After I bought my Strada a year ago, I noticed it had an S stamped on the crankcase which led me to check the cam timing and pistons to see if was a sport engine or just the cases. Long story short, it turns out it has 366 (375) Sport pistons and an L5 cam. Also has the NLM ignition setup.
What I'd like to know is what tangible difference this would make over a standard Sport. All I've seen is that it would "make a useful performance increase" which means what? I had a 3½ Sport back in 1980/81 but have had many other bikes in the intervening years so it's impossible to make a direct comparison. The bike goes very well but I'm wondering what might be reasonable to expect.
Thanks
Howard
L5 cam characteristics
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Galligaskins
- Posts: 41
- Joined: 01 Oct 2024 19:28
- Location: Loughborough, UK
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Morini Jen
- Posts: 375
- Joined: 12 Jun 2022 18:49
- Location: Warwickshire U.K.
Re: L5 cam characteristics
If you type L5 cam 375 into the search box at the top of the page, it will give you 69 matches. Plenty to read there.
Forum member 72 degrees has a great deal of experience with these things. The thread about his Forgotten Era Hill Climb bike runs to thirteen pages...
viewtopic.php?f=34&t=3812
Forum member 72 degrees has a great deal of experience with these things. The thread about his Forgotten Era Hill Climb bike runs to thirteen pages...
viewtopic.php?f=34&t=3812
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Galligaskins
- Posts: 41
- Joined: 01 Oct 2024 19:28
- Location: Loughborough, UK
Re: L5 cam characteristics
Thanks Jen,
I have previously searched the forum and the wider web for info. There are lots of references to the L5 on the forum but very little about the effect the cam has.
To pull what I've found together:
72 degrees has observed that his L5/375 has significantly more urge in the midrange and that it would rev to 9000 (redline on the 250 tacho that's fitted), Meanwhile 123Morini found it lost power at around 8000 and Smotorboy found peak power at 7800 with power falling off fast after 8000.
It seems strange that the L5 is widely held in high regard yet there is so little mention of what it actually does in terms of on the road performance.
Mine does seem to mirror the above though. Outright top speed seems a little down, but it gets there quickly and holds it despite headwinds or gradients.
I have previously searched the forum and the wider web for info. There are lots of references to the L5 on the forum but very little about the effect the cam has.
To pull what I've found together:
72 degrees has observed that his L5/375 has significantly more urge in the midrange and that it would rev to 9000 (redline on the 250 tacho that's fitted), Meanwhile 123Morini found it lost power at around 8000 and Smotorboy found peak power at 7800 with power falling off fast after 8000.
It seems strange that the L5 is widely held in high regard yet there is so little mention of what it actually does in terms of on the road performance.
Mine does seem to mirror the above though. Outright top speed seems a little down, but it gets there quickly and holds it despite headwinds or gradients.
Re: L5 cam characteristics
There are the L5 and the L5 II ! The last one is a bit more lively (mounted in the First Camel 501 I think). I have that one in Rocinante (motor early 501 Camel original). Dulcinea wears a 501 bild up from diferent Motors ( Camel and Excalibur parts) I guess it has a normal L5.
Allthoug the Motor of Dulcina was lightend: clutch, primario, con rods, pistones, rockers and it weights 30 kg less, Rocinante raise easier the revs and it is faster
The top speed surely is dued to the half fairing she wears but the behavier of the motor, I gues is an issue of the cam, allthough it's dificult to now because of diferent air Filter and escape Systems...
Allthoug the Motor of Dulcina was lightend: clutch, primario, con rods, pistones, rockers and it weights 30 kg less, Rocinante raise easier the revs and it is faster
The top speed surely is dued to the half fairing she wears but the behavier of the motor, I gues is an issue of the cam, allthough it's dificult to now because of diferent air Filter and escape Systems...
Re: L5 cam characteristics
Rocinante with her original 350S motor gave me 120 km/h at 6000 revs. Witth the the 501/L5II and the same lying Veglias it shows almost 140 km/h at 6000 revs!
Re: L5 cam characteristics
I must confess that I have only ridden my 2C/375 with L5 cam once this year (to warm it up for an oil change when I thought I was taking it to the Isle of Man [1]) 
Bear in mind that this engine also runs higher CR (no base gaskets) and PHBH28s, so more variables than just the cam timing.
I wouldn't dare rev it to 9000 rpm these days as the vibes are getting extreme lately. This is partly due to being in a 2C frame with just the 3 point front engine mount I think, but I suspect the bottom end is long overdue a rebuild.
I have another 350 engine with recently (well several years to be fair) rebuilt bottom end with timing side roller bearing conversion, reground crank and new rods. Unfortunately i started to rebuild it again two years ago to fit a 'new' L5 cam and a couple of new gearbox bushes I had machined. Sadly, however, I have lost the motivation to continue with it as my fingers are too arthritic and eyes rheumy to do much intricate spanner twiddling these days. I suppose I should throw it at Benjy - if I can find all the little bits.
[1] That's whole other story.
Bear in mind that this engine also runs higher CR (no base gaskets) and PHBH28s, so more variables than just the cam timing.
I wouldn't dare rev it to 9000 rpm these days as the vibes are getting extreme lately. This is partly due to being in a 2C frame with just the 3 point front engine mount I think, but I suspect the bottom end is long overdue a rebuild.
I have another 350 engine with recently (well several years to be fair) rebuilt bottom end with timing side roller bearing conversion, reground crank and new rods. Unfortunately i started to rebuild it again two years ago to fit a 'new' L5 cam and a couple of new gearbox bushes I had machined. Sadly, however, I have lost the motivation to continue with it as my fingers are too arthritic and eyes rheumy to do much intricate spanner twiddling these days. I suppose I should throw it at Benjy - if I can find all the little bits.
[1] That's whole other story.
Re: L5 cam characteristics
Just fitting an L5 cam to a standard 3½ engine doesn't really improve things in my experience. The engine isn't really held back by any one feature. I just ended up with a big flat spot between 5000-6500 rpm and a motor that pulled about the same at low revs and high revs. It was much more willing to rev though.
However when I improved all the other stuff; bigger carbs, gas flowed heads and rubbers, bigger valves, bigger pistons, higher compression, less restrictive exhaust and air filters, lightened crank, con rods, rocker arms and valve spring caps then the L5 cam realised its potential. Lots more bottom end pull, not great between 5000-6500 rpm then much more pull from 6500 to an indicated 10000 rpm if you had no mercy.
So I guess the answer to your question depends very much on what else you do to the engine.
I am told the factory produced more than one version of the L5 cam, based on when I bought it (new) I think I have the first version.
My partner has a 3½ with a Strada cam and its definitely nicer to ride with more flexibility than the one with the L5 but if you pushed the Strada engine to its limits (in practice we never do) it would be left behind on the straights. Its just as fast around the corners, which is perhaps what the 3½ is all about.
However when I improved all the other stuff; bigger carbs, gas flowed heads and rubbers, bigger valves, bigger pistons, higher compression, less restrictive exhaust and air filters, lightened crank, con rods, rocker arms and valve spring caps then the L5 cam realised its potential. Lots more bottom end pull, not great between 5000-6500 rpm then much more pull from 6500 to an indicated 10000 rpm if you had no mercy.
So I guess the answer to your question depends very much on what else you do to the engine.
I am told the factory produced more than one version of the L5 cam, based on when I bought it (new) I think I have the first version.
My partner has a 3½ with a Strada cam and its definitely nicer to ride with more flexibility than the one with the L5 but if you pushed the Strada engine to its limits (in practice we never do) it would be left behind on the straights. Its just as fast around the corners, which is perhaps what the 3½ is all about.