L-5 Cam Question for the LSR ?

[smotorboy]

Hello all,

Does anyone have a Dyno chart on an L-5 equipped motor ???

I just need the Torque & Horsepower RPM peak numbers....

I have a chart from when my bike was a stock K2....

Torque peaked at about 6200 rpm.

Horsepower peaked at 7800 rpm and fell off fast above 8000 rpm...

As changing the cam on a 350 is a BFD,,, it would really help if have those numbers to help the LSR project move forward...

Robert in California

[morini_tom]

Can't help you on the peak figures but...

It is possible to modify your cases to enable you to change cam without splitting them in future.

Machine the clutch side crankcase/cam bearing abutment so that you can push the cam and clutch side bearing through. Add a groove to retain the bearing with a circlip instead.

When you want to change cam it's then a little more straightforward (clutch and primary side cover off, pushrods out, timing gear off and then push the cam through, using a drift made up to also stop the cam followers dropping out.

I modified my 501 like this (admittedly never got round to changing a cam in situ, but I did it to protect against the 2+2 or L5 debate)- I stuck with 2+2

Tom

[smotorboy]

That is a really good idea !

Supercharged engines very are sensitive to the amount of valve overlap they have and it might take a try or two to find just the right cam grind that really works well.

Thanks !
Robert

[smotorboy]

Let me ask this in another way...

For those of you that have or have ridden an L-5 equipped bike,,, at what rpm did the power start falling off???

Robert

[72degrees]

Let me ask this in another way...

For those of you that have or have ridden an L-5 equipped bike,,, at what rpm did the power start falling off???

Robert

Too many variables perhaps. My 2c 'grinalot special' has a 375 motor with L5 cam, 28mm carbs, NLM stainless 2:1 system. It still has the 250 mechanical tacho but will pull to the 250 red line. During the last bottom end rebuild, many years ago, the L5 replaced a 2+2. It's so long ago I can't remember just how it went on that. I've never had a proper dyno test though and the carburation is still way out in the mid range. Just when I think I've got it right the sun goes behind a cloud. Still, who spends much time at part throttle if they can help it ?

[smotorboy]

Thanks 72degrees,

Pulling to redline is what I need the motor to do....

Robert

[EVguru]

I'm pulling close to 10,000 rpm at Cadwell on a stock Sport cam.

[mgill]

I once took the time to degree an "L5" re grind from
3D in Germany. Turns out it was nothing like the published
numbers for factory L5 but actually a sport cam with 1mm
Higher lift... So you know... Now you have another option
with less overlap....
Ducati Development Dortmund

Mathew

[smotorboy]

I have a re-ground L-5 to replace the M cam in my motor....

I think I'll setup a test rig and check its numbers my self...

A Sports grind would be better to work with the supercharger than an L-5 cam to prevent back-fires...

Thanks,
Robert

[EVguru]

One of these days I will get around to checking some cams.

I have an original 'L' cam as fitted to late Camels and I used to have an original 2+2. I have masters for these on file with Newman Cams.

I'm not convinced that the L is the same as the L5 and I've been told that there was a cam actually marked with L5.

I would have thought that the M cam, which is very simlar or identical in profile (but not base circle) to the 500 cam (in effect a high lift Strada cam) would be well suited to forced induction.

You can of course change where peak torque occours by changing the cam timing. That's standard practice where a stock cam is required by the rules. Even if stock timing is required, you push it to the limit of factory tolerance.

[mgill]

I have an original L5

[smotorboy]

The "M" cam pulls great up to 8000, but then just goes off a cliff ( just as the rolling road chart indicates)....

I'd like the motor to pull hard to 8500 or maybe a little more , but that is all I need...I'm putting enough stress on the bottom end without sky high rpm making things worst.

A perfect cam for me would have no more than a 28 degree Intake opening event with 8 to 10 degrees extra before Intake closing. The exhaust event would also needs more duration .

A Sports grind looks good from the charts.....

IF ANYONE WANTS TO SWAP A SPORTS GRIND FOR THE FRESH REGROUND L-5 I HAVE,,,WE CAN MAYBE WORK SOMETHING OUT....

I will measure the lobes on the cam I have and see what is what...

I also might be able to have it custom cut to keep the Intake opening where it has to be to prevent backfires when on boost...The wasted spark has to occur before the Intake opens else bad things happen.

ROBERT

[George 350]

Hi Robert,

If the cam you have has the right amount of overlap, then as Paul suggests, swinging the cam timing will help you get more power at the top end at the expense of bottom end. On a Morini this is "easy" to do as they come supplied with a vernier belt pulley on the crank. I have no idea how much movement you can get away with on a Morini without piston/valve contact, but I do know that it is the exhaust valve you have to watch. The 1.7 Ford Puma for example has VVT and the published data shows that the inlet cam is swung upto 40° crank, and that for peak torque, overlap is around 32° with IVC at 34°ABDC, while at peak power overlap is virtually 0 and IVC is something like 66°after BDC.
If you were to set the engine at TDC, and rotate the cam counter-clockwise as viewed on the timing side, you should have a pretty good idea how far you can go before contact. ( If you were to close the exhaust valve clearance down first, say tighten the adjuster an extra turn, this would jack the valve down approx 1mm and give you the correct angle leaving about 1mm piston/valve clearance for valve float when you run the correct valve clearance.)
Even if you can only get 10 degrees extra on the IVC number it will help you a lot.
Best Wishes,
George.

[MickeyMoto]

and there me simple ol' me thinking this was an English language forum......

[EVguru]

The "M" cam pulls great up to 8000, but then just goes off a cliff ( just as the rolling road chart indicates)....

Then I'd suggest that something is wrong.

A Dart will easily pull past 9000rpm and Jarl's LSR Dart when much better when he followed my advice to rev it 500-1000rpm higher before shifting.

Apart from anything else, check the cam timing.