keuk

Step by step then.

New 62mm piston received, back to the 128° for intake About the timings. Do you have this machining mark in the transfert port ? If I use the line of the red arrow, I have 120/150 with a 0,5mm gasket. As the machining mark is not that deep I wonder if the 120 are really accurate. As Alex suggest, I will increase the exhaust height to reach 160° to increase the blowdown, do I enlarge the flange to 62% instead of 50% too?

I got it ! Thanks that is clear. By the way, my guy has updated the corebox and the pattern and should be ready to launch new models of the manifold on saturday .

What is the recommended squich on the 160GT ? What is the 0,8mm Rüstand Alex was talking about ?

Or the full kit: https://www.vespacenter.es/tienda/carburacion/carburadores-componentes/kit-carburacion-125-150-160-goma-directa-con-filtro-phbg19ds-detalle

Yes they sale parts like that on the spanish websites: I made printed parts too to fit on the original manifold. But we are still struggling with the overhangs on the printing process resulting in bad surfaces

Or https://www.leboncoin.fr/vi/1607207019.htm

This guy has probably the part: https://www.milanuncios.com/motos-clasicas/ducati-dellorto-207314789.htm Or this guy: https://www.milanuncios.com/motos-clasicas/dellorto-ub-ua-ma-me-263328703.htm By my side I think I will test another new piston, I have 142 inlet and 0,5 gasket and already at 120 for transfert port. I would like to figure put how it works first with near original diagrams before I try to improve something

It's a pity to modify the original casings, furthermore you will have to change or modify the crankshaft. What about a M1X ?

About the reed valve I had this in mind too, but I didn't go further than a PLA prototype.

I thought I would have lowered them a little bit increasing the barrel diameter to 62. What is Rückstand ?

Do you guys also have this timings on the original barrel ?

I’m back on the original setup, 19er, to see first how the 170cc and the Sip road work. The sip road has a volume close to a px125 I guess. I have increased a little bit the inlet timing by increasing the piston squirt cut from 126 to 140 according to Bollag’s advices. And timings are 120/150. And I have grinded a little bit the original manifold to make it match perfectly with the cylinder and the yellow spacer. On the original setup I had a 84 main jet. I tried 92 100 110, but in each case the full throttle is weird, bowwww and it’s a pain to reach the maximun rev of the engine. Like if it was too lean. The rest of the power band is great . I would like to solve this before struggling to find the good atomiser/needle matching on the Vhst. Could it be the inlet timing or the exaust port too low ? Maybe the ignition ?

Sure. I have noted one for you .

Arround 60€.

Alright, a batch of 5 parts will be on production soon.

Great I have asked him for a small series !

I can ask for a small batch.

Manifold proto to mount the VHST 24, till now it was easy, now I have to find the correct setup... what a pain in the ass.

That is the same one , mine sandcasted by a youtube video maker and caster. the new model for VHST PHBL PWK is coming this week.

Bakelit ?

Wir könnten das so machen, aber ich fürchte, der Vergaser berührt den Zylinderkopf.

The aluminium 24er sandcasted manifold is in production right now at least one prototype.