Modern Vespa

Hi all.

Currently have a 2004 px125 with SIP road 2 exhaust.

So decided I would like a little more power. Not after a high rev screamer. Reliability is a must. I use the bike daily and at weekends.

I'm looking for very much a bolt on kit. Probably keep my autolube and 20/20 carb ( if that's possible) Nice and simple. Like I said just after a bit more torque rather than high top end speed. I currently have the electric start still attached. I'm open to taking that off as I only use it every now and then. I know some kits need some work to get them to pass the flywheel.
Just wandering from people's experiences what maybe a good fit. Read that the bgm177 is for electric start and the dr177 is a basic kit if not a bit dated. Any help greatly appreciated.

Thanks for great info. I think I am leaning towards the bgm kit. Seems to meet my needs well. Any idea what kind of main jet would be needed? Currently on a 102 with the sip box exhaust. Runs quite rich on short town trips with some 4 stroking but prefer that to lean. Out on country roads runs really well.

The DR 177 is ancient, like technology from the 80's. you will have to remove material from the side of the cylinder for the electric start ring to fit. There is NO reason to use this cylinder. NONE.

Youre right, they are old technology, called an Olympia back in the days, however, they do go on and on and extremely reliable More of a capacity update then a performance kit. Ive run mine for 7 years with a SIP road 2.0 and 24mm carb and it pulls genuine 65mph GPS all day, and every day.

Thanks for all the comments. I think for what I am after in terms of a simple bolt straight on kit that will just give me a bit more power up the hills etc a DR177 kit is well suited. With its added reliability also. I will keep the 20/20 carb for now . Any ideas on what main jet to start with ? I have a 140ac and be5 and 102 mj already in because of the sip road 2 .

buy what you may, it's certainly your call-

i will add-

Both the BGM and DR are "bolt on kits."
Both the BGM and DR are "reliable" *when set up correctly (timing, jetting, etc)

price wise- BGM $376.00, DR $254 (Scooter Center).

The additional $122.00 is nothing compared to the modern equipment the BGM supplies.

The BGM comes with full setup instructions including the jetting you have asked for several times.

*The DR177 is something i might use if i was in the middle of nowhere and that was the only thing available to get me to a destination.

Thanks for all the comments. I think for what I am after in terms of a simple bolt straight on kit that will just give me a bit more power up the hills etc a DR177 kit is well suited. With its added reliability also. I will keep the 20/20 carb for now . Any ideas on what main jet to start with ? I have a 140ac and be5 and 102 mj already in because of the sip road 2 .

If you must have a simple cheap iron bolt on kit buy this one
https://ve-uk.com/product/vmc-super-g-177cc-cast-iron-cylinder-kit-vespa-px125-150/

As said the DR kit, although it can run reliably, absolutely any other 177 kit does whatever the DR 177 does but better.

I skipped/missed the first portion of this discussion, though I would also have told you to get the BGM if I'd chimed in.

But, since you went the DR route, I happen to have a Stella (LML) motor with a DR on it along with a stock crank, 20/20si carb, and a SIP Road 2. Other than being reed versus rotary, it's pretty much as like-for-like as you're going to get.

I just went and checked and the jets are : 55-160 idle, 160-BE3-112 main.

That may be a bit rich, but I bought the motor, intending to install it to sell the bike, and then didn't because reasons.

Anyways...that's probably as close a match to your build as you're going to get, because most of us around here are of the "Friends don't let friends run DR's" school of thought.

Finally, a few thoughts as you get into your project:
1) Be sure to lap the head before you assemble. For those prices, you don't et quality, and DR heads are notoriously uneven, thus prone to head leaks even with a head gasket.
2) My jetting above should be your starting point to dial it in, not a "known good" setup, especially if you're going to run it hard. Get a set of main jets and maybe BE1 or BE5 atomizers and see what works best for you.
3) Pressure test. Spend the very few bucks to build a pressure test rig (search here for examples) and make sure the motor is air tight. Especially if you're going to run it hard. Nothing kills these motors faster than WOT+air leaks, even on a bike that seems good under around town conditions.

Good luck.

Thanks very much for your suggestions. A great starting point. Yeah seen a few videos about the cyclinder head. Will run it rich while it runs in anyway 👍

I have built a lot of DR180 engines over the years (the old cast iron cylinder with the massive squish). Prob more than any other spec because its super cheap and easy. SIP R2, standard crank and carb. Its not so popular now (prob been 10 years since I last did one) but I had a look at my old book for jetting starting points that i have used. Feedback has always been ok (most people seem to have been happy enough to run forever with the starting settings it would seem).

SI20/20 - 45/140, 140-BE5-106
SI24/24 - 55/160, 140-BE3-115

If that's any use to you

That's perfect. Thanks for the info 👍

I never had the DR or the VMC or the SIP. I like Malossi though.

A 20.20 is plenty of carb for a 177. I'm still using one with autolube on my cast iron Malossi and seeing max revs in the high 9000s and top speeds of 72—73 mph on the flats. No, that is not plug-and-play, but it shows you what a 20.20 can do. As for your jetting, back when I WAS mostly plug-and-play, an AC140 would have required a main jet around 108-109. You could also pair that MJ116 with an AC160 and be pretty close. Probably would be a little rich, but with a DR kit you might not even notice.

Thanks for that. I managed to get out just 13km town riding. Kept below 40mph. keeping the Revs low . It's very rich . Pretty much 4 stroking most of the time. Would clear up with a little throttle or a small incline. Do you think I should drop the main jet a few sizes? I'm just mindful of keeping it on the rich side while I'm running it in for a while .

Yes. Based on my experience, I would be comfortable going straight to an MJ110 but, if you are doing this for the first time, you'll probably feel better if you walk it down just 1 or 2 points at a time.

Well dr kit fitted. Took a bit to get it started. But went in the end. Lots of compression when kicking it over . Waiting for a break in the rain here in the uk for its first tentative test run. Stick with the autolube 20/20 carb for now. 55/160 idle . 140ac be5 116 mj. Probably stupidly rich but will see how it goes while I'm running it in .

Yes. Based on my experience, I would be comfortable going straight to an MJ110 but, if you are doing this for the first time, you'll probably feel better if you walk it down just 1 or 2 points at a time.

So 112 mj fitted. A little better in the four stroking department. Still there most of the time. Would a little adjustment of the mixture screw help? Think I set it at 2 3/4 turns out to keep it on the rich side. Probably a bit too far maybe ?

The mixture screw only affects the idle circuit, which should be ok with the 55/160. I would leave it at 2.5 turns out and keep walking down the main jet.

Thanks. I think I'll jump to the 110 mj and keep the 160/55 idle at 2.5 turns out. That should still be rich enough for running in period shouldn't it ?

Should be. Presumably you are not running at sustained WOT yet. You won't be able to finalize the MJ until then anyway. In the meantime, just jet it so its rideable.