Modern Vespa

Thanks Gickspeed
I will contact Ralph Bollag and see what he charges..

Would you even have to split the cases or could you fill in in place?

If you end up using a filler, I would fill in the same as welding shows in the picture.

If I filed it I could fill as it is…without splitting the cases…I think it could also be welded….

Seriously, BGM need to step up and make some dedicated cases to suit this cylinder and then 90% of the works done, then you can just focus on timing squish and jetting.

They also need to make either a sport version or race,short stroke/long, rather than a Jack of all trades that doesn't really excel in one particular area. That way your not chasing your tail trying to dial it in.

That old repair is thin!
At least there's a nice pocket to tooth into there, if filler is the only practical option.

Small wire brush, maybe a 1/4 can of brake cleaner, then this:
https://www.scooter-center.com/en/modelling-metal-weicon-repair-stick-titanium-115g-we1003

I have some JB-weld on the way…
The surface is rough so if i clean well with aceton and brake cleaner it should stick.
I got a quotation for the cost of welding the hole shut but it means The engine needs to be split and rebuilt which im trying to avoid as it has only done 1000 miles since the last rebuild that I paid a so called "professional" to do…

In this forum Ive heard only good things about JB-weld even though welding is the best solution…

Some notes on my similar project, and a question:

Went on a break-in ride yesterday. Recommended 1hr nothing over 5k hilly cruise around. A LOT of midrange power.

New cylinder bolts. Long end towards the cases. New bolts came with thread lock you want in the cases. Added a little more blue loctite and waited a day. With the middle size (.5mm?) spacer ended up with 1.1mm squish.

CHT sensor arrives today. Going to get a better idea of how it compares to the VMC.

Unfortunately I don't have an un-drilled filter. Going to block the holes and see how it goes. Eventually I'll ditch the filter and jet accordingly. Curious to see how the recommended PNP setup compares, though. Using jets from the supplied kit (below) and a 130mj.

Speaking of recommended setup, I'm still surprised that they recommend a stock filter. The SC jetting page is auto-translated. They say the un-drilled filter isn't a "throttle." I looked up that word in German. A Drossel is a skinny bird with a narrow beak?
So not a restriction.
Seems like that setup is a drossel. The filter will also richen the mixture when dirty. One could also jet with a dirty filter then clean it.

https://www.scooter-center.com/en/carburettor-tuning-kit-nozzle-set-bgm-pro-for-vespa-px125/150-with-bgm-pro-177-cylinder-kit-main-jet-set-secondary-jet-mixing-tube-air-correction-jet-bgm1770nej

Some good points @Ray8
I live in Switzerland and speak german and some of the translations via Google are not always correct or easy to understand
the word should be Drosseln not drossel which when translated means "choking".
I was also surprised they recommend the standard filter without the extra holes, but i guess they want a starting point or recommendation that they know works, be it safe.

But your right I think also that the motor should breath better with the heart drilled out.

A question about the temperature sensor in the head.
I guess this is compulsary as I dont see a blanking bolt to close the hole where the temp sensor should be?
How did you route the wires for the temp sensor through the plastic head cylinder cover? Did you need to drill a hole or did you reroute it some other way?

Cheers

Last edited by Robbie 11 on Thu Feb 03, 2022 11:23 am; edited 1 time in total

Ignore my above comment....after thinking through the JB weld idea Ive decided its a bloody stupid idea.
Why bother spending the money to fit a nice kit when underneath the kit is a bodge that may let loose at any moment?
It may not, but there is peace of mind with knowing that its been done properly when Im riding thats more important than saving a few dollars.
I only found this repair by accident as i wanted to exchange the Pinasco kit for the BgM. But in the end Im happy i found this bodge underneath as now Im sending it to be professionally repaired.

thanks to everyone for the great tips and advice...

Robbie the hole is blind, so doesn't need to blanked off.

You are a very smart and wise man. Anything worth doing is worth doing right.

do it nice, or do it twice.

never time to do it right the first time, always time to do it right the second.

Cases seem to weld up nicely and tolerate a lot of heat. They are not delicate flowers. I do have a low mileage engine though that had a scored rotary pad skimmed with JB weld. This doesn't worry me enough to pull it apart at this point.

Bloody Hell, Im an idiot...
Too used to working on my Yamaha RD 350 LC(water-cooled)

How did you route the temp sender cable from the cylinder cooling cover?
Under the cover or drill a hole?

Thanks Ginch...

Last edited by Robbie 11 on Thu Feb 03, 2022 11:54 pm; edited 1 time in total

I'll say this... you only hear good things about JB from the people who have good things to say about JB weld.

I drilled a 1/2" hole in the center of the cover and ran the connector through there. It has about 6" of heat insulation, so one could probably just route it through the spark plug hole.
That's the easy part. The more difficult task is routing a connector wire to a gauge where you can read it.

Regarding your repair, I suggest you do a search/pose a question to a forum where Weicon Titanium is more frequently used:
https://www.germanscooterforum.de/

You could also email Scooter Center with pictures. Takes a few days to get a reply.

Another commonly used German repair epoxy is Uhu Endfest. Judging by the color of your repair, that's likely what was used. Your repair isn't a crack, nor under pressure. Number one failure there would be an improperly prepared surface.

Forgot to mention keying the surface.


Dremel

Then the sensor I will try and run it through the spark-plug hole.
Not sure if I should go for a simple Malossi Temp guauge or fit a SIP speedo with the temp guage built in…

Ive decided to get the hole in the casing welded.
I just want peace of mind.
I want to make some tours of the alps in Switzerland 🇨🇭 in summer, so better safe than sorry.
Im still waiting for the feedback if they are able to weld it closed without splitting the cases. But if they need to split the cases, then so be it.

I almost went the JB Weld path but then had a feeling that I would regret it.
I studied everything about JB Weld or other German products in the German forums and the experience is pretty much the same as here. Some swear by it and say its the best thing since sliced bread and others say its the last thing they would use.
I guess everyone has to make there own decision.
On the end Ive already spent a small fortune on this Vespa. I might as well spend a few dollars more and enjoy it.
Thanks for the pic, interesting way of preparing the surface…

Cheers

Carb Set-UP

So the recommended carb settings for a pretty much plug & play BGM177 with a 24 carb and Polini box are as follows:
55/160 idle jet
BE3 mixer
160 air corrector
130 Main jet.

I would like to start off richer in all areas to prevent a seize and have a good safe start point.

So I thought of the following:
50/140 idle jet
BE3 Mixer (BE2 would be too rich i think)
140 air corrector
135 Main Jet

Any thoughts and recommendations would be welcome

Thanks

I think you'll find the 135 Main Jet is too rich with the 140 AC. Start with the 130 and see if it rev's out cleanly at WOT in 2nd gear. If so, then go up a jet. If it stumbles, then go down a jet.

I would not be surprised if you wind up with a richer idle and atomizer, too.

Thanks Chandlermann.
I will try and see how this feels as a starting point…

Would suggest starting with AC140 BE5 and 55/160. 135MJ should get good heavy WOT splutter. This is a necessary step to prove you have decent fuel delivery. Jet down once proved.

Thanks Jack.
A question from a jetting virgin….
BE5 surprises me?
Your explanation for using a BE5 would really interest me? Its two jumps from the BE3.
I will do it and I trust what your saying 100%, I just dont understand it.
Your feedback will with no doubt save me a seize 👍

BE3 is weaker and certainly too weak for a BGM 177. This does however, depend on the air filter for the final jetting. A vortex and bellows to the frame gives the best results. Starting rich does no damage. Being a jetting virgin, it could be blown up before noticing it's not ok.

Thanks Jack…
Im only running a standard filter without the holes drilled….
Cheers Robbie

In case you don't already know, atomizers aren't straight-line 1 to 6, lean to rich. Each was designed for a specific build, and numbered in that way.

With your un-drilled filter, the recommended jetting is the safe setup. Manufacturers want safe.

I only have drilled filters around, so I'm using a 48/140 (same a/f ratio as the 55/160) and a 130/BE3/140ac stack for now. It's rich. Still a work in progress.

Thanks Ray….
Really appreciated…

Hi Jack,
What initial jetting would you suggest if he decides to go vortex and bellows only?
I have the same setup. Just pretending to ask on his behalf here.

Was thinking a 50/120 and 130/BE4/120ac, similar to the VMC Stelvio/Polini setup I had success with. Is this close?

Hi Robbie,
You mentioned earlier that you were considering the SIP speedo. Not sure if you are aware, but that speedo can be connected to a lambda sensor, in addition to the CHT and fuel gauge.

Provides you with a lot more info as to the health/performance of your bike, and less knocking on wood and Hail Mary's before a tour.

The wiring and setup is a bit tricky, but might be worth looking into.

Thanks Ray
Sounds like a good option.
I was thinking of the Malossi or Koso guauge mounted on the glove box due to the simplicity… and cost… but this could be another option…

Cheers
Robbie

I have a Koso CHT and generally like it, especially its large display, but it's really pretty garbage engineering. I wouldn't recommend buying one as a result.

It has 12v DC in for powering the backlight, but then requires a CR2032 battery to power the CHT itself. The backlight input is extremely sensitive to voltage spikes. Mine burnt out almost immediately when I had a wire rub and send un-regulated AC into the DC side of the harness.

It chewed through batteries constantly, like every 2-3 days, so I eventually replaced the battery with a 12v->3v transformer so I could run it off the bike's electrical system.

Also, it has no static RAM for holding the units (C or F) of the gauge, so for a Fahrenheit person like myself, every time it loses power, I have to manually flip it back over to F.

They may have corrected those design flaws in a subsequent version, but if they haven't, I'd avoid it.

Thanks chandlermann...
then i will stay a way from that KOSO guage

Came across this and thought of your project.
Uses Uhu Endfest.

That's a good video. I would be more inclined to use epoxy if I wasn't planning to do long distance trips or just used a scooter for low mileage around town kind of trips. The more I read about tuning stuff, the more I think a close-to-stock plodder is the best thing for me.

I've landed on close to stock plodders as my solution as well.

Don't get me wrong, I love all the tuning stuff and am always reading up on it. I even feel like I understand the basics of what is being done. I'm not ruling it out for future builds.

But not having been on a bike for 30 years and finding that a stock VBB gives me plenty of ya-ya's buzzing up and down my little street, I'm good with starting with the basics.

nothing wrong with a little extra, I'm just not going chasing the dragon these days...

a solid cylinder kit with stock carb and an improved box pipe is my jam these days.

good god. for $25.00-$35.00 someone will TIG weld up those case. For earlier cases involving machining the gasket surface, probably looking at $65.00-75.00.

little price to pay to have it done right.

not in LA at that price!

even a simple next over is damn near $100 these days

you don't have to go hog wild. a simple gasket match takes very little time and very little material out. then just dial in specifics (squish, mainly) and you're set to go. throw slightly larger carb at it if you want and snap on a box exhaust and you've got a nice little tug boat.