I need your help

[Morinimatt]

Hello

I am posting in the projects as this is a project for me. My dad passed away a few months ago, i got left his 1975 3 /12 sport.

It was his dream bike but broke down every time he rode it. He had it 10 years before passing away but im not sure what maintenance he did to it.

So far i have rebuilt the carbs and i gave the fuel tank a swill out and filled with 98 ron. It fire up straight away but instantly began screaming like the throttle was stuck wide open even though its not (i have attached a video) the second time i started it it ticked over nicely for around 30 seconds before it started revving up again.

I really need some advice on how to sort it. Im pretty mechanical but carbs are something ive never worked with, i assume theres a problem with the air fuel ratio but like i said im stuck.

I also dont know the condition of the timing belt so dont want to be having to start it too much till ive checked that out. Cheers Matt


https://flic.kr/s/aHBqjACiCd

[morini_tom]

Hi Matt,

Firstly sorry for your loss.

Initial question on the carbs- are the slides in the correct way round as it’s possible to fit them backwards. Cable should enter the carb top on the engine side of the card and then rim un straight down to where it hooks into the slide, again, on the engine side do the carb.

Next, are the throttle cables hanging up? If they pull out of the carb top or twistgrip housing they can sit on top of the adjuster rather than in it. There should be some initial slack in the throttle cables.

Finally, ensure you’ve got no air leaks. Split rubber manifolds between the carb and engine, or if you still have the original metal intake manifolds then leaks from any of the joints is possible.if you can get the engine idling, spray some coldstart or similar in the vicinity of the manifolds and if you have an air leak it’ll get sucked in and you’ll get a momentary change in engine speed.

Regarding the belt, yes definitely change it. It’s easy to do and cheap enough.

Check out Paul Compton’s videos on YouTube (search Paul compton Morini)- you’ll find a lot of useful how to videos which he’s done over the years.

Morinis are very reliable and rewarding when sorted. There’s a wealth of knowledge in the club to help with that. Whereabouts are you based? We’ve got members and sections dotted all over.

Tom

[norbert]

To me that sounds a lot like air leaks concerning the rubber manifold head-carburator. Test it like Tom says with breake cleaner spray or something like this. When it is running at high revs at idle try to press the carbs towards the head or just moving their position a bit. When revs are changing, doing this > air leaks.

[Morinimatt]

Thank you for your replies i will definitely look into those bits. Could it also have anything to do with the setup of the carbs? As im struggling to find a source of info to get them ideally set up.

[Daddy Dom]

Here be carb settings.
https://www.motomoriniclub.nl/carb.html