Lucas Rita advance

baz · Aug 11, 2024

Recently I decided to check the ignition timing on my commando 750 as I hadn't checked it in many years and I felt the timing could be out
I have an Alton starter so no timing marks
I set the motor at tdc and made a mark
And then another at 29° BTC
When I checked with a strobe lamp I found the advance steadily increased until around 3000 rpm where it stops and as revs increased to say 5000 it suddenly advanced again
It was around 30-31° at full advance
There was nothing steady about the advance curve
This was with a Rex's speed shop replacement cdi
So I tried plugging in an original Lucas CDI amp with the same results
Is this normal for Lucas Rita would anyone know?

Britstuff · Aug 11, 2024

Hi Baz:

F.Y.I. / full disclosure, I am no expert, but my limited experience does stretch to setting up the timing a couple of times on my Lucas Rita equipped MKII 850 Commando.

Seems odd to me too. Of course it is a lot of fun trying to watch the advance, while a mate gives her the beans and the bike reverses across the garage floor! I do still have the timing marks on my bike, and to me, (using a strobe light and my MK I eyeball) the advance looked pretty linear.

I hope I am not speaking out of turn, and that others will wade in who have much more experience than me.

baz · Aug 11, 2024

Britstuff said:
Hi Baz:

F.Y.I. / full disclosure, I am no expert, but my limited experience does stretch to setting up the timing a couple of times on my Lucas Rita equipped MKII 850 Commando.

Seems odd to me too. Of course it is a lot of fun trying to watch the advance, while a mate gives her the beans and the bike reverses across the garage floor! I do still have the timing marks on my bike, and to me, (using a strobe light and my MK I eyeball) the advance looked pretty linear.

I hope I am not speaking out of turn, and that others will wade in who have much more experience than me.

My bike doesn't move that much with both wheels on the floor
I can just about open the throttle and use the timing light
I wasn't expecting a sudden jump in the advance!
If I hadn't revved it beyond 5000rpm I would have thought it was all out at 3000

Britstuff · Aug 11, 2024

My mate told me he blipped the bike up to around 6000 rpm or maybe a bit more, while I was watching the advance. The "Mistral Engineering" (i.e. factory correct, Lucas Rita) instructions for Norton Commando (with a standard lift cam) call for an advance from 20 degrees at 2000 rpm, to 28 degrees at 6000-6500 rpm. We did it several times and it appeared to me to be pretty much as it should be, with a linear progression all the way up to 6000 + rpm. Not at all like what you describe. I don't think my mind was playing tricks with me, even with that "super smooth" parallel twin trying to shake itself apart in front of me!

NickZ · Aug 11, 2024

I had a different experience with the advance timing on my 72 Combat that had RITA ignition. Whenever I tried to measure the advance with my strobe, it always appeared that the advance would jump up to a number (~ 40*) as rpm went thru ~4500 rpm. You may find this thread interesting:

Thread 'Combat performance issue - RITA'

Oct 28, 2022

I have been trying to get to the bottom of a performance issue with my 72 Combat Interstate. Performance seems fairly normal in 1st - 3rd gears but in 4th gear the bike does not accelerate like it should, struggling to get past 4000 rpm. I read the thread on this subject posted by @ILLF8ED starting in 2015. As suggested there, I have eliminated fuel flow and valve timing as causes and have moved my focus to ignition timing. This bike, as did ILLF8ED, has the RITA electronic ignition.

What I am seeing with my unit is that when I set it up as specified in the Mistral Engineering...

It's long but al lot of RITA info in there.

I was never sure if the jump in advance was really happening or there was something wrong with my strobe set up. I do know that there was an issue with the RITA reluctor I was using. I believe it was somehow modified from standard Commando configuration, and it was not triggering symmetrically, leading to jitter .
As you will see if you get to the end of that thread, I finally gave up on it and put in a Boyer, which resolved the jitter and allowed for a stable carburation setup.

baz · Aug 11, 2024

NickZ said:
I had a different experience with the advance timing on my 72 Combat that had RITA ignition. Whenever I tried to measure the advance with my strobe, it always appeared that the advance would jump up to a number (~ 40*) as rpm went thru ~4500 rpm. You may find this thread interesting:

Thread 'Combat performance issue - RITA'

Oct 28, 2022

I have been trying to get to the bottom of a performance issue with my 72 Combat Interstate. Performance seems fairly normal in 1st - 3rd gears but in 4th gear the bike does not accelerate like it should, struggling to get past 4000 rpm. I read the thread on this subject posted by @ILLF8ED starting in 2015. As suggested there, I have eliminated fuel flow and valve timing as causes and have moved my focus to ignition timing. This bike, as did ILLF8ED, has the RITA electronic ignition.

What I am seeing with my unit is that when I set it up as specified in the Mistral Engineering...

NickZ

Replies: 114

Forum: Norton Commando Forum

It's long but al lot of RITA info in there.

I was never sure if the jump in advance was really happening or there was something wrong with my strobe set up. I do know that there was an issue with the RITA reluctor I was using. I believe it was somehow modified from standard Commando configuration, and it was not triggering symmetrically, leading to jitter .
As you will see if you get to the end of that thread, I finally gave up on it and put in a Boyer, which resolved the jitter and allowed for a stable carburation setup.

Just read back through the post
I'm now wondering about the pickup
The reason I was checking the timing was because of low speed performance
My bike will pull to over 7000 rpm in the lower gears quite easily
I was just surprised to see the advance jump

Lucas Rita advance

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