Modern Vespa

I've got coolant leaking from somewhere. See pic. It appears to go away when I'm riding, and then return once the scoot stops and cools. Any thoughts on where it could be coming from and possible repairs to stop it? I've checked all the hose areas and they appear dry. The thermostat location is dry. The water pump housing and weep hole are dry. Thoughts?

I had a leak like that on my 2009 GTS 250 when I first got it with 20,000 miles on it. I read that it was the head gasket. I replace the head and base gasket and the problem went away. I wasn't a big leak when I found it.

Agreed. Run it hot lately? Pull the pet carrier to see if the leak is from a hose.

Thanks. I ran it hot a few weeks ago and also a few days ago, and didn't see a clear leak from a hose.

1. Any thoughts on continuing to ride with the leak? Is that a horrible idea?

2. Please PM me if you know of a good Vespa mechanic in Connecticut or central Mass.

I would expect that if the leak is very slow AND you check the level frequently then no harm.

I had a slow leak on my supertech that started 1 year after purchase. by drying it with paper towels and then leaving it for a day then repeating a few times I was able to trace it to the hose clamp at the thermostat. tightened it and all good.

i lover paper towels

So, I have no leads on someone to fix this… Can I just drive with this coolant leak forever and top off the coolant occasionally? Or will it get worse and thus necessitate repair now/soon?

There aren't that many places for coolant to leak. I know it's annoying (I had a similar leak on my GT200 at one point), but it's much easier to find the leak now in your garage than on the side of the road 25 miles from home!

When I was chasing a leak someone (I think Motovista) gave a very helpful tip that led me to the problem: dry everything thoroughly and spray all around with foot powder. This makes an even, white film that can make it easier to see the coolant leak source.

I hope you figure it out (the easy way)!!

if it's just the clamp, then replace it. no special tools or skills needed.

if it's the gasket, then eventually it'll blow out. damage to the engine is most likely to occur. and these things seem to happen at the most inconvenient time.

get it repaired if it's the gasket.

Good advice. Wanna visit Connecticut and do the repair? You like beer, right? Treehouse Brewing has world-class beer and it's like 35 minutes away…

I wouldn't be opposed to it!

just not at this time of year!! ha!

but in all seriousness, do you have any scooter or motorcycle contacts nearby or who's the closest? might make a weekend out of a drop off and a repair and a return.

or... what's your skill set and tool/work situation like?

it's all surmountable, just might have to get a little creative.

Lol. Thanks for being open to it… Connecticut is awesome and lovely, but the weather often sucks. It was over 60 degrees today, but tonight it will be in the 20s, and then Friday we are getting over 6 inches of snow. This Sunday, I was ice fishing on 10 inches of ice in 50+ degree temperatures. It's crazy.

I have all the tools to do it, but god awful skills and little time. There are some local shops, but I've had bad experiences. I may call around and gauge their experience and comfort level with the repair. Lots of places claim they can "do" whatever, but then I get my scoot back missing screws from the engine air filter housing (true), or misdiagnosed (true), or whatever. Vespa is a niche brand here, and not too many are familiar with Vespa scoots. The best luck I've had with a repair was with the "MCU/Throttle Body King of the World" who exports MCUs all over the place and happens to live in New Britain, CT… He replaced my throttle body in excellent fashion for a good price, but he was just being nice. He's an engineer or something who side hustles by hacking/repairing MCUs and then shipping them around the world via eBay. Good dude, but he's busy with his job/family/side hustle.

Idk…If anyone out there has an idea on a qualified mechanic in my area (or even Boston or New York), please PM me. Thanks again, Greasy and MV Forum members. Best forum ever!

Isn't there a Vespa dealer in New Haven, CT? I think it is called New Haven Powersports but it was a few years back when I looking at buying a scooter from them.

Did you see if Robot has any video's on replacing a head gasket? That may help.

And another near Hartford, and another near Danbury? Seems like more choices than most of us have.

On the other hand, if it IS just a loose clamp?

Unfortunately, Robot doesn't work at every Vespa dealer. I've had Vespa dealers use non-OAT coolant, fail correct diagnoses (which they could have caught by swapping in parts in stock and checking), and miss replacing screws. There is also one dealer who wouldn't work on my Vespa beyond basic maintenance because none of their techs were trained. Not that there are thousands of people from Connecticut reading this forum in the dead of winter, but perhaps it is telling that I put out a call to PM me with leads on a good Vespa mechanic and I've received zero PMs. Lol.

Probably had zero response on your call for a good Vespa mechanic in the area as there may be none. This is probably, based solely on my readings of this forum, is that the majority of people here do their own work.

That said I believe that Seacoast Sport Cycle in Derry NH has a Vespa trained mechanic. I had bought our first Vespa's from them and they had to go in at 600 miles for the required valve adjustment. I took them back to them for that so there would be no warranty issues.

You may want to call them.

So, I think I have traced the coolant leak to the circled part in the pic. I don't know much about engines, but is there a gasket in that location from which the coolant could be leaking?

That's your head gasket - and a prime suspect.

Thanks, Jim. Any thoughts on checking/torquing these (cylinder head bolts, maybe?) to the proper 11 to 13 Nm (if they are indeed the cylinder head bolts)? Perhaps that could potentially compress the gasket just enough to stop the leak… Is that possible? Could it hurt?

The gaskets are metal with a coating on them. If the coating deteriorates and flakes off in the area around coolant passages it will start to leak. This happened to the base gasket on my BV 350.

The job isn't as bad as one might think, and due to the easy removal of the pet carrier and lack of plastic panels on the Vespa I suspect it is much easier to repair than it was on the BV350.

Thanks for your confidence in me, but there's no way I'm going to attempt this repair. I read that professional mechanics can take 5+ hours to do this job right. That's 50 hours for me. I'm 10 times as slow as a professional!

A few questions for the GTS engine experts out there:

1. Are there other maintenance items that can be replaced while the engine is apart? Does the water pump come out with this fix? If so, should it be replaced since the previous owner didn't change the coolant for over three years and that may have corroded the seals. Are there other gaskets or things that might be replaced?

2. Any performance enhancements that might be easy to do (or easier to do) while making the repair.

3. PM me if you have a good Vespa mechanic in the CT, MA, RI, or NY area who might want to tackle this job.

Thanks again.

Update from March 8, 2022:

I'm going to have the local scooter shop fix it. They have lots of experience with scooters, but not necessarily Vespas. I think they are experienced enough to replace the gasket(s). It's far beyond my comfort level. Let me know if anyone has any suggestions for upgrades (or other replaceable items) while they are working on it. Thanks again!

How many miles on the scoot since last maintenance? It may to worthwhile to check the valve clearances.

head has to come off to do the gasket, so the valves will have to get checked on reassembly.

PM Sent. Two very solid Vespa mechanics in the NY area.

Update March 11, 2022

The scooter shop (also a Vespa dealer) that said they could do the gaskets never called me back after I emailed them the VIN. I finally got impatient enough to call them yesterday. They reconsidered and now cannot do the gasket because they don't have trained technicians.

So, yesterday, I called the next closest Vespa dealer. They can likely do it, but it could take 2+ months!

I have a few other leads on mechanics thanks to Motovista.

Thanks again

They can't have a technician of any calibre if they've no-one to do a straightforward head gasket swap. Good luck in finding someone to do it.

Updated March 12:

So, I was about to ride the scooter down to the other Vespa dealer (it's about an hour away), but I called them just to confirm the 2+ months timeline. I spoke to the same service manager, who decided that now they are so busy through riding season that they can't get to it until AFTER riding season… lol… That's like November in these parts.

How difficult is this repair? I've done a lot of maintenance (variator components/belts, wheels, brakes/fluid, oil, coolant) and replaced a few items (starter, ECU, fuel injector)… I've checked the valve clearances, too. But I'm thinking these engine gaskets are out of my league. I've heard it's a 4-5+ hour job for a pro…Is that the case?

Last year I picked up a project WRX Sti with a blown engine. I pick my fights so I had a local reputable tech rebuild the engine for me. Youtube certified mechanics make all look easy but I pick my fights. It's all about comfort level...

See my other post: 2017 GTS300 - cooland leak?

New to me 17' GTS had a small leak and I concluded that it was outside temp related. Kinda like "cold hose" leak on old diesel engines.

I did look around the web, called couple local shops and figured out that if not in a rush I can do this...but there is a 50/50 chance it will end up at a shop when I'm done since I know my luck lol

All I can say is: pick your fights...hope this helps.

If you're doing these things, the head gasket is in your wheelhouse. Time consuming, sure. But three weeks from now you'll be out on a ride with a prideful grin on your face and a deeper understanding of your beautiful machine. Follow along with Robot and take lots of pictures along the way. You got this.

I agree - it's not that difficult or mind-bending. It just takes time. No special tools required - but a torque wrench is essential if you think that's 'special'.

When I did mine I replaced the base gasket as well just for piece of mind. I used Robots video and it was a piece of cake.

nah, that's declining the work with out actually saying: no, or we're not comfortable do it, or we don't care to do it. which, at that point why would you even want somebody like the to touch your bike?

it's easily a 5+hr job, but there's not any real magic to it. just lots of tedious work. if you can do all of that, you can easily tackle this job.

literally here are the hardest parts of this job for a home mechanic:
>space to work in and have the body stuff & parts strewn about
>getting the body up high enough to pull the motor
>figuring out where and how to position the motorless body while you do the work
>dedicated area for the engine and bits while you work on it.
>cleaning it all off super-duper clean before tearing down and installing gasket
>figuring out how to maneuver the bike and get the engine back in
>fighting off the allure of the beer fridge

really, that's it.

break it down into manageable chunks. pull the motor one evening. clean and disassemble the next. clean and inspect the following. install gasket and button up the top end the next. check your work and throw everything back together for install the next. toss the motor in the following. fill and test and check the next. test ride and double check your work and you're done.

you could easily break that up into 2hr chunks.

so it comes down to: space, time a little bit of tools and fearlessness to tackle. and you're gonna need some beer. and maybe a friend to help manhandle the motor/body removal and install.

you got this!

Greasy, thanks for breaking it down and for all your help. You've clearly identified the most difficult part!

I'm a school teacher, and we have a week long spring break in a couple of weeks, so I'm going to do a step each day. I have everything to do the job (except the gaskets and a super accurate torque wrench).

In an ideal world, I'd let students help me out with this during the school day. Some of them are very mechanically inclined and would love to do a project like this. But, we fill their days with solving for c-squared, learning about the Articles of Confederation, and book clubs. All great things, for sure, but it makes school less-than-fun for some kids who would prefer more hands on learning.

I have a knack for that...

order up all your parts well ahead of time, some shipping has been taking longer than usual with some suppliers being 1000% on the ball and some others letting it fall by the wayside. so, get all your supplies and bits squared away before hand and that way you'll have a smooth journey.

you can easily knock this out over a few days, and like Jim said, the only "exotic" tool you'd need would be a torque wrench. go slow, take your time and you'll be fine and dandy.

in jr high and high-school my shop teachers and the ones that taught social studies, economics and science were always the ones that could figure out how to make the subject matter be relatable and engaging. not that I didn't have an appreciation for English and math, it's just that my brain doesn't work that way. y'all have a thankless job and we are all better for it. I try and give back with my little bits of knowledge, wisdom and technical knowhow. but full time teachers are the real MVP's

Thanks to Greasy and the other awesome forum members, my wife and I got the engine out! A few questions:

1. Do I have to replace the base gasket? I think it is fine and just the head gasket is leaking.

2. Do I need to re-ziptie all the electrical zip ties I cut?

3. What should I use to replace all the "one time use" clips I snapped? Worm gears? Other one-time use clamps? Is there a brand someone recommends?

Thanks again!

2. yes

3. worm gears are fine. make sure you get ones that don't have holes as they are apparently more likely to damage the hose? not really sure how much it matters but play safe. and get stainless steel

I think the GTS uses the same studs to hold the cylinder and the head? In other words, by removing the head you must also disturb the base gasket. Personally, I'd just spend the $10 and get a new one for the rebuild.

As was mentioned - you are releasing the torque on the base gasket. It should be replaced. You should be able to (gently) turn the crankshaft until the wrist pin just becomes exposed, remove the clip and wrist pin, and remove the cylinder and piston together. Done correctly you don't need a ring compressor because you never remove the piston from the cylinder. It is literally nothing more than a few extra minutes of work.

you and the missus are amazing!

1- nah. in fact I wouldn't touch it.

2- sorta kinda maybe. I do mostly but not all of them. use discretion

3- 100% geared hose clamps (dealers choice here)

on the hose clamps there's opinions of shielded and non-shielded. personally, I've never had a problem with run of the mill worm gear auto parts store clamps. just get something decent that's not total dog shit and you'll be fine.

*pours a cup of coffee*
*opens the max pack of cookies*

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