1mm longer on the stroke, ( the other 1mm on the stroke is 1mm further travel down the barrel, so due to this you need to make sure what ever piston you are using doesn't hit the crank case at BDC, not that many pistons are long enough to do that anyway when using a 60 stroke.

Just throwing a longer stroke in an engine with out doing some porting to a planned set of durations can and often does work in that it produces more power but mainly only due to the increase in CC, but using a longer stroke and also porting to a planned set of durations and areas makes a much bigger increase in power.

one other thing to consider is that if you do pack the barrel so that the piston sits at the same height in the barrel at TDC as it would with a 58x107 that when the piston is at BDC the bottoms of the transfer and exhaust ports will be higher than the piston crown and the result in that is turbulence in the barrel near BDC, so if you do it like that you should lower the bottom edges of the ports by 1mm if using a 60 stroke.
if you don't pack the barrel and or cut the head you will have the piston traveling too far up the barrel at TDC and it may well hit the head!


decisions decisions......

[storkfoot]

Just to share my experience as someone who had always wanted a TS1 200 or 225 but, until about 5 years ago, had never had one.

I also always work on a "Keep It Simple Stupid" basis (no fancy electrics with me) but I always strive to have good quality components in my engines.

As regards the crank in my TS1 225, I went for Indian GP200 webs with a quality Japanese 110 conrod and bid end bearing (a Kawasaki KE175 in my case as it didn't need the webs machining). Why you may ask?

Well, over the course over the last 5 years, I have messed around with different packers (2mm to 3mm) to see the different effect on performance. I never wanted a balls out racer and I haven't got one but I have got a genuine 20bhp TS1 that is reliable. I have no regrets.