Modern Vespa

while I'm waiting for the welding specialist to have some time for me, I went further on some parts.

The rust made its work under the fuel tank paint



Epoxy primer, then bondo (NO BONDO ON EXPOSED METAL !, common mistake in body shops), then sanding



another coat of epoxy primer



It still needs to be lightly sanded before a thick coat of surfacer, then final sand before paint and clear. I try avoiding sanding before 1 week, this gives time to cure properly. After using surfacer, the elements will be UV cured to speed up the process.

Same process on the mudguard









I can't find the picture of the final result... Will show later

Brake pedal is in poor condition, dirt, grime, oxydation... Orange and black paint overspray ! Nice









After sanding and polishing, not perfect but that is what I wanted as the finish look won't be mirror finished but brushed. I will brush the surface later and show the process if you are interested in.



For now it already looks way better





I bought a central spare wheel holder, gave a coat of primer to check the surface condition





The finish is terrible ! How can you sell brand new repro parts like that ?!
Not acceptable in this condition for the rebuilt, I spend a lot of time working the surface





The flywheel cover is still in Ok shape but has a ding





Now it looks good after some hammer/dolly time



The engine is dirty as hell ! God knows how many years of oil and dust have accumulated onto the surface, most of it is rock solid, it takes a lot of time, a lot of swear, some diesel fuel, various brushes...









Is the seal broken ?



Now the engine is in better outside shape, (still very far from my OCD standarts but that will come later), and on the stand, ready to be taken apart.



I still have to clean the carb box



The flywheel is in bad shape, some stupids probably used something as a lever and bent the flywheel on 5 or 6 points along the perimeter... I want to re-use this one because it works first, and it is original.



I was thinking of heating the aluminium with a torch and hammer dolly, is it a good method ? Is it physically possible to bring it back to its original shape ? I would be super easy with steel, but aluminium ?

I was thinking of heating the aluminium with a torch and hammer dolly, is it a good method ? Is it physically possible to bring it back to its original shape ? I would be super easy with steel, but aluminium ?
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That's an incredible amount of goo on the engine!

Be very careful with the fan. The metal is funky and tends to crack easy when worked. It's very difficult to weld and has lots of porosity. Had to repair mine. I've never seen a pink glow while tig welding before.

I think I got 3 or 4 kg of goo at the end !!

I'll give a try with heat on the flywheel, hoping for no crack

I took care of the flywheel.

The set up
using a piece of thick aluminium waste as support



I hit a wood block with the hammer a few times after heating the aluminium with a torch, then heat again, then hit... going from this



To this



There was 5 spots like that, everything went ok.

Some of the blades are in bad shape



I used the file to correct this



Next will be a coat of thick primer and paint. I'll use original Max Meyer paint code (from PPG) to finally paint and clear the flyweel.

Nice fix!

Well done saving the fan!

Previous owner drilled a hole for the exhaust bolt, why ? No clue...

From the picture, could you tell me which one is the right one and which one I have to fill ?

I'm pretty sure the original broken bolt is in the middle of the two holes…

Oh… that is the worth that could have happened… it is not going to be an easy fix ! Is the hole supposed to go completely through the swing arm or is it a closed hole ?

i have repaired a lot of broken exhaust bolts

The remaining bolt is the original. the holes to there left and right of the bolt need to be filled in. The right way to do the job is to grind out the material, TIG weld up the case, mill the surface, then drill and tap.

Mmhh... That requires equipment I don't have but we'll see.

1step is going to extract the old bolt without messing more that it is.

Maybe I can fill the holes with something like JB weld steel reinforced resin, then drill a step higher than the previous hole (at the exact same place) and use a thead insert.

As the diameter of he hole will be bigger, top and bottom of the insert will be in contact with original aluminium and not JB weld.

If it fails then I'll bring the case to a welding specialist to fill the holes with aluminium weld.

I would prefer this solution, but here in Brussels it is not easy to find that kind of welding pro + it is quite expensive !

I understand and appreciate the line of thought to try to just get something done with your best ability. Sometimes this can lead to creative solutions. In this case, your best bet would be have this hole repaired by TIG welding. You can drill and tap it yourself. It would be worth the effort to do it properly. You wouldn't want your exhaust fallin off on the road, and then have to do this job all over again. Do it right or do it twice. or thrice!

I'm currently looking for a welding pro. There is one not far from my place, I'm going to contact him.

It won't be easy to fill as the dummy has drilled completely through the other side of the swing arm…

Some people ..... ugh!

I haven't opened the engine yet, what surprises will I find ?

More seriously I hope none, the engine was running fine and seeing the amount of goo, this engine may have never been opened, the seals are more than dead… Which is a good sign for me !

I may have a 3rd "creative" solution.
I am not a welder but I'm sure the holes are too deep to be filled.
I may purchase some aluminium rod, redrill the holes the closest to the rod diameter, insert the rod, leaving like 5mm gap in length on both sides and then ask the welder to plug weld the holes. then I will drill the center hole a step bigger and use the thread insert.


Sounds ok to you ?

I like the idea of the threaded insert. Will hold up stronger than tapped aluminum, if done properly. For the welding, I would grind away the material underneath the 2 holes, opening them up to make channel, like a trough; that can then be filled in with weld. It will be a fair amount of cutting & welding, but it will be a strong repair, with minimal voids; as long as the welder gets good penetration and the cases aree as clean as they can be. Clean well with degreaser & acetone, and I'd hit it with a propane torch to cook away any oil in the pores.

That is also a good idea !

I'll ask the welder his opinion about the best way to repair

It's not the threading that goes bad, it's the constant exposure to water kicked up by the wheel. The best approach is to use anti-seize on this bolt.

I will, and make sure I use an stainless steel insert, avoiding future rust

You don't have to do that at all. Just have it TIG welded up, that job will not be difficult. What takes the most amount of time is setting the case up on a mill. I recommend finding someone near you are at least in your country that is competent with this repair. Do it right the first time and you will love the outcome forever.

That is a very good point!

After a nice fight, the bolt is out !

How did you do it?

I drilled from the center, going from the smallest size and up till I could remove the remaining parts.

I'm struggling splitting the engine case...

I did use a heat gun around the oil seal on the flywheel side, avoiding the seal itself, only around not to melt it behind the metal plate.
Then i tried to wiggle half the case holding the kick lever but nothing moves.
I tried several times...
I made sure I did not forget a bold, I removed all nuts and bolts (12 different places). I took off the clutch on the other side also.
Only remaining thing is the reverse thread caste nut around the driveshaft cause I don't have to tool here (it is at my other shop) but should not be a problem for a case splitting

I borrowed a tool from a friend but I'm afraid to use it.

I just screwed it in place, is it the right way ? I could not fix it to the highest point of the case because the legs are a bit too short.

Seeing the state of the bolts going through the case, there is some oxidation, I'm afraid that the guiding pin in between both half might be corroded and hold the cases together strong.

Would you use the tool ?

I have used the crank to split the cases. Use a center punch and give it some whacks on the crank on the clutch side. That will drive the crank out of the clutch side case and separate the fly side case off. Then repeat on the fly side to get crank out of fly side case.

Yes but no ! That is the best way to destroy/unbalance the crank... I want to reuse after checking if it is still in good shape

I've used that tool several times in the past. It's sold here branded as "Tusk". While I prefer the tool that is a flat, triangular plate with a pipe that fits over the crank, this could work if you seat all the fasteners fully and only allow a parallel alignment of the arms and the case fittings.

Don't reef on it, just load it slightly. Warm the cases with a torch where the studs and locating pins are. Tap the mating surfaces with a shot mallet. Maybe gently tap the tools bolt with an engineer's hammer. Use a wrench to look for a release of tension on the tool bolt. Heat, time, gentle pressure and careful percussion can go a long way here.

Thanks for your answer.
This is the way I was going to proceed, bit of tension, heat, rubber mallet and so on.
What worried me is the tool itself.
The 3 legs are perfectly parallel and have a flat contact to the case, I cleaned the threads into the case and used long bolts to go through in order to have maximum thread in contact to avoid ripping. One of the threaded hole is blind, I cleaned the thread also and measure the depth for the bolt to have maximum thread contact without touching the bottom.

Wish me luck

It did not go well…
I slowly heat around the bearing, put a bit of pressure, gentle taps with a plastic hammer, again and again until the case splits at the top, it I had to put quite a lot of pressure before I could see a split



Nothing moves at the bottom of the engine… with more pressure from the tool and heat and taps, the top separates a bit more but not the bottom, at all…

When I remove the bolts, one refused to to go through the case, the one in red, but I thought ok, as long as the nut is off, the case will slide through



I think there is the problem. I even used the dremel to mark the stud to able to use as a grip to hammer it with a chisel to make the stud turn or even move a bit, I whacked it from the other side but no success, it is stuck.




Now the engine is a bit split a the top, of course the crankshaft is not free as before (I took the tension off from the tool).

I don't know what to do next ! Hope I did not bent the case, that is not too bad if the crank is dead but hope not the engine case

What should I do now ? I don't have a air hammer to push the bolt through

Bummer...

I think that's the long bolt that goes through the case and can get quite crudded up and stuck.

I'd tap, tap, tap, with a punch and hammer, and with heat, until you get some movement on it.

Have a torch to heat the case a bit? I just split a stubborn, rusted case apart and that same bolt is stuck in place on mine too. Case still will separate.

I taped it with a lot of brute force and some heat, no result…

I closed the engine back, slowly using heat also, the crankshaft is not free anymore, I guess the bearings moved a bit or the shaft is bent….

You had more luck than me !

I'm a bit lost now… I may have put too much tension on the tool, the cases should have split with way less tension, I'm afraid to break the case with more tension… I guess I have to purchase an air hammer to push the bolt through the case

Spray some penetrating oil on the bolt and keep on trying. Maybe let it sit for a bit in the oil then heat and try again.

Finally !


After a lot of heat cycles, diesel, WD40, phosporic acid, hammering (I tried almost everything), the culprit is presented to you



The crank is shot ! Side marking is deeeeep, the rod has a (very) free play (very) out of tolerances



The inside is quite clean for a 60 years old engine





Could this oil seal be original ? Never heard of that brand before



The crank bearings are closed on one side (towards the internal) and open on the other, could that also be original ? Maybe this engine could have never been serviced ?!



Brand new kick rubbers



Few lines on the pad Not the worth but not the best, what do yo recommand to do ?



Next I need to remove the tube with the engine bushings, I've seen the scooterwest method using a threaded rod, gave a try with an M8 rod, the tube is out 1 inch but the threads gave up... Will try with an M10 rod to finish the job.

I'll order the extractor for the bearing behind the selector box, don't want to damage anything trying to puch it out from the external side

It has been a while !

Now the engine is clean



I replaced all bearings, next will be seals then close the engine. I rebuilt the clutch, the primary, the selector box, cleaned the cylinder and the head, I have a new piston as the original one was damaged, also a new crank will be fitted. I try to clean/refurbish/re use as much as og parts as I want to do an historic rebuilt on this Vespa. I'd love to fit a 306cc BFA engine but no, my wife would claim for divorce, as my wallet
.
The leg shield/floor has been welded, I'll take pictures when it will be back from my other shop.

Concerning the holes previously drilled for the exhaust into the swing arm, I went to a welding shop :
1. the delay is very long, they have a ton of work planned, i would have to wait quite a long time... (mid december), we did not talk about cost but I believe high as there is a big cavity to fill.

2. I did bring the half to the guy, he said I could do a solid repair without weld. He advised me to put an insert as the drilling for the insert is a bit bigger than the hole and the insert will bite for at least half of the surface into fresh aluminium, fill the entire cavity with re-inforced epoxy, then drill, tap, put the insert.

He said it would not work if it was only epoxy, or with a low torque, but as the insert is half into aluminium/epoxy (JB weld), it will be strong enough for a good a sufficient amount of torque.

I took my chance on that, here is the result.



Thread was also in bad shape into that hole, I had to put an insert

Looks pretty good. Keep us posted on how the repair holds up.

Chassis is back from the welding.

It is raw, I have to grind the welds and start bodywork

Not much done, I need to drill the holes into the floor for the runners before starting bodywork.

Not easy as I have no reference point as the new floor has no hole and the replaced parts had holes bondoed and there was no runners.