Oil leak

[Emmohaswheelsagain]

Thanks Mike/Mark for your comments. It is certainly a fact that Morini’s run best when they are used and certainly with my previous bikes I have tended to use them 12 months of the year. Obviously during the winter months this has only been when weather allowed but nonetheless this did work particularly with the 9 1/2 which was 100% reliable during 13 years of ownership.
Acknowledging that the bike had been off road for 3 years I did take the trouble of having the bike serviced/checked over by a Morini specialist, tank was drained, float bowls drained and new fuel purchased. All fluids replaced, engine & fork oil, brakes bled with new seals/fluid. Cam belt replaced, tappets adjusted, timing checked and carbs balanced, as you can imagine the invoice was not small although I did buy the bike with this cost in mind. That said like any old machine there is always more to replace, clutch cable, this was found to be hanging by a thread after riding the bike from the garage. The ride home also confirmed that the bike was running rough, inspection of the plugs confirmed the front pot running rich, the specialists suggested i look to see if the choke was stuck on. The 500’s have a cable operated choke which I found badly routed and decidedly second hand, this was replaced by a couple of flick up chokes, my previous ownership of several 3 1/2’s mean I am proficient at operating these whilst on the move. Unfortunately the rough running continued so I stripped and clean the carbs, replacing all gaskets, float pins and needles which were in poor condition. At the same time air filters were also replaced, these were in bad condition and should have been checked during the service. There were other small details which needed correcting, the new plugs were BP8ES so I changed these to 7’s which are considered to be the correct. The gasket on the filter cap had perished so I replaced this. The tips on the mixture screws were also pitted so these were replaced with new springs, washers and o rings, carb inlets were also checked for air leaks and throttle cables checked to ensure smooth operation of the throttle bodies.
As you can tell it has been a journey. I will as you suggest replace the float needle/valve. I have inspected the floats, these seem fine, they are the correct type, GR 11.3. If the problem continues I will replace them obviously but for now I will wait and see. The 20/50 option seems a good idea, I assume this will help seal the rings. Do I revert back to the 10/40 after say 500 miles? I will of course keep a close eye on the oil level to see if any contaminants (fuel) is getting into the sump. Thanks again for your help.
Regards

Paul

[Emmohaswheelsagain]

Further update, I have tested both the needle valves and the needles and no leaks to report. I had previously replaced all the o rings/gaskets/washers so I was fairly sure the needle valves would be seated ok. I have also cleaned both carbs, i don’t have sonic cleaner but both carbs look serviceable. The next job is to check the condition/adjustment of the floats. As previously mentioned they are GR 11.3 (black) as shown on Euro carbs website. They do float, no leaks so I need to check if the floats are jamming in the float bowl. In addition I need to check the float level, not sure how critical this is, the blue book quotes 10mm but this is measured to the centre of the float. Fuel taps are closing off correctly so beyond a fault with the floats I can’t see an issue within the carbs.
Any suggestions welcome.

[Ming]

The Dellorto manual (look online) shows how to check float levels.

[mbmm350s]

Hi Paul,
To be fair it sounds like as an experienced Morinist you have done or had done pretty much everything.
I wonder if the fuel leaking past the valve was just caused by disturbed crud which has now been flushed out. I mentioned checking that the fuel filters are in place, i once found a spare one in a tank just milling around, so i guess they can fall off.
One thing is I wouldn't bother with carb balance on an engine that's been stood for a while until it's been run back in a bit followed by an Italian tune up.
As Ming says the Dell'orto setting method is I think easier to grasp for the 26mm carbs, I think it's in the members area. Euro carb can sell you a paper copy it's not expensive. So many bikes have been messed about with, so it's doing as you have done and double check everything thats needed. For example even if jets have a number never assume they haven't been drilled, or needles so polished that they are a totally different size.
Another thought is that the starter jet is bent leading to a poor fit of the float bowl.
After 20/50 I would go for 10W/40 semi synthetic oil but one designed for, or meeting the requirements of, air cooled motorcycles. I use Morris lubricants Sport 4 but we also have 250s with wet clutch and some car type oils aren't suitable from our experience with wet multiplate clutches. Its more expensive than oils aimed at car market, many on here use Halfords oil, with good results.
Anyway I am sure you will sort it out.
Mark

[Emmohaswheelsagain]

Thanks Ming/Mark for your suggestions, wise words indeed.
Mark - you are right to suggest that many Morini’s have been messed with, unusually this 500, on the outside at least, looks like it has just left the showroom, probably that was my error as the V5 shows nine previous owners, so plenty of scope for set up issues.