Modern Vespa

I'm hoping someone else has this combo and knows the best setup?

I fitted the kit yesterday and here's my setup so far:

2012 PX125 (cat model).
DR180 Kit.
TSR Revolver Exhaust.
Standard 20/20 carb, changed main jet to 112 (after trying higher ones).
Air filter heart mod.
NGK BR7HS plug.

I've done 60kl on it today (assorted short town trips) and the plug colour is perfect chocolate brown.

Something is not quite right, it's very 'sputtery' in mid to low revs (at around 30mph in 4th gear) open the throttle and it responds fine.

It's not too bad if I'm honest but I'm left with doubts on the setup, in the DR kit instructions they 'strongly' reccommend using a standard exhaust?

I have a Sito Plus twin pipe brand new I was going to put on another of my PX's but I wonder if it would be better suited on the DR180?

Any advice on this?
Thanks in advance.
Simon

Do you mean it's four-stroking? Does it do this only in 4th, or low revs in all gears?

It's similar in all gears but mostly notice it in 4th, it's that low to mid range cruising revs, open the throttle slightly for more speed and problems gone but back off to cruise and it sputters again.

Hope I made sense? but to put it simpler it won't ride smoothly at 30 - 35mph.

I have a DR177 kit on my Sprint, I also have a Sito Plus, running a 24-24 carb with a 160 idle jet and the main stack is 160 air bleed, BE3 diffuser and a 118 Main Jet, once I got it right I haven't had to touch anything in 4000kms. Hope that helps.

Thanks Badrever, I may go to a bigger carb in the future.

I have made progress, took the TSR Revolver off and put the Sito Sport (twin pipe) exhaust on and it runs like a dream, far more pull and smooth.

Still using the 112 main jet though I may increase it as it's running very slightly lean.

Doesn't look or sound as good as the TSR Revolver but a far better exhaust for this setup.

Update for anyone else looking for a similar setup:

I changed the main jet to a 115, I finished running it in and I'm very happy with the setup, amazing difference in all ranges of the engine, the flat spots have all but gone and pulls similar to a P200 now.

One of the hills I used to struggle on would end up going slower and slower on and just about get up it at 30mph now flew up at 50mph

Fastest so far was 65mph on a windy day.

Off to Tenby scooter rally at the weekend on it 150 mile trip so will know more after that but so far so good.

know a bloke called keith? we called him sherlock


shrewsbury lad,,,,,,,,,,,,,,,moved back there


josh.

Yeah got himself a Lambretta over here now.

This guy?

Hi there. I fell upon this post and have a few questions:

I have a similar set up. 20mm carb 112 main jet and sito plus exhaust. This is all on a px125e.

The bike to me feels like it has zero guts.

You mentioned yours now pulls like a p2. How so? What is your set up? Did you install the 24mm carb?

I’m racking my brains trying to dial this bike in.

Any other suggestions or steps for optimal performance? Send them my way.

Thanks everyone.

I've only just got my dr177 right after getting expert advice on here. I've got dr177 24mm card and sip road 2. I'm on ac140 be5 mixer and 120 main. I've got slight splutter on tiny throttle in third and fourth gear but about to change to a slightly leaner pilot jet to iron that out. I'm talking 20mph with slight throttle for the splutter. In what I'm gathering from the info I gained on here is maybe the mixer might need changing. You will likely as I have done experiment and it takes some time. I'm sure. So since I was recommended to put the be5 in from be4 it seems a lot happier and less splutter. Mine drives like my old p2 as well accept its a bit more revvy with road 2 and reaches similar speeds. Remember that 65 mph indicated is more likely about 60 with GPS. They are about 6mph out on higher indicated speeds. Mine indicates 110 khm which is 68mph but GPS is 62.5 mph I'm sure the gurus on here will chip in soon with what to do as thx to them mine is driving really well with chocolate plug. I'm hoping to get the p2 tractor pulling with the polinbox pipe. I had it on before but not setup right and the pull in lower gears is amazing; that exhaust does make you feel its like a p2.. You can feel the front wheel lift. I've learned a lot about jetting this week all thanks to the guys on here and when you get it perfect its a personal achievement. Quite frankly 60mph is fast enough for me so if you are getting this all day with the dr kit thats good..

I would have to agree.
carb jetting really is a subjective science. But once you get it, leave it.

Is your carb box matched to the 24mm carb? I was told unless you do that, the 24mm carb is kinda useless.

If I could do 40-50mph I would be very happy with this set up. 60mph is gravy!

Let me know.
Thanks for your response.

Yes the carb box is bored out to match the inlet diameter. I've learned this week that jetting can't be rushed and make sure you have plenty of time to drive the scooter and plug chop and adjust. The other thing I've learned is buy a jet kit with all the sizes in a range as far cheaper than buying one or two. I've got all the help from the guys on here and it's saved me money and importantly given me peace of mind as I've done it right and know how I got there. Seizing can be a frightening and dangerous experience, came off a p2 when younger at 50mph and all because the carb was lean. Didn't get back on scooters for 13 years after that.