Modern Vespa

Have fun refitting the engine to the frame...

After fitting my Polini 294 kit, it must have taken three of us over 30 minutes to get all the bits and brackets aligned to slide the bolt through. Damn but that engine/drive/wheel combo is heavy!

Eventually we used a wooden dowel stick that was slightly smaller than the bolt to align and support the bits and pushed it through with the bolt.

A real PITA!

This is common occurrence. Those bolts are one time use, made to stretch. However like many of us, we reuse them, until one day your set the torque just a little to high, and snap. Head and barrel have to come off depending on where is snapped at.

they studs are cheap and readily available. you may need to order the special O-rings if you have already placed them into the tunnels. Take your time. Harbor Freight has a small torq wrench for cheap, which will go low enough for the low torque numbers needed here.

Good luck this is just a small set back.

We did something similar. Robot makes it look so easy. I found using shims between the Scissor jack and the frame of the bike made the aligning of this much easier.

You tube makes everything look easy.

It was heck of a job to take the cylinder base off (the black part of the engine). The studs had some grime on it that it took me about 2 hours to take off. one millimeter at a time. In the process I moved the piston thinking that it was the piston that was stopping me from getting the cylinder base off. Did I screw up my start or can i move the piston all the way up when I assemble it and it will be still ok to start?

You're going to want to turn the crank until the piston is at top dead center. Make sure you do NOT let the timing chain get all wadded up at the pulley on the crank.

Beyond that you probably should watch a video, so you understand how to reinstall the piston into the cylinder without breaking a piston ring. Also, you want to set the ring gaps about 120 degrees apart. Do you have a copy of the shop manual?

I don't but I see Robot from scooterwest has a three video series on disassembling and reassembling the complete engine. I have been following it closely for the most part, except that I get many curveballs with my older weathered down engine.

how much does one torque the studs going into the engine block?

link to the workshop manual, this should mention torques https://www.vespaforum.com/manuals/Vespa/GTS300-2015-ABS/GTS300-2015-ABS.pdf

You should download the service manual. I don't have it handy or I'd look it up and see if there is a spec. If there isn't a spec, I'd use a bit of blue locktite and turn until they bottom/get snug.

Torqueing the studs down is not needed. As long as they are in there fully, use 2 Bolts to tighten it down until it is snug. These Studs are designed to stretch, therefore they will stay tightened after fully torqued.

You will want to take the belt cover off of and use a wrench to turn the fly wheel until you get back to TDC. Once you have gotten everything back together, give it a couple full twists and make sure TDC is lined up with the Cam pulley 4V mark.

Another tip, when you attempt to reattach the piston to the rod, keep a towel covering the Hole into the crank shaft, so the clip does not fall down into the bottom of the motor.

Super tips. It's contributers like you that make MV such a great place.

You also asked if blue loctite is hi temp - short answer, no. But it is all that is needed in this case.

nope

Agreed, but they do leave us with a little wiggle room when Piaggio/Malossi state 90 degrees torque. Unless you have a high end torque wrench, this is a best guess.

Personally I have snapped enough bolts in my life, I prefer the under as opposed to over when presented with these metrics. I wonder what the other garage mechanics do in these circumstances. It really is a judgement call, and a dilemma we all face.

Best guess big time! I couldn't agree more. It is all about the feel. For me knowing that it is about the stretch, and that once the nut starts feeling like it is dragging as its getting tight it is time to stop. Definitely a "feel " to it, and learning curve to develop feel.

the studs finally came in and I screwed them on. In regards to the cylinder, does it need to be removed from the crank? or can i just reinstall it as is into the cylinder head?

I must admit I am a bit confused by your last post. I don't see a cylinder in the pic, just the case with one stud installed.

The piston does not need to be removed from the crank, no.

But it does need to be extended to top dead center (give or take) to allow room to get the piston rings into the cylinder.

Aah, the light is coming thru, thanks MS.

#1: Keep at TDC all of the time. Period. Don't move it once there. Period. Keep checking it all the way to the end of your build because you will need it at TDC when you put on the chain.

#2: You can put the piston in the cylinder when the piston is on the bike, but for me that was much harder. I took off one of the piston retainers, took off the piston, made sure rings were at correct angles, and installed into piston. One at a time, squeeze the piston rings and get them in the cylinder (and imagine yourself trying to do it while the piston is still attached to the crankshaft). When the last ring is in, you will have just barely enough working room to reattach to crankshaft and reinsert retainer pin. That last piston ring will be right at the edge of of the cylinder ready to pop out if you are not careful. Do it just like the scooter west video. You might accidentally let the last ring out and have to start over once or twice, but it is still easier than trying to do it with the piston installed on the crankshaft.

#3: All the while you are working, KEEP EVERYTHING CLEAN. EVERYTHING! Wash your hands, Use gloves, change often, don't touch anything with greasy fingers, have some alcohol or your other favorite quick-evaporate solvent to keep the base gasket surfaces clean all the time. If that chain is oily, get it clean and dry before you begin so that it doesn't get oil all over everything.

I personally would not remove the piston, but I can see how that would simplify the process in some ways (and complicate in other ways).

Anyways, if you go this route, do not reuse the wrist pin clip / c-clip. And you will need to pay attention to orientation, with the open end not to remain at the installation cut out.

I got it done. It wasn't as bad. I actually, attached the engine to the body and surprisingly it was not as bad as I thought. I only forgot to put a clamp on one of the coolant hoses, that clamp is taking me forever to put on because of the tight space, longer than reassembling the engine! I am in the last part of connecting all of the wires. Will keep you updated if it turns on!

rear rotor play? Now that I am re-assembling the scooter, I noticed that when I put the brake caliper back on that the rear rotor has about a millimeter play. Is that normal. I tried searching for it on the forum but may be i didn't do the right search, but I couldn't find much.

Finally, I put it all together! I was afraid to turn the scooter on. When I did, it looked great, then it started to smoke!!!!! omgggggg. I looked where the puddlbe is coming from, I realized two spots, thermostat housing, and a hose right next to the thermostat. I fixed the clamp around thermostat and tied the screws on thermostat and the leak stopped. I rode it for about 400 yards, weighted until the temp was normal. Everything seems to work fine. I am soooo nervous!

Awesome

Zip ties are important to make sure hoses and wires don't rub and wear out prematurely.

Good job! Just the mere fact that it started means you got it mostly right. Time will tell!

Its been about 400 miles since I did mine. I am still checking my oil for any signs of internal leakage and all looks good.

Congrats.. As Berto mentions above, Zip ties are very important. there is a lot of heat and a lot of vibration going on under there. Make sure you place the zip ties back in their spots.

Also make sure all the hoses are clamped down, this is an important step as well. All those little plastic snap clamps server a purpose of keeping the hoses away from the heat. Lastly, the Spark Plug wire, ensure it is snug to the clip attached to the chassis. Other than that, you may have to Adjust your valves at some point, so remember the steps you did in dropping the motor.

Happy riding. Keep 2 wheels down.

nope

thank you all for your support. I wouldn't have the courage to wrap up the project without you all.

thank you! I have adjusted the valves during this process. I hope that I don't have to adjust them for a while after that!

It's a common fact that there's a huge black hole inside all Vespas where lost tinnerman clips fall into, never to be seen again.

any thoughts on this?

This is without the wheel on I take it? The rear axle will have a small amount of play all around before it's held firmly in place with the wheel on and the bearing in the exhaust support bracket (aka "swingarm").

thanks!!

it started to leak again I am not sure what to do here. Should I just go to a dealership and trade in my old vespa for a new one or try to get a new cylinder head and valve head?

Double-check where the oil is coming from - it might not be the head again. If it is, if you can afford the time and effort the cost of a new gasket set is SO much cheaper than what you'll lose in trading in for a new one.

However, be aware of the sunk cost fallacy (or escalation of commitment).


Personally, I'd swear at it, get new gaskets and now that I know what I'm doing, keep it spotlessly clean and torque up the new gaskets absolutely bang-on to the spec.

Maybe you should trade it in for a Honda or a Yamaha (or maybe a Kymco or a BMW??). I'm going to replace my head gasket and base gasket soon, and I'm dreading having the same experience as you. I'm hopeful it will be okay, but I'm worried it won't. I love my Vespa GTS300 - it's amazing - but I need to ride, not wrench. I just don't have the time (nor the skill or desire) to fix broken Vespas, and I can't find anyone competent to do it for me.

P.S. - If anyone knows of a GOOD Vespa mechanic in my area (Connecticut), please PM me. The two nearest dealers won't touch it... I've spoken to them and they are somehow too busy to make $1000 with a gasket replacement. I have the engine out, but I really want nothing to do with this. If you are a vetted and not-over-confident "backyard" Vespa mechanic in my area, PM me. I'll pay you.

nope

If you already have the engine out you've already done the crappy part. I'm in the mountains of NC. If you were near me I'd tell you to Bring that engine to me with your gasket set and I'd replace the top end gaskets for you. It's just not that difficult. If I started on it mid morning we'd be done in time to grab lunch.

I'm on my third strike with a head gasket on our 2005 Subaru Outback - finally found that one head bolt was slowly stripping its way out. Torqued up fine the first two times (many 1000's of miles in between) but this time - meh. Never mind, I can hire the Timesert kit for only $130 - it's $550 to buy! According to every post I've seen in forums etc etc this will be a 'golden' repair, stronger than before.

So although getting the engine out (much liquid bribery to neighbours for lifting gear, engine stands etc) is a PITA, it *will* get done. There's no way we want to have to pay for another car, and as soon as the last four cats decide it's 'their time' we'll be off travelling in the van anyway!

diffuzion, having to do the head gasket again may seem like failure, but it's not. All part of life's great learning curve.