Misfire under power

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Bjay
Posts: 9
Joined: 19 Apr 2022 22:50
Location: Teignmouth

Misfire under power

Post by Bjay »

Hi folks, Bev bought a Strada 8 months ago and we haven't been able to get it running properly since. Initially it had a charging problem which Benji diagnosed as incorrect wiring. I connected it correctly so charging was restored. Rev counter wasn't working so I disconnected the loom to the RC. Ultrasonically cleaned the carbs and re built with new seals and gaskets. Checked ht leads, changed plugs, reset float heights, nothing has made a difference, it misfires badly under load. I did notice the ignition rotor has been making contact with one of the pickups. Does anyone recognise these? I reckon that's the next thing to try. I've got the carbs close with vacuum guages, and it's running same temps on both exhausts. It revs ok while stationary. Help!!
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Strada pickup
Strada pickup
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MickeyMoto
Posts: 2415
Joined: 22 Nov 2008 17:41
Location: Even further oop North

Re: Misfire under power

Post by MickeyMoto »

What an odd pickup. What is the ignition system?

Look here to see a standard pickup:

http://www.morini-riders-club.com/forum ... f=4&t=6992
dunk 1
Posts: 208
Joined: 25 Oct 2007 18:16
Location: cumbria

Re: Misfire under power

Post by dunk 1 »

That looks like the nlm "performance!" pick up to me - I think there is information on it in somewhere in the library - if you can't find it I am sure I have a copy of the instruction set up somewhere.
Duncan
dunk
Steve Brown
Posts: 1390
Joined: 12 Nov 2007 23:44
Location: Leicestershire

Re: Misfire under power

Post by Steve Brown »

Yes, that's definitely the Nlm pick up. It shouldn't come into contact with the rotor but it dies need to be as close as you can get it. If it's been hammered it may be past its best now.
All donations to the rest home for old Camels, Leicestershire.
70sbikes
Posts: 96
Joined: 13 Nov 2014 11:44
Location: Melbourne Australia

Re: Misfire under power

Post by 70sbikes »

Looks the same as my NLM series 2 pick up. When I set mine, I used a small piece of paper to set the air gap so it was equal on both sides. Contact probably explains the misfire.

Image
Bjay
Posts: 9
Joined: 19 Apr 2022 22:50
Location: Teignmouth

Re: Misfire under power

Post by Bjay »

So, does anyone have one of the pickups I can at least borrow or buy to prove this is the problem please? We're looking at Mdina part number 46.05.65 model no M460565 to replace the whole assembly , if this is correct for a 1974 Strada.
Bjay
Posts: 9
Joined: 19 Apr 2022 22:50
Location: Teignmouth

Re: Misfire under power

Post by Bjay »

Bugger, replaced NLM system with black morini pickups and matching transducers. Same problem.☹️ . Valve clearance check tomorrow, new ht leads, cam timing, anything else I can think of.
Steve Brown
Posts: 1390
Joined: 12 Nov 2007 23:44
Location: Leicestershire

Re: Misfire under power

Post by Steve Brown »

Have you checked the resistance on the source coil? This is the one inside the flywheel and on the stator plate. If you put a multimeter across the green lead from the stator and the stator earth/backing plate or white lead if it has one, then you should get a reading of somewhere around 200 ohms. Genereally it's accepted that anything below about 180 ohms is too low. That will mean you are getting low energy supplied to the transducers. You can also get a high or even very high reading on that coil, depending on exactly how it's breaking down. They do get a bit flakey now they are 40+ years old but they can be replaced. You could maybe borrow a known good stator plate from a local member?
I mention this as I couldn't see it mentioned on your posts yet, maybe you've been there already?
All donations to the rest home for old Camels, Leicestershire.
Bjay
Posts: 9
Joined: 19 Apr 2022 22:50
Location: Teignmouth

Re: Misfire under power

Post by Bjay »

dunk 1 wrote: 10 May 2022 16:30 That looks like the nlm "performance!" pick up to me - I think there is information on it in somewhere in the library - if you can't find it I am sure I have a copy of the instruction set up somewhere.
Duncan
Hi Dunk, I would appreciate a copy of the set up instructions please. I've proved it problems are ignition related, so that's a start. A photo/ pdf would be great, norton690@gmail.com
dunk 1
Posts: 208
Joined: 25 Oct 2007 18:16
Location: cumbria

Re: Misfire under power

Post by dunk 1 »

e mail sent - sorry a few days late
dunk
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