New owner, strada

[tobydmv]

Greetings, new owner here looking for some help and parts hopefully. The motor was completely seized but is now free. I plan on getting the motor out of the frame and splitting the cases for a good cleaning and bearing replacement. I'm putting together a shopping list of parts that i'll need. The stock pistons were damaged in freeing the motor. The compression rings are seized in their grooves. I'll need a set of pistons, most likely 2nd oversize(.4). Both the exhaust and intake valves are pitted and pretty rough. They will need replacement as well. Will need a cam belt, gasket kit, and seals. Looks like Stuart at NLM has everything I need. Here's a few pictures

[mgelder]

Welcome aboard!

Thought I saw a glimpse of whitewall tyre there for a moment, but no

[tobydmv]

Guys, I am going to split the cases. Is it ok to split them from the magneto side? That should leave the transmission and the crank still in the kick start side. Any tips on splitting them? I usually tap with a rubber mallet and lots of heat.

[EVguru]

Here's a tip, read the manual!

It's a very simple engine to work on, but there are some unusual features and little 'gotchas' you need to know about.

You should take the opportunity to upgrade the timing side bearing to a roller on an early engine like yours.

[tobydmv]

Here's a tip, read the manual!

It's a very simple engine to work on, but there are some unusual features and little 'gotchas' you need to know about.

You should take the opportunity to upgrade the timing side bearing to a roller on an early engine like yours.

I have downloaded and printed the manual. Thats always good advice. I was looking for a little practical info from you regulars who have been working on these for awhile. What are the gotcha's to look out for?

I did a search on the roller bearing conversion and it looks like it requires the crank to be turned down, is that correct? I have most of the motor stripped and i'm seeing a few things that will need attention.

Mainly in the heads, the CC surface and valves are pitted pretty badly. Ive seen this on my motobi before. Any idea what might cause this? Both cylinders and all 4 valves show damage. Would milling off a thou or two to get rid of the pitting change the CR?

[EVguru]

I was looking for a little practical info from you regulars who have been working on these for awhile. What are the gotcha's to look out for?

Generally simple stuff like knocking the hollow dowels through, not missing any bolts and keeping track of the gearbox shims.

The engines are generally very reliable and long lived, so rebuilds aren't that common!

I did a search on the roller bearing conversion and it looks like it requires the crank to be turned down, is that correct?

Early engines used a deep groove ball race on both sides of the crank. The one on the timing side was meant to be a sliding fit on a hardened sleeve pressed onto the crank to accommodate expansion. They didn't always get the tolerances right and you'd get premature crank wear, or the bearing would move in the cases. The later engines had a plain bearing on the timing side and this has to be ground down to take the roller. It's really only worth doing on a plain bearing engine if the crank needs grinding anyway, or you're doing extensive tuning. The changeover date was around 1976, so a drum braked Strada would probably have the earlier engine (although I know of a 1978 built drum braked Strada).

I have most of the motor stripped and i'm seeing a few things that will need attention.

Mainly in the heads, the CC surface and valves are pitted pretty badly. Ive seen this on my motobi before. Any idea what might cause this? Both cylinders and all 4 valves show damage.

Might it perhaps be related to why the engine was siezed?

Would milling off a thou or two to get rid of the pitting change the CR?

I don't think you've quite grasped the Heron head design. You're not changing the combustion chamber volume by machining the head, it's flat!

I'd go with the higher compression Sport pistons, later 350's were all 11:1 with a cam sort of half way between GT/Strada and Sport. I prefer the Sport setup, the engine has more torque all the way through the rev range.

[tobydmv]

Ok the cases are split and noticed a few things that dont look right.

1. The rod bolts are different lengths. The clutch side rod has shorter connector bolts than the mag side rod, reason for alarm....?
2. Bearings look worn, guess the crank needs to be inspected
3. Pulled the clutch side crank journal plug out and thought there was metal behind it. The passage was completely blocked. Its clean down to the crank now.

[George 350]

Hi Toby,

The big end lower shells don't look badly scored, but what are the upper bearings like? If they don't look scored either, then the only way to see if they are worn beyond service limit is to measure them. The crank gallery being blocked is a sign of insufficient oil changes in its past, as the 'oil filter' is really only a strainer. (The centrifugal force of the crank spinning will throw any metal particles and other 'debris' to the outside of the hole along the big end journal.) If it were mine, for the relatively small cost involved, I would replace all the shells as a matter of course. The only question being whether a regrind is necessary or not.

Regarding the big end bolts being different, I think early motors had small bolts, and were upgraded to rods with bigger bolts. If you have one rod with small and one with big, then it is probable that something has gone wrong in the past. If it were mine, I'd replace the small bolt rod with a later one. Morini didn't modify many parts on the bikes without good reason, and breaking big end bolts was one of them. Whether the rods can be machined to accept the bigger bolts I know not as both mine have the later rods. Paul or NLM should be able to advise you on that.

Regarding the heads, if pitting is evident on the flame face, then skimming might clean it up, then again it might simply uncover more porosity in the casting. In the car industry, a process known as 'smear milling' has been used to cover it - involves milling with a slightly blunt cutter that 'smears the metal being cut into the holes! Unless it is really bad and is porous to the outside, then it is probably ok. Valves and seats can be recut and lapped to recover them.

Other jobs you should budget for include a flywheel re-magnetisation and ignition coil re-winding, bearing in mind the age of your bike, and possibly the need to make or buy a new ignition amplifier kit.

Set yourself a budget limit. NLM has Stradas for sale at £5-5500, guaranteed running ok and with a warranty. You see them go for quite a lot less than that privately, although that is without a guarantee of course. Add up the cost of all you need to do and would want to do and consider whether you would be better off breaking it. I do hope that you would want to see it running properly though - I am in the final throes of resurrecting a '78 Strada (I bought it to use as a spare parts donor but decided to restore it) and that has cost me around the £3000 mark to do, and I am lucky enough to have all my machining done for free and did all the bead blasting, made the wiring loom and ignition system, did much of the minor painting and all mechanical work myself.
I contracted out the chroming (£200), powder coating (£160), zinc plating (£40) and tank / sidepanel spraying (£200).The rest of the money was spent on new parts for it!
If you do decide to rebuild, then enjoy the rebuild and life as a Morini owner.

George.

[tobydmv]

Thanks for the info George. I love doing the work myself. Makes me happy to get one back on the road.

Small end bushes look fine. I will measure them to be safe. The gudgeon pin tapped out very easily.

Stator ignition coil measured 210 ohms. Doesnt look like I can pull it off the plate to clean the ground.

The ignition rotor was rusted badly and the pickup unit was damaged. One of the cover screws seized.

The con rods are numbered. I'll try to post a picture of them tonight. I remember the numbers being quite different so maybe one was replaced. This is an early strada, double drum brakes, black tranducer coils, red pickup unit, still have no idea what year. If I offer up the number on the frame would it help identify?

Lots and lots of work to do! I just completed a 50 mile classic rally on my motobi 250. Next year I hope to do it again on the morini.

[EVguru]

Small end bushes look fine. I will measure them to be safe. The gudgeon pin tapped out very easily.

I'm pretty sure George was asking what the upper big end shells were like, your pictures aren't explicit as to which shells are shown.

Stator ignition coil measured 210 ohms. Doesn't look like I can pull it off the plate to clean the ground.

A resistance of 220 ohm is normal as far as I'm concerned and 210 is within range.

If I offer up the number on the frame would it help identify?

http://www.motomoriniclub.nl/framenumbers.html

[tobydmv]

A/2 * 07093
DGM 11040-0M

[MarkB]

My Strada (TLS, not double drum front brake) is 07242 and that would date it from early 1975 although it wasn't registered until October 1976. The Dutch Morini club website has more details of frame numbers and dates of manufacture.

Good luck with the rest of the rebuild. Regards, Mark.

[tobydmv]

I am having a devil of a time removing the crankshaft belt pulley. It looks to have rusted onto the crank. I'll have to make a new puller to get this sucker off.

[EVguru]

A 50/50 mixture of ATF and Acetone is one of the best penetrating lubricants available.

Some heat will help and a hot air paint stripper with a narrow nozzle is often a much better choice than any kind of flame.

You need a thick washer to go behind the circlip on the pulley and you can recess the back to allow it to be thicker. It should be a really good fit on the pulley so it only just slides on. The last really stubborn one I removed needed the aplication of the air gun to the end of my three leg puller.

[tobydmv]

Not sure what happened here but it looks like mismatched rods. Kind of hard to tell by looking but the red rod bolts dont pass through and it looks like the rod bolt holes were drilled offcenter.