msk_motori

Ok, thank you for your help!

Question for the experts... What exhaust can you run on these MV frames with a p125 motor, so that the main stand doesn't hit the exhaust? Polini box hits the stand :( and I dislike the MRP relocation kit. Original PX - clears SIP road 3.0 - ??? Expasion chambers - ??? What about taffspeed mk4 left hand exhaust? I can have one for a reasonable price... Thanks for your replies ;)

It is because I know a few german words and I want more people to understand the drawings. Sorry, if it is a problem, I will only write in english. Still thanks for all your help. So option 1 it is! I will prepare for the milling and bring some results in the upcoming week.

Ok, then how about this? I thought of a plan on how to save the cylinder. I measured the aluminium base gasket and it should have been 8mm but it is 8.3mm. I can correct this and the piston ring still wouldn't be able to pop out of the cylinder. Then I can use a small port-cutter to raise the ports about 1mm. If I do it correctly and good, the angle of the port shouldn't really change. I know the timing would be excessive but I think it could work better then it is now working. Which of these options would be best? If you have other ideas, I really welcome them.

Yes it does work! Find a M10 bolt and a soft bread and then stuff it inside, hammer it, stuff it,… repeat until the bearing pops out.

Now I have it all dissasembled, sadly found a small issue. What do you think? Nicasil isn’t cracked, only aluminium is on it. 600 sandpaper to scuff it up and same on the piston and run it? The tolerance between cylinder and piston doesn’t seem like it changed. Also, first time I have used the bread technique. I didn’t think it would work 😂

Squish was 1.3mm for 54 stroke. I think that is too much. On 51 stroke the manual says 0.9mm. How much squish should I aim for? I think 1mm is adequite. On the side of jetting, I have tried many combination - k57 k24 and also a lot of different emulsion tubes. I cannot remember all of the combination, but I think I should start to take notes 😅

Hello! After 3 years of being on this forum and just watching from the sidelines, I want to create a small build project of my own. More precisely, really fine-tune my dream project. I´m from Czech republic and as far as I know, I am the only idiot :D in our country, who wants to have a crazy smallframe. I have a German market PK XL with Quattrini M1L-56 which has broke down due to bearing failure on the secondary gearbox shaft. But before that happened I drove it for a few kilometres and the engine did not feel right. Before it gets to "power" or "ressonance in the exhaust" there seems to be a dip in the powerband and I don´t know why. Hope you can help me and sorry I´m writting in english, my german is not that great. This is my setup Quattrini M1L-R 56 (cylinder timing below) BGM 54/105 full circle crankshaft Vhsb 34 Egig Taipan exhaust Malossi 10-15-18-20 SIP reinforced clutch basket with 26/69 Bolla Elaborazioni XL2 clutch SIP vape sport at 24°

Hello, if possible, I would need a bit of help with my jetting... Setup: Stelvio alu (p&p) Pia original 57 stroke crank LTH membran for Si carburetors Original Ducati with 19° static Sip V2 fuel tap with tough fuel hose (against kinks) Si 24 (ND 62/160, HD 135/BE3/160, Slide 04) fuel chamber bore - 2.7mm When standing, from full throttle to idle, the revs fall down normally without any issue. When the scooter is under load, if I release the throttle above 6000 rpm, the revs fall a bit slow and when I try to blip the throttle, it feels like it doesn´t have any fuel... The spark plug looks lean-ish. Logical thing to do would be to go HD138, but this is rich and with ND 62/160 I can´t go richer since the scooter then start "four-stroking". I tested against leaks, checked the flatness of the carburetor, but I did not find anything... If you have any advice, I will take it. I´ve been stuck with this problem for 5 months. I don´t speak much German, so I´m sorry for writing in English.

Questions for the experts, who are running Super G cylinder for a while now... What do you think about this setup? Can it be reliable in the long run? Last year I had run it with SI 20 and original air filter (48/160; BE3 - 160; HD 118) and got around 103 km/h vmax and felt like I "could" lift the front wheel up. This year I got SI 24 and I really don´t know what to expect... maybe 115 km/h vmax and more mid-range torque that good for touring? Also what do you think of this start for jetting? (55/160 or 62/160; BE3 - 160; HD 135) Setup for season 2022 Super G with CNC gold head + 1,5 mm base plate (119°/178°) = 1,5 - 1,6 mm squish (if measured correctly 10,7:1) 57/105 PIA crankshaft (25 mm cut out on closing side) LTH reed valve for SI carbs SI 24 with MRP venturi 23/65 PIA primary with Polini rep kit VNX1T PIA gearbox banded 200 clutch (7 spring with Polini clutch kit) Polini box complete PIA P200E ingition (i think more than 2kg) And lastly, I have a Kytronik unit laying around... Would it really be a benefit to run it? Thanks for help!

Hello, sorry for writting in english... Yesterday I got hands on a stage6 vhst 28. I would like to try it on classic polini setup (Polini 133GG, membran polini 24mm, 2.56 with original 4th, Proma exhaust). I am thinking about the setup: min s38 max 104 slide 50 choke 60 AQ 266 or AQ264 needle ??? Which neeedle based on your experince would you try? i.e. - I already have D22, D25 and D34. Thanks for any help or advise! ;)

So progress after a week... My dad basically created a manifold for me, mainly because I don´t know how to use welder, but I want to learn it in the summer... It was created using 5mm plate for the inlet base on the cylinder, 2mm plate for the transition from the round hole to square hole and from 90° pipe used around radiators and stuff (internal diameter 27mm). It may be improved over time, but for now, it works. After that I test-fitted it, painted it black with high temperature paint and mounted it, ready for first start... Initial setup of the carburetor was a bit different from what I wrote last time... My carb came with different parts, so first setup was: 50 slide D34 needle second frop top 270K atomiser 122 main jet 53 idle jet 60 starter After many failed attempts, it seemed like it was wayyy too rich and basically it ran very poorly just for 4 seconds. It also kicked back real hard when I wanted to start it... So after a day, that I wasted with this, I sat down and found dellorto´s manual for setting carburetors. So I came up with a second setup with pieces from phbl 24 which I have on my Polini 130. I also cleaned and redone my ignition with 0.35-0.40 gap and set it up and 23-24° BTDC 40 slide D22 needle 2nd clip from top 270K atomiser 122 main jet 50 idle jet 60 starter Funny enough, my dad was that day with me and just for fun said... "lemme see how it runs" It was a cold start so I switched the choke on and right on the FIRST kick it fired right up! I was sooo happy, because I did not thought that I would get it running by myself with no help from others. So after fine tuning, just on the stand (It´s cold outside and I don´t have a throttle cable long enough to fit it.) I finalized my starting base setup... 40 slide D22 needle 1st clip from top 270K atomiser 122 main jet 50 idle jet 60 starter idle screw 3,5-4 turns out mixture screw 1,5 turns out The engine runs real nice, starts nice, I think the response is great and it doesn´t kick back... If you want you can hear it on video. So now, I need to order some parts, like slide, jets and needle and I need to sort out my air filter situation, because there is not much space... Quattrini M1XL has that much space also for an air filter, so I will take inspiration from there.

So my friend has found this cyl head, I thought I could use it since mine is bit damaged. I thought I will modify it in a same way you did... Out of curiosity, from what 150 might this cyl head be? Could be VBB or Sprint? Yes, I chamfered all edges a bit so the rings would not catch. I did not measured the rings radialy, but just by looking, they seems to have a good thickness all around. But I measured the piston ring gap and they are just a bit worn out, but since the cylinder has still good compression, I decided to leave them. I don´t think they will cause me problems, but if I will be restoring the MV in the future, I will definitely have the cylinder rebored/redone.

But the plan kind of changed to o-tuning project (on budget), thanks to... @Pholgix MV 150/S2 topic @andreasnagy MV 150S 1964 topic. I already read those topics and decided to redo my cylinder. First of all, there´s some pictures after dissasembly (Spark plug is new, so don´t look at color) So after seeing the measurements, I had the timing of... Transfer 120° Exhaust 147° Blowdown 13,5° Exhaust width 60,5% Inlet 127° (symetrical 63,5° in TDC and BDC) So after consideration I redone the cylinder without base gasket to Transfer 120° Exhaust 154° Blowdown 17° Exhaust width 60,5% Inlet 133° (symetrical 66,5° in TDC and BDC) I also did not touch the piston, exept cleaning it on the top. Rest of the setup: - Original MV 150 exhaust for now, but in the future I would like to get a SIP Road 2.0 for MV or Polini box for PX, but I would have to modify the exhaust inlet. - Dellorto PHBL 26 facing towards back (still need to create manifold and sort the air filter position) - Original gearbox, primary and clutch - Head ??? - Ignition ??? Now... I also have some questions... Should I use the Bajaj 12V ignition? On ebay, I found one for 47eur... I would like to use different head, since mine has the spark plug thread a bit destroyed... What would be a good compresion ratio? I was thinking about (10:1 - 11:1) - I don´t really want to source a Bajaj head... - my friend might have a PX 150 (d.58) head, that I believe might have better compression than original MV - or should I search DR135 (d.60) cyl head or with that size diameter, it would not work? With what carburetor setting would you start? With what atomizer, needle, slide? - I thought about modifing the basic setting of carburator 60 slide D36 needle 270K atomiser 122 main jet 30 idle jet - into changing just the idle jet (just for basic start and maybe a small ride, if everythings works out good) 60 slide D36 needle 270K atomiser 122 main jet 50 idle jet

*My mother tongue is Czech, but I can speak English. I will write in English, but feel free to respond in any language you want. I hope it´s OK * Hello! This is my first topic in the "oldie" section and I hope I did not messed up something by creating a new topic for MV Sprint. Here I would like to show and conversate about MV Sprint with 04C engine number from 1966 and on it´s o-tuning and my future restoration. About my MV... I bought it in 2018 at Mannheim from Spanish friend for what I think was a good price. It was rough and scrached a lot! The engine did no ran (at the spot), but it had clean registration and was in sort of presentable shape. After coming home next day, I cleaned carburetor and put gas into external tank (mine was cloged) and it ran good. Because the rear wheel seal was leaking and I did not know anything about this engine, me with my dad (because back then I basically did not know anything about two strokes and engines) decided to rebuild the engine. I quickly found about the differences of the construction from Italian models and succesfully sources what I needed. After rebuild I got it registered, but could not ride since I did not have a A2 drivers licence... After some time I got my licence and I had about two weeks to befriend and learn on my Sprint, because VWD2019 was happening! After that my dad helped me set my carb correctly and from that point - summer 2019 until late summer of 2020 - I did NOT touched the scooter at all! (apart from reupholstering the seat) And I was daily riding without problems for about 5500km (which I think is amazing for 55 year old scooter with an old 6V system!) then it started having a lot of issues. It was starting very rich, carb was leaking (even after resealing and checking everything) and the mixture screw was tight at it could be. Then it also started leaking gearbox oil and the front suspension was like a pogo stick, which did not brake at all! So basically after no servicing (because I was dumb ) for more than year, I decided this spring to modernise the scooter (on a budget) and do proper maintanance since I gained some knowledge after 2 years. The plan: 1. Replace tires (Crappy low budget Mitas for more quality Heidenau tires) - used Heidenau KR80sr 3.50-10 2. Replace front suspension - replaced only the front damper 3. Change brakes - Replated only front pads, back was breaking good. 4. Stop the oil leak - Replaced leaking o-ring at clutch cover 5. Change the carburetor for more modern type, because I gave up on the UA19S1 - I could not set it properly - want to use a Dellorto PHBL 26BS, because I got it some time ago and it is only sitting on a shelf 6. Replace 6V ignition for 12V - want to use a Bajaj 12V ignition for small cone cranks. Are they reliable, what is your opinion on them?