Rebuild a Vespa P125 Motor Part 2: Engine Overhaul & Reassembly

*SEE TABLE OF CONTENTS BELOW*
As this is a long and intense video, feel free to skip ahead to a specific section of the video. Also be aware there is a PART 1 of this process.
Steve walks us through the process of rebuilding a P125 motor. This will be the same or very similar on most vintage large frame Vespas with some minor exceptions. In addition to inspecting all aspects of the motor during tear down, Steve points out all the wear items that should usually be replaced during a rebuild. We also went ahead and installed a Malossi cylinder kit and upgear kit while we were at it.
TABLE OF CONTENTS:
Inspect Crankshaft - 00:36
Malossi Kit Overview - 6:06
Chamfer Ports - 9:09
Case Matching - 10:30
Malossi Overdrive Kit - 19:06
Clutch Rebuild - 27:26
Gear Inspection/Installation - 37:53
Shifting Cross - 44:05
Cylinder Studs - 48:10
Bearings/Main Seal - 49:51
Crankshaft Installation - 52:57
Cush Drive/Lay Shaft - 55:52
Axle Installation - 58:47
Fly-Side Case Half Components - 1:00:06
Sealing Case Halves - 1:01:44
Clutch Installation - 1:04:56
Piston/Cylinder Installation - 1:08:10
VESPA MOTORSPORT
3955 Pacific Hwy.
San Diego, CA 92110
For the largest selection of parts and accessories in North America, please visit our website:
WWW.SCOOTERWEST.COM
Thanks for viewing!

[@sticksen]

Now that I watched 2 and a half hours rebuilding this machine, I feel a bit like I did it myself. We wanna see this thing fire up for the first time and watch it roll! :)

[@thechimpyone]

A big thank you from England, I watched both vids and as a result was able to strip my engine replace the output shaft and rebuild it. But part 3 would be handy, reinstalling gear selector, stator plate and such. Still cheers Buddy

[@bpetnoi1472]

Really nice to see experienced and knowledgeable people who care how things are done. When you see a Vespa or any other motorcycle engine being rebuilt by many other people who lack working experience they make all the mistakes which were well pointed out in this video AND many more usually dealing with steel hammers and bearings. Yes just about any engine will run for a time after such assembly abuse, but usually not well for long.

[@VespaMotorsport]

The rest is just putting the motor back in the bike the reverse of the breakdown. We will be doing a separate video on setting timing as well.

[@inglesconrichard]

So many thanks for these videos guys. I'm currently rebuilding an LML Star Engine, which suffered a bent con rod and your videos have been absolutely invaluable.

[@inglesconrichard]

My LML Star is a 150cc 2 stroke, which is identical to the Vespa PX 150cc. They also make 150cc and a 200cc geared 4 strokes plus some automatic scooters.

[@FreakMoPed8]

yep, the lml crank is crap. it can be perfectly twisted. its an excellent excercise object for crank centering :) the second one in my "good crank bad crank" Video is an lml. and also v2 and v3 is still not state of the art. hopefully u replaced it and used a proper one, mazzucchelli ie

[@inglesconrichard]

Hi Mista Yes I used a mazzucchelli, that was in August 2015 and I've done about 30,000 kms on it since without problems, or at least with out crank problems

[@FreakMoPed8]

good! no worries they wount appear as mazzuchelli is fine!

[@Topuesto]

Man, I miss the fat guy with the skulls bracelet. Has some very funny jokes and expressions and he created an awesome buddy-motor-series along with Robot.

[@donnysosa2479]

Great Videos guys! I’ve come back to 3 of these engine rebuilt videos countless of times to help with my 125cc engine rebuilt project. Absolutely invaluable resources for learning these little motors. From a marketing stand point, these videos definitely help your business as you’ve earned mine through ordering parts and some crankshaft work. These vids may have created more tech calls (certainly by me!), but you guys absolutely rock at your customer service and sharing your time and knowledge with us weekend warrior mechanics. I’ve been wrenching for years ... rarely do you find this level of service. Damn, sorry for riding you guys so hard this morning... probably cause I finally got my engine all zipped up ! 😂🤷🏽‍♂️🍻

[@ToxicCexCell]

These videos will get popular. More and more locals in my are getting motorcycles and mopeds. There's not alot of DIY on engine repairs for these bikes.

[@VespaMotorsport]

We'll try to grab some footage of it next time the bike comes by the shop! Thanks for watching!

[@ahmadazizbutt8682]

You guys are doing amazing job love from Lahore Pakistan

[@glennwilson81]

Just done my oil seal ...brilliant video showing disassembly and rebuild ..really helpful :-)

[@AbdulHakim-uq1nv]

Thank you for the video , so entertaining

[@dfusco73]

Great video , the camera man was excellent

[@kevinell6605]

Brilliant vids, easy to follow and informative.

[@rodolpheb1353]

i need a 1 week formation with this guy to do all those technical operation on my px 125 ! :D head rememebering all spare parts piaggio number ! PRO !

[@doc3793]

Robot and Steve, thanx for all the videos, I must have watched them hundreds of times. I am from Pakistan, and restoring a 1963 Vespa with a VBC motor. I suggest when you mention torque or other units in non metric system it gets confusing for non American audience. For example 11 foot- pound of torque don't sound good with 11 mm nut. Plz go with metric system as well for rest of the world views. My two cents. Regards Dr Rizwan Malik

[@embrj1453]

U guys do a fine job, if i ever own a Vespa i would take to you guys... good job..

[@MrDennisrosengren]

Great video!! Iam right now rebuilding my SS180 engine and was thinking how to heck get the crank on place again! thanks alot from sweden!!!

[@tarnait]

And as you can pull in the crankshaft with the clutch (!), you can pull in the drive shaft with the wheel drum, no need for special tools! And no need to hammer any shaft!

[@petercurrie9959]

yes. dont ever seat the drive shaft or any shaft with a hammer.

[@aleonovich]

Was looking forward to seeing it fire up! All in all great video except for all that background chatter towards the end. Really enjoyed watching the video and learning some techniques. Cheers!

[@FreakMoPed8]

vespa motorsport: no offense guys :o) but from a tuner point of view there are quite some tips that should be told as we want to give the best state of the art tips that actually help not so advanced hobby mechanics and avoid them unneeded learning lessons. SO some more tips from the tuner side (check my utube channel & the FMPguides for more tips) also for part 2: 00) in general: its a classic assembling of malossi tuning parts. thats ok, but there are better setups u can realize for your vespa scooter. as it still has the original crank with only 45° inlet timing this setup - even though italian named products are used - it will stay weak as this limits the intake. furthermore the malossi 166 is the weakest tuningkit available for 125/150 vespa and if u extend the transmission to 64/23 this wount really help… my guess is 11-12hp at the wheel 0) comeon! this rotary valve pad is visible completelly c*** up and has to be made new. as u need 0,05mm that the rv works 100% and u DONT have any blowby this is the most important thing to do with a rotary VALVE engine (as u check the valves at a reed VALVE engine)1) if you have marks on the crank like that.. see 1) 2) if cheeks of a cranks are easy twistable they are usually done, throw it away. a) but for original setups okish, b) for a tuned engine NOT appropiate. simply throw it away 3) revising a crank is not worth it, buy a new one or better a good used old ones 4) its a malossi 166 piston, sounds malossi and strong, but isnt, its the last recommendation for tuning as it is really weak in low rpm 5) the original 150 piston is dark cause it has blowby, cause it - the rings - simply wernt run in properly. especially iron cast kits have to be run IN 6) pls DONT use the big compressed air miller tool but a small dremel tool ie with sandpaper rolls 7) the malossi 64/23 is WAY TOO LONG for this setup as it is only standard tuning (no fine tuning with cyl and inlet timings adjusting) u cant reach a much higher topspeed if the engine is too weak to pull it... malossi 166 timings: 170/115/27,5 thats not bad BUT the crank only has the original 45° so the whole setups will stick to the low level tuning of a plug and play tuning 8) for the primary alsways use the 200 double springs 9) the original cheap pressing plate clutch basket needs to get a ring if u use stronger springs as it will open & blossom 10) u DONT need the silver malossi springs! they are way too hard for this basket and not needed this setup. i would just use new piaggio and add 2 more SIP L springs. malossi are 3 times harder than original piaggio springs, thats way to much! compare: a malossi sport 221 engine with 25hp at the wheel only needs 150% spring force, so why 300% here with this aprox 12hp engine? BEWARE: the harder the springs the faster u damage the big crank bearing as u press the clutch directly to the bearing cage (clutch spring measurements search google for "freakmoped cluthsprings" and u will find the table that compares different spring) 11) therefore always use a 9 ball bearing that has 1 rivet point more at the cage 12) no need to drain the clutchplates in oil, it works exactly the same when you oil them while assembling the clutch (thinnk of how dry they come out of the engine anyways) 13) put adhesive under the clutch bush 14) use adhesive for the cruciform too 15) dont cut any bolt of an vespa engine, use NEW ones esp when it comes to the carb and crankcase bolts 16) this is the wrong sealing for this case, if there no rill use the brown iron sheet, if ther IS a rill use the blue cortecco rubber as it expands in the rill (yes, thats why its there) 17) this cortecco has to be shortened 0,5mm in the height, otherwise its dangerous that it stripes the bearing 18) closing the case: the weak spot of all evspa engines is on the small halfe where the kickstarter sprocket is, the sealing surface unfortunately is ony 1,5-2,5mm there. so to avoid the engine sucking gearbox oil u need to put&fix the paper sealing on the small half. 19) DON use the bad castle nut, thats not state of the art, there are nut with a collar, lock washer fanwheel and adhesive 20) that push rod plate is visible done, always use a new pressure 21) 1:13:54 the big egine rubber should be replaced ;) as it is visible cracks 22) use sealing mass for the cylinder bottom 23) malossi 166 head has a rubber ring, for all other heads: always sandpaper them otherwise they are not tight = false air. cheers! & drive SAFE!

[@NPTtriumph]

Great video, thank you!

[@ChicagoGuerrillaJournalist]

Your the man!

[@VespaMotorsport]

You really want to make sure you don't get ANY metal shavings down in the case. Trying to do that with the motors still installed might be difficult.

[@user-sm8wo3dj5z]

do those clutch metal discs have a position on their notch or not really? thanks!

[@Vini-rm2ss]

excellente vidéo !!! bravo !!!.....

[@mikedemod]

Very Helpful. thanks.

[@peterwriede7772]

great video still, I see how you rounded the edges of the exhaust port, do you do the same for the transfer ports? (any hole with the cylinder rings travelling across them)

[@ToxicCexCell]

Great details! keep it up

[@tarnait]

What about checking the port timing, and checking the squish band? I was really shocked, that you didn't show that essential part.

[@vespamotorsport253]

Not necessary at all. This is a bolt on kit for street use, there is absolutely no need to check port timing and squish. There's also no additional base gaskets provided to even do so. These Malossi cylinders are pretty good out of the box, most are better off not touching a thing on them

[@SuperFrancesco1951]

Beau travail!!chapeau!

[@charleshollow5734]

Would there be a benefit to polishing (or at least smoothing out) the extremely rough cast in the exhaust port on the Malossi cylinder?

[@dulla_paree_tz2431]

Good

[@gerisyandrayusman241]

AWESOME!! THAAAANKS!!

[@kevinchamberlain7928]

Your robot is pretty life-like! Yes, I can tell it's a robot but at glance it could fool some.

[@HoniSoitQuiMalPense]

hey man, great, great videos. One thing though, when you talk about the clutch assembly and oversize shims and measuring for tolerance are you mixing measurements in inches 1/6000th with mms ? Becomes kinda confusing. Can you at least quote both? Otherwise, as said great vids!! A big thanks!!

[@EFlowe]

Whats the part number on the skull bracelet? ; ) Great video and timely. Currently rebuilding a P125.

[@Mark-wx1ho]

So you can carefully 'hammer out' a crank shaft but not hammer it in?

[@actarus74fleed]

Vespa valore e stile ITALIANO 🇮🇹🇮🇹🇮🇹

[@tristantrajan]

You got an editing error around 1:10:00

[@blackwhiteghost7898]

Like vespa

[@pauldavis2480]

i've just rebuilt mine, the engine is still out the scoot, and when in neutral and hub is spun i here a knocking noise,but only when engine is at a slight lean angle? when i hold up straight as it would be once in frame, the knocking stops when hub is spun? is this just because i have no oil in the engine yet? all gears seem to work fine. only problem is the knocking in neytral. any help please..thanks..great video. paul...

[@mclordhelmet]

Good videos! Part 3?

[@Ottomojo]

Same question was asked some comments ago, I watched some other videos and they never make adjustments on the crankshaft. Wouldn't the wider piston head hit the crankshaft opening pulling back in if you do not adjust this? Or doesn't it go further back in than shown in the video? (scared the wider head will hit the edge of the crankshaft when testfiring the engine. Thanks

[@kdharris1265]

My headgasket is different, it has 5 holes and part of the gasket almost completely covers up a port (inlet/outlet). I'm doing the Malossi 210 kit on a P200E. Mmmm, yeah. Is the grinding procedure similar?

[@mansdaz]

what about setting the engine up, timing ?

[@tarnait]

Big mistake NOT replacing the bearings. I always, always replace all seals, o-rings and bearings when i split the engine. They are cheap, and in case of failure they mess up the whole engine! Especially if you grind the transfer ports. But nevertheless i like your videos.

[@903colorado]

Hey guys thanks for the videos, ive got a vintage w/ a 166 kit does about 62mph, do you think id be happy w/ the malossi upgear kit? I do alot of touring long rides and dont want to be wide open all the time. Some say i wont be able to push that 4th gear? Any info is greatly appreciated!! Thanks again!

[@magicwands1]

fantastic videos Steve wish you were over here in england my friend at least we would now any jobs we had done would be done honestly and properly one question i have if you have time is what jetting should i use on the malossi 166 kit as my px 2008 disc scooter will start when cold but after a run when its hot it wont start up again subbed you my friend and keep those vids comming they are brill best wishes to you all ,,,,,pat

[@FreakMoPed8]

as u have a 2008 px your engine case is one of the less good ones, they all come with an oilsucker directly from the factory. this causes warm start Problems. so first: check and solve the oilsucker, 2) then u can set the carb right, now its definitels NOT stable. 3) ensure proper fuel supply! 4) carb Setting with touring exhaust and 5&8mm drills in the air filter and 75° race crank will be 160/BE3/mainjet 125 and idle 2,7 with a si24 carb (all of these engines are similiar) only pnp on the 45° original crank = mainjet 120 and idle 2,9. checkout my channel for detailed Infos :) cheers!

[@GIANNI-PALU-ET3IT]

la ghisa oramai è cosa vecchia e sorpassta, l'alluminio non lo conosciete?

[@artiyanyan3903]

scoteris from indonesia :) vespa extrime

[@dhamot_saab]

***** can u plz tell how to overcome this vespa sound, when engine running at idle makes noise during engaging and disengaging clutch :( Stella clutch noise? Vespa Clutch Rattle

[@nitindhiman8346]

Open your engine and go to lathe shop for engine bearings seats works

[@marcoscruvinel4731]

how do I get a cap from this wasp or a T-shirt, I'm from Brazil and I have a PX 200

[@federicopierfederici1490]

La guarnizione sotto cilindro?

[@imaww1]

mantabbbsss broo...

[@tazisa11]

Dear Vespa Motorsport, Thank you for the video : it's very helpful. I have a Vespa PX VNX2T and I will install a kit Malossi cylinder 166 cc. Is that the machining of the crankcase is required and mandatory or only suggested? If I do not machine/rework the crankcase: is this going to damage the engine? I do not necessarily want improved performance. Thank you Yours

[@FreakMoPed8]

its not mandatory, but it improves the Performance. most important Thing would be a race crankshaft...

[@matycee]

why don't that fancy cam of yours focus on the close ups??

[@jesusalayon8809]

seria bueno que lo tradujeran al español.

[@ray4945]

Wheres part 3????!

[@jtqthetieman]

Is there a part 3?

[@VespaMotorsport]

Jason Queen That's it! The rest of the steps are pretty much just the reverse operation of the tear down steps in PART 1. Let us know if you have any questions. Thanks for viewing!

[@jtqthetieman]

***** Well, darn. I was enjoying watching you work on this. Thanks for the great videos.

[@forevercomputing]

+Vespa Motorsport Should have been a P3. The whole "does it run" is the thing we all wait for... The most exciting part. I personally felt disappointed.

[@FreakMoPed8]

wanna see running tuned engines? checkout my channel ;o) my guess for this project: the Rotary valve pad is visible damaged (as the crank cheeks were twisted, the crank should be replaced too) so therefore this engine will have BLOWBACK Problems cause the rv doesnt work 100% this causes Setting Problems with the si carb cause u go leaner in low rpm and therefore its too lean in high rpm. in general the malossi 166 kit is the last recommendation for rv Tuning and the Transmission is way too long for only 45° original crank inlet timings see more tips in my above Standing comment. cheers!

[@rajatsingh8348]

Hlo sir can you just tell me how to open the frame only without opening the engine parts can we remove full frame just make that

[@215alessio]

who is better malossi cylinder and piston kit or polini kit? I was forced to buy the polini kit because there was no malossi available for my px 125 anno 2011

[@215alessio]

did some research and the alluminio Polini kit was better on the low rpm band as many informed me. while the malossi is great on the high rpm band

[@GIANNI-PALU-ET3IT]

Alessio S polini to fast -,malossi to power and long time function- sorry for my english

[@FreakMoPed8]

malossi 166 is actually pretty weak in general and esp in low rpm. there is a reason why no one uses it ;o) u are perfectly fine with the polini 177. BUT be aware of your oilsucker engine case (as it is younger than 2001) that causes si carb Setting Problems. as well the crank of the 2011 Version is not the best, its an China crank they even dont put the pia Emblem on the conrod anymore... the vespa quality gets worse and worse...and the Price raises of course.

[@215alessio]

you hit the nail on the head, yes the vespa 2011 is not italian, they only do the final assembly in italy, i quess the parts are oriental and are final assembled in italy paintjob and the bolt on wheels But I doubt it's china, I think they'r made in india wich is even worst! ps parlo anche l'italiano ;) le nuove vespa fanno schifo e sono fatte in india percio evitate il marchio piaggio in generale

[@215alessio]

si il malossi si dice di essere piu' durevole!

[@user-zr8tb3gh2e]

أزاى أطلع صامولة وقعت ف الكاربيرتيرداخ الشفط

[@henrikrasmussen9480]

ciao FOREVER

[@e.meukens2575]

Has he a spare of 2 eyes at home? No eyeglasses on when he working with the airtool?!

[@ahmedragabmorsyahmed7217]

I own one of these and I want to modify, such as those with you how much money you need to modify the engine but I need a very strong and I want to install exhaust turbo I hope you reply And also been modified exoskeleton and became a much better and will send you a picture of her But I needed to communicate with you to talk about amendments and again I'm waiting for your reply on me I hope that I will not be overlooked in the newborn Thank you

[@amedeobarra4222]

metti le fasce come uno scassacarrozze

[@elizabethlee1756]

9:46 hm... that strikes me as weird.

[@koolkar55]

Bad background talking at 105:00

[@anggahariyo6606]

can you gif one sparepak to my i like vespa recing plis

[@dbraben]

Great video but FFS ...safety glasses!

[@Doitall1983]

everything looks right nut not Malossi please!!!!!!!!!!!!!!!!!!!

[@Folsomdsf2]

please never ever ever use that tool to shape that ever again :-/

[@wolverhamptonbiker2132]

cool video.check out my motovlogs sometime

[@josedavidrestrepomolina4272]

traducción a español

[@koolkar55]

Noisy background talking is very annoying.

[@josedavidrestrepomolina4272]

translate to Spanish