Ignition timing 125H?????? Assistance please!

Lambertini era singles (125 and 250 - half v-twins)

Ignition timing 125H?????? Assistance please!

Postby themoudie » 02 Oct 2015 17:55

Good evening,

Having removed the flywheel and stator plate to renew the cam belt and put it altogether, I thought that I might have the timing incorrectly set and that this would account for the lack of performance above 60Kph in 6th gear, as described in my previous opening message thread. I invested in an Acuspark timing strobe and following the instructions had it fitted up to the 125H after warming the engine through and the results have mired me further. :oops:

With no mechanical tacho working, I used the inbuilt tacho in the strobe and at a steady 'fast idle' of ~1,500rpm the ANT mark on the flywheel is ~3° to the left of the central 'dot' on the top edge of the crankcase. I increased the rpm to ~6,000 and the ANT mark remained in the same position, neither moving to the right or left of the upper crankcase mark in the strobe light? :? I thought from reading the 'blue' manual that I should see the ANT mark re-align itself to the upper crankcase mark before reaching~6,000rpm.

Mystified, I spoke with Stuart at NLM, who was courteous and helpful, but suggested that I might have more experience than he with the 125H! :shock: "If only!", was my retort. Stuart suggested that I check that when the BMS mark on the flywheel aligned with the upper crankcase mark, the engine was indeed at TDC, as he thought that the valve timing might be 'out' by either a "half" to "full" tooth, rather than the ignition timing. However, when the BMS marked is aligned with the upper crankcase mark, I indeed have TDC. I suggested that maybe a transducer was not working, but Stuart thought this "unlikely".

I intend to move the stator plate anti-clockwise, slightly, so that the ATM mark aligns itself with the upper crancase mark, rather than appearing to be ~3° retarded before TDC when running at ~1,500rpm. But I still can't get my head round the lack of variability in the timing of the spark. With this strobe I can set an advance value to a tenth of a degree when viewing the marks, but I'm not sure how this helps when setting the ignition timing. :oops: As you have guessed 'electrickery' is not my forte.

Thank you for taking your time to read another tale of woe.

My regards, Bill
User avatar
themoudie
 
Posts: 72
Joined: 13 Jan 2007 21:24
Location: Perthshire

Re: Ignition timing 125H?????? Assistance please!

Postby EVguru » 02 Oct 2015 19:29

I think that the absence of any change in timing does indicate a faultytransducer or pickup.

If you send me your address I'll see if I have a good spare transducer to lend you. If it's the pickup, I'll first have to actually go and look at one of my 125's to see exactly what setup they use!
Paul Compton
http://www.morini-mania.co.uk
http://www.youtube.com/user/EVguru
EVguru
 
Posts: 1457
Joined: 01 Aug 2006 11:13
Location: Luton

Re: Ignition timing 125H?????? Assistance please!

Postby themoudie » 02 Oct 2015 22:43

Aye Paul,
Thank you for your very generous offer of assistance, I have PM'd you.

My regards, Bill
User avatar
themoudie
 
Posts: 72
Joined: 13 Jan 2007 21:24
Location: Perthshire


Return to Singles

Who is online

Users browsing this forum: No registered users and 1 guest