Modern Vespa

Hello all,

I'm in the process of trying to rebuild my first engine and it's a bit overwhelming. I get to a point where everyone says, "this is the hard part," and I kind of freeze. I'll bite the bullet, get that step down and move on to the next "hardest part" and freeze again.

All the information on the internet and books are super helpful but I still think I'm going to fuck it up. Not to mention not knowing which parts need to be replaced, not ordering them and having to wait.

Currently I am avoiding installing the crank with bearings into the engine. I'm afraid I'm going to mess it up and things will not be straight. So now the engine is just sitting there, taunting me.

My question to all of you, how was your first rebuild?

Mine was similar to yours, only without the wealth of information that's available today.

Try doing it with no YouTube videos or discussion forums, plus the state of the art on working on vintage motors has improved tremendously in every aspect: information, parts quality & variety, techniques, and standards of quality.

For example, five years ago, I'd guess less than 10% of the builders in NSM pressure tested their motors after building them. Now, I'd say it's probably closer to 90% because people understand how to do it, how to build a cheap test rig, and why it matters (you'll struggle to tune the carb, and eventually seize it if you don't)

Looking back, all I had was the Hayne's Manual, which is only useful to someone who already knows how to do everything and just needs a few pointers on the sequencing, and crappy kits like the DR, which getting to a sustainable state is an art unto itself.

First thing to do is get yourself a build thread going. Document progress and questions with your posts. If you have questions, add it to the thread, ideally with some pictures of what you're referring to. It also gives you a reference volume for when you forget your thinking or decisions down the road.

The NSM Hive Mind will then descend and, other than some differing opinions on the "best" way to complete the task and some good-natured teasing, advise you on what you need to know incredibly quickly.

I refer back to my old build threads all the time, for both my own and others' benefit. I dredged up information on large vs. small cone cranks from a 2018-19 thread to answer someone's question just a couple weeks ago.

The only real crime around here is ignoring good advice or bad news because it's not what you were wanting to hear. So long as you're listening, learning, and sharing, this crew's willingness to help is limitless.

My first build was before high speed internet, so it involved alot of long distance phone calls to San Diego, and to Phoenix to get some guidance. The best advice I received was " to remember these are pretty basic engines, that are massed produced, and anything short of forcing it together with a sledgehammer can be fixed".
Once I took that to heart, I jumped in and made mistakes, learned from them, and built confidence.
But there is a learning curve, and parts of "tuning " still seem mystical to me.
Hang in there, ask questions, make mistakes, and I'm sure someone on here has already made the same ones and will commiserate with you

The community here has been priceless in my journey to acquire knowledge. Just posted a problem I'm having looking for an answer. Taking things one step at a time and focusing on that one step should help with being overwhelmed. It doesn't have to all be done right this second. Be easy on yourself.

The heat and freeze method of bearing installation is a time proven method especially if lacking specialized tools.
Post some photos.

Bunch of good how to videos at Mercato and SIP:

https://www.scootermercato.com/Garage/Tech-Tips/Engine-Assembly-Part-1-Large-Frame

I fully agree with previous comments. I'm currently doing my first rebuild,still waiting on new crankshaft. The help from members has been fantastic. Slow and steady is my recommendation. The SIP tutorial series via youtube was awesome, it helped me put names to components and sequences to follow. Made me realise they are quite a basic engine but need some finesse in certain areas.
Good luck and once it's completed I think you will give yourself a pat on the back instead of an uppercut.

You're already doing it right.

You're going to make mistakes. It's part of the learning process.
If you start to get frustrated, stop what you're doing and come back later.
Watch the videos. Ask questions.
Handle the parts and dry rehearse the steps to make sure you have the tools and have the sequence in mind. Take your time.
Take it one step at a time, and eventually you'll run out of steps and it'll be done.
We've all been there.
Good luck.

Like everyone else said. You'll make mistakes. So long as you learn from them then you're doing fine.
Just remember to install the kickstart gear before you button it up!

But yes I had the same anxiety worry I'd break something. Went smoother than I expected. This winter or next I'm gonna rebuild one of my bikes engines and put a short 4th gear in while it's open.

Don't sweat it. Like someone else said, these are simple, well-designed engines with surprisingly few moving parts. Everything fits together pretty easily. My general advice would be make sure you have a good set of tools and don't get frustrated and try to force something. If you get stuck, MV is an amazing community and there are a lot of people here willing to help.

My method involves reading about it, watching videos about it for months. At some point the constant exposure to the ideas the familiarity with parts and their function starts to fall into place. By the time I actually get around to doing it I recall that so-and-so said make sure to heat this bit and freeze this bit, so I do that. Takes a lot of the stress out of it for me.

The hardest bit I find is getting to a section that I'm sure wasn't shown or discussed and (being in a hurry by that time) I'll wing it. That's when I have issues generally.
So my advice - don't set yourself a deadline. We're pretty quick to answer most problems here and there's very few things we haven't seen or at least heard about.

I had ridden scooters for years before rebuilding a motor. I did two at the same time. One stock, one completely not stock. I watched the scooterwest videos 100x. Smallbore corps has well filmed ones. The sip videos. There are so many videos that are so detailed, it's pretty easy to feel confident. Before my first motor build(s) I had no real prior motor experience. Just top end and clutch replacements. Go slow, get all the tools and parts. And try to do it in one sitting if possible. Waiting weeks or months in between each step is where memory starts to interfere.

Also take pictures as you disassemble the motor. Then when you rebuild and you have no idea what that bolt could be for, you'll have a record of where it goes.

Doing the teardown and rebuild in quick succession also helps with this tremendously. Especially if you can lay the parts out as groupings, e.g. "all the clutch bits here..." even though there really aren't that many parts.

I also like to reinstall the smaller bolts/screws and washers a few turns in some cases so I don't lose them while things are apart, like stator plate screws. Removes any potential for loss or confusion.

I like the cardboard method for bolts, very roughly draw the outline of the part on it, stab holes in the right places and put the bolts through them.

MJRally gave me this gift years ago for keeping little bits organized

Clever

my first rebuild was a Super in '89. Stacy from First Kick walked me through it over many phone calls. i'll never forget the number of times she started with " 'k sweetie, next you're gonna....."

VBB?
If so, get this tool if you don't have it already. Make sure the arm of the crank is free from bumping against the case as you pull it:
https://www.scootermercato.com/Scooter-Parts/Factory-Tools/10052700

Closing the cases no-heat at 29:30 here, with the tool:

Thanks for all the encouraging words and helpful recommendations!

I ended up getting the cases back together. Hopefully everything is right in there!

I got finished rebuilding the clutch and got that installed. When I was torquing one of the bolts it snapped. Luckily enough was still out that I was able to remove it without much fuss.

Just really nervous about breaking something.

Glad to hear you're making progress.

Which bolt did you snap? A clutch cover bolt? Those things are barely more than finger tight.

Are you using a torque wrench?

^^^^ Clutch cover bolts - 4.5 to 6 lb-ft. Barely more than the weight of the wrench itself hanging on the bolt.

Yeah, I messed up. Was working late and kept pushing (even though I should have stopped). I set my torque wrench too high (another stupid mistake). Luckily enough of the bolt was sticking out that I could get it out with my fingers.

I also went out and bought an inch/pound torque wrench. Hopefully easier to get the smaller adjustments.

Yep, another late night mistake🤦‍♂️

We've all done something similar. At least you didn't strip the case hole. Then you'd get to decide if you wanted to go with an M7 tap or a helicoil.

Totally normal for me at least. Something gives me problems every build. The core of rebuilding old engines is learning how to fix stuff that strips, breaks or gets damaged when fitting. Eventually you get better at that part and it's less stressful, though still a pain in the ass. Be forgiving of yourself even if you do something dumb. This is the path we all take.

The best tip I've had as a novice wea to stop when you are winning: when everything goes fine. You'll have a nice feeling and won't be tired.

If you keep pushing it, eventually you'll get frustrated and things will stop fitting.

Take your time. There is no rush.

This is the theme of my ET3 build... to a sad, murderously slow extreme.

Slow is smooth, smooth is fast.

I found that out the other night. Kept pushing cause I wanted to finish the clutch. Luckily it was a simple mistake.

Taking my time is the hard part. Feel like I just need to get this done. I don't even know if it's right or will start when I get it all done haha.

Right? I just want to get this shit done. I want to ride my first largeframe (besides a P).

One piece of advice I gave on another thread: if you have the means, own at least two bikes, so you have something to ride while you're wrenching. Well, not literally at the same time - you know what I mean!

That way, you won't feel the same pressure to rush and maybe cut corners to get your only bike running.

That's some good advice! I have a Stella and a couple smallframes that I can ride. But…… I keep buying more scooters so my project list keeps getting bigger and bigger🤦‍♂️

Hopefully you will naturally FREEZE again & all will be ok