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The Forgotten Error speed hill climber really is nothing like as quick as my road bike. Everything is the same (PHBH28 carbs on both) essentially, except the cam and a paltry few cc. Or are the 366 pistons higher CR than a Sport? The 2C/375 has a genuine L5 cam. The MoT tester remarked at its test this spring on how responsive it is to the throttle. To be fair the late Phil Smith did the bottom end of the 375. I rebuilt the FE engine and perhaps I made a booboo timing the reground Strada cam - though it seems OK when checked with a degree disc (though only a bit hairier numbers than a Sport).

The 2:1 system is possibly a little restrictive as a result of the bend tweaking,but not that much more than the NLM stainless 350 2:1 on the 375 I'd have thought. Looking at results from yesterday and last year it also seems to be down on speed through the finish at Curborough by over 10mph. The track being only dryish for one run didn't help with speed on to the finish straight, but not that much. Last year it had an OEM type 2 red pickup on whereas it currently has an NLM one. That took some setting up, but it starts very well on it. I suppose I'd better strobe check the timing again in case it has 'slipped' a tad.

So any developments on getting a batch of L5 cams made?

It will be the 40th anniversary of when I first rode at Curborough next year. Perhaps I will make the effort to do a bit of swapping about, in hopes of getting round quicker than I did then on a 1929 Raleigh 350 with hand change.

Well good luck with that. I have to add, though, that the older I get, the better I was...

Ming wrote:Well good luck with that. I have to add, though, that the older I get, the better I was...

There certainly may be an element of 'bottle fade'

It does feel dog slow lately though. I could probably put in a better time on the road bike with just the lights taped up.

I'm pinching that quote Ming!
.

72degrees wrote:I'm pinching that quote Ming!

Feel free, though I doubt I can lay claim to it myself.

Pete,

Paul Compton and myself are able to get some cams reground.

We have data for L, L5, 2+2 so with a few orders can get a batch done.

Drop me and Paul an email and We’ll go from there

Tom

morini_tom wrote:Pete,

Paul Compton and myself are able to get some cams reground.

We have data for L, L5, 2+2 so with a few orders can get a batch done.

Drop me and Paul an email and We’ll go from there

Tom

Will do.

I have one of Pauls L5 cams i bought from him some time ago, I intended to fit it to my 410 flattracker, but i am happy with how the sport cam performs so it can go if your interested, I do think some time on the dyno may help point you in the right direction, both bikes on the same day and you will know where you stand as to each engines output, it will give you a ballpark idea of your fuel ratio also. You may have one near you that knows his onions, or try RJS Superbikes at Mallory Park, Checking your timing advance is a definite first job, and cam timing is the next, and compression ratio is a another factor that would have some bearing on performance, all these things im sure you already know but checking them all on both engines is time consuming. Iv'e been going down on my jetting and getting better response, i run 25mm carbs which do not seem to hold it back, for me if i was hill climbing i would have thought 25's would give you better corner exit speed, how often do you have the throttle wide open to get the benefit of the 28's? I found accurate balancing of the carbs gave me much better pickup speed. Will be interesting to see what you find. Flattrack TT course in Lincolnshire

fastharry wrote:I have one of Pauls L5 cams i bought from him some time ago, I intended to fit it to my 410 flattracker, but i am happy with how the sport cam performs so it can go if your interested, I do think some time on the dyno may help point you in the right direction, both bikes on the same day and you will know where you stand as to each engines output, it will give you a ballpark idea of your fuel ratio also. You may have one near you that knows his onions, or try RJS Superbikes at Mallory Park, Checking your timing advance is a definite first job, and cam timing is the next, and compression ratio is a another factor that would have some bearing on performance, all these things im sure you already know but checking them all on both engines is time consuming. Iv'e been going down on my jetting and getting better response, i run 25mm carbs which do not seem to hold it back, for me if i was hill climbing i would have thought 25's would give you better corner exit speed, how often do you have the throttle wide open to get the benefit of the 28's? I found accurate balancing of the carbs gave me much better pickup speed. Will be interesting to see what you find. Flattrack TT course in Lincolnshire

Good suggestions.

On a speed hill climb (grippy tarmac when dry at least remember) the throttle should be wide open any time you aren't braking, or banked right over, and as soon as possible when you aren't I used to run 25mm carbs originally so I know the difference - for me PHBH28s work. They are perfectly balanced with a mercury u-tube manometer.

I haven't swapped the ignition pickup back or checked ignition timing yet so that is the first strategy.

Definitely interested in the L5 but have you ever fitted it and checked the timing it provides? PM me with a price.

I will have to ask Paul what I payed for it. As i can't remember. It's never been fitted. You are welcome to try it in some case's and see what numbers come up.

Re: L5 cam revisited
Unread postby morini_tom » 06 Aug 2018 06:12

Pete,

Paul Compton and myself are able to get some cams reground.

We have data for L, L5, 2+2 so with a few orders can get a batch done.

Drop me and Paul an email and We’ll go from there

Tom

I understood -apocryphally- that the L5 cam, was really christened an L by the factory, and that there is no such thing as an L5, let alone cams stamped with this. I have seen this stated confidently in the past. Are there 2 different profiles then?

According to the info on the Dutch Morini Club site (translation of a German article from 1995) there are two versions of the 'L5' but only stamped 'L' .The 'hottest' 1988 507cc version would be what I'm after. I have no idea what is in my 375 as I've never seen it but given when it was fitted it may be an L5(1).

There are very definitely two 'L' profiles.

Paul Compton and I undertook a pretty extensive bit of research, sourcing as many original cams as we could, many of them brand new, and me measuring them at work in our protoype engine metrology lab. We now have sufficient profile data to be able to commission cam grinds to the origial specification. If anybody wants a cam then the preferred route is to provide us a donor cam, and we can get it reprofiled with one of the other profiles. You wuold likely end up with a smaller base circle than original, but the lift curve would be corrected for that.

I can't share the measurement data but below is a plot of the main cam profiles (this is knife edge lift at the cam, not valve lift). You can easily see the differences between cams. The two 'L' profiles (red and green) have very similar inlet profiles, but the so-called 'L5' has greater exhaust lift. 2-2 has a similar exhaust lift to 'L' but the greatest inlet lift of all.

Perhaps the most surprising observation was that the 'J' cam (excalibur etc) looks like it's somewhere between a sport and an L. I'm surprised more people don't run J cams. Perhaps they get tossed aside as 'just cruiser cams', but it's be interesting to see how a good sport runs with a change to a J cam.

We also measured some cams from the pre lambertini singles, and it was very very interesting to find that the profile of a 2-2 cam is as close to identical to the setebello as you will ever see. (which doesn't necessarily mean anything, as you would need to do some calcs around the follower and rocker gemoetry to understand what that means in valve motion)

Paul and I are keen to do another batch, so if anyone likes the look of any of these, then drop us a message

Interesting weekend reading for you in any case!

Hi Tom and Paul, I could be interested in an L5 cam. I have a few used camshafts lying around that mostly I don't need. One of these is has no ID letter and is reputed to be L5 remade by someone other than the factory. If I was to donate a cam or two would you be willing to check this unidentified cam for me and/or supply and L5?

Perhaps the first thing I should do is dig out the timing disc and check just exactly what the numbers are for my two engines.