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Afternoon all!

I'm stripping my Strada engine down (including the crankcases) & I'm assuming that I must remove the cam pulley on the one side AND the self locking nut on the other side, before drifting the cam out? The NLM engine strip feature seems unclear on this matter. Can anyone help me out with the correct sequence of events to remove the cam please? I'd really appreciate any tips.

Cheers

Gary

Yes, take the belt pulley off and the locking but on the other end allows you to take the ignition rotor off then the pick up stator plate. Then when the crankcases are apart the cam can be removed. Don't forget there are two dowel tubes in the crankcase mounting lugs , fore and aft, along with one casing screw hidden away in a recess too. I've got the blue Morini manual and the Harglo books if you want to borrow them Gary?

Hi Steve & thanks for your continued assistance!

I've got the blue book but struggle to navigate it on this particular subject & the photocopy quality of the pictures is poor in general. I'd appreciate looking at your books as I've struggled with clear information & images on this particular matter. I'll drop you a text to see when's convenient to drop by.

Many thanks

Gary

I just disassembled a "donor" bottom-end to use the internal parts on a customer's 3 1/3 Sport. Neither cam drive sprocket came off willingly, rust was the culprit, both required a liberal application of penetrant and a puller to remove. The lower one was fairly easy - I machined a thick washer for behind the circlip and with a 3-legged puller it came off. I didn't have a suitable puller for the upper pulley, so bought one at the local auto parts.

Hi Charlie

Thanks for your thoughts on this. Fortunately I've been a deal luckier (so far!) & have now got the crankcases split. It's looking pretty chipper in there so far. However, at 60,000 miles, I've got to decide whether to change the big end shells & main bearings for safety's sake..or just put her back together again & trust the evidence of my own eyes (& the verniers)?

Cheers

Gary

Gary D wrote:or just put her back together again & trust the evidence of my own eyes (& the verniers)?

You never trust callipers ("guess-o-meters"), measuring crank journals is a micrometer job. Having said that, if the shells and journals look and feel good, you're probably OK. Check the clearances with some Plastigauge if you can.

I'd go along with Pauls' advice here but replace the ball/roller bearings while you're in there. They are very cheap compared to the shells and more likely to need changing. Go for good quality bearings with decent cages, it seems some recent (and ancient ) failures have more to do with collapsing cages on main bearings than you ever see with the big end shells.

The big end shells from the Fiat Multipla from the 60's/70's are the same diameter and a quarter the price of NLM ones. They are also lead-indium and slightly wider than the standard Morini shells thereby lowering the load on the bearing. Make sure whilst engine is down that you remove the grub screws from the ends of the crank pin as the crank pin cavity acts as a centrifugal purifier and the crud eventually cuts the oil supply to the big ends. I have rebuilt a number of engines for people with a failed big end bearing owing to this problem, including my own Sport 500 when I bought it. They all swore that they changed the engine oil every 2500 miles and had between 20,000 and 40,000miles on the clock.

P.S. That's why I fitted a full flow oil filter to my bikes based on an original idea from the Dutch Morini Club. Use one from a Corsa as it is unobtrusive, cheap and keeps my expensive oil clean and my cam followers in pristine condition and of course stops my plain bearings from failing.

Paul, Steve & Harry

Many thanks for your good advice. I'll get busy accordingly! Do you have any thoughts about replacing the layshaft & mainshaft thrust washers & bearings? All seem ok...but if they're not a million dollars, I'm thinking it might be better to replace them?

Cheers

Gary

To avoid problems the next time you have to open the crankcase:
drill two more holes an give them a 10mm thread, take a good piece of iron with two holes of about 10 or 10,5 and a 10mm thread in the middle. Then you´ve got a puller for the upper sprocket
ciao
norbert

That's a useful tip thanks Norbert!

I would certainly replace any ball bearings as necessary but you will have problems with the drive side main bearing as it is obsolete which is why I bought a coupe a long time ago, and also the split bearing in the gearbox. However, the drive side main bearing problem was solve bt Adrian Crimp - not sure if he is still in the club, but through job at Bristol University got SKF to modify a standard bearing which was given a separate bearing number by SKF. I have the number in my reference files, so if your split main bearing shows sign of age I will let you know what it is. All seals and bearing are available through a bearing stockist and trade prices usually 60% off. I assume you know how to read off the 6 figure sizes for the seals,, they are clearly marked. I keep a spare set in my goodies cupboard as they are so cheap. If you need to borrow the assembly sleeves then I have a set, alternative rap some electrical tape round the shafts so you don't run the risk of tearing the lips when assembling.
Regarding your request for information on 71mm pistons. I had a batch made some time ago by Omega Pistons as I had the last set of pistons from Asso in Italy and they had no intention of making anymore. The 'normal' cylinders on the 500's are different from the 507 (71mm ) barrels. Apart from having Nikasil bores the spigot part that goes into the crankcase is of a larger diameter. It is aluminium, so you if fitting it to a standard 500 have to either open out the holes in the crankcase or turn a little off the barrels. It is only about a millimetre but in my note. I did consider having standard barrels bored out to take the 71mm pistons but consider the liner to be rather on the thin side for everyday reliability. I fitted 70mm pistons to my Sport and have had no problems. If you do decide to bore your engine out then from experience stay away form pistons made by the mainland Chinese or the island Chinese and go for the Triptsch pistons. Incidentally, the pistons I had made by Omega are always squeeze forged and they used the dies from when Devimead tried to keep the overboard Morini 350 race bikes together. The pistons were fine, the achilles heal of the Morini engine kept letting them down. Again incidentally, if you are two up or touring and want a flexible torquey engine then retain the standard camshaft and if you really want more power the best cam for this engine is the 350 sport camshaft as it is does not have a massive overlap but does have better lift and so will keep your usable power band reasonably wide and not have to practise playing organ stops with your right foot.

NLM have the drive side FPAC bearings, if at a fairly high price. They used to be cheaper from the US prior to the Pound devaluing.

I think Tom got hold of some Cagiva or Ducati packaged bearings with the correct Morini part number and they turned out to be standard dimensions.

I wonder if Morini didn't get originally get hold of a job lot of modified bearings and have cranks ground to suit. Then went to standard bearings when the stock started to run down.

I bought this bearing for a customer's 3 1/2 Sport engine. Wasn't sure if it'll work or not, but it was cheap enough that if not I wasn't out much.

http://www.ebay.com/itm/Morini-250-350- ... 5405d09e99

Thoughts?