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Mikuni vm20 and vm22
Posted: Fri May 16, 2025 11:10 pm
by jk50
How are these for a buddy 50 with a BBK? The bolt spacing is a bit wider than factory. Wonder if it could be adapted to the factory manifold? I notice the buddy 125 comes with a 23mm carb.
Re: Mikuni vm20 and vm22
Posted: Sat May 17, 2025 4:05 am
by jk50
I mean, I know it could be adapted but, I am no welder or fabricator.
Re: Mikuni vm20 and vm22
Posted: Sat May 17, 2025 12:41 pm
by sc00ter
Dellorto 17.5 or 19mm. Easy to tune and parts are common. I prefer the 17.5's myself.
Re: Mikuni vm20 and vm22
Posted: Sun May 18, 2025 3:41 am
by az_slynch
I have a VM22 on a shelf that I need to find to compare. The thing to know is that the Buddy 50 intake has the same flange pattern as the late 2T Honda scoots like the Elite SR and Dio, as well as the Kymco ZX and other vertical 2T Honda clones. The Buddy intake is nominally 24mm in diameter, so it can support a much bigger carb than stock.
That said, sc00ter's suggestion of a DellOrto 17.5 is a good option if it is offered with a comparable mounting flange. Some variants will support the existing cold start enricher (bystarter) and have a suitable port to connect the autolube pump to. You really don't need a bigger carb unless you plan to spin the engine over 11K RPM, at which point you should be considering an aftermarket race crank too. Jasil and Stage6 offer cranks if this is a consideration.
I used an Arreche 821 on my
Angry Buddy project and it was a great fit. Shame that it seems Tallares Arreche decided to stop licensing Amal's monobloc carbs at the end of 2023; they seem to be focused on EFI systems now.
Important note about Mikuni (and Arreche) carbs: they use main jets that are sized by volume rather than by bore diameter, like DellOrto or Keihin. There are charts online to help in translating the jet sizes between types to help better determine what you're looking for.
Please share some details on what sort of kit and pipe you're planning to use so we can help you select some suitable supporting bits. In the interim, I'll look for that VM22 and get pics.
Re: Mikuni vm20 and vm22
Posted: Sun May 18, 2025 3:54 am
by jk50
from Mikuni's documentation a 70cc 2 stroke would best be served with a carb between 18 and 22mm. to use with the factory manifold I imaging some welding and cutting will be needed. the Bolt spacing is wider, as well as the fasteners being larger. I was settling on the vm20. I currently its a Malossi iron 70cc kit and a sport pipe.
Re: Mikuni vm20 and vm22
Posted: Sun May 18, 2025 1:32 pm
by sc00ter
I've never did a BBK on a Buddy 50 (or a RH50) but I recall Prima or NCY sells a replacement intake to accept round mounted carbs. Oh, and before I forget, if this Mikuni is a flat side get ready to learn dirty words when tuning. I hate flat side carbs. I just want to set-it and forget-it, not play endless fine tuning games.
Also: I've always bypassed the electric choke on all my builds and swapped over to a flick lever for choking, usually mounted above the transmission case. It (flick lever) just makes everything easier when starting the scooter cold when or in cold conditions.
Re: Mikuni vm20 and vm22
Posted: Tue May 20, 2025 2:18 pm
by sc00ter
I talked to the guy who has the mean Vino 2-stroke. He's trying to find time and motivation to pull his Vino out of the non-climate controlled shed and see what is needed to get it running. I think he's kinda over 2-stroke tuning as well BUT I did tell him if he gets the Vino running it might motivate me to grab a RH50 before Genuine quits importing them and replaces them with a boring 4-stroke. I've already been on Scootertuningca and have a general idea on what I'd purchase.
What exhaust are you using on the Buddy 50?
The Malossi street cast is a good bbk. It works great with a Yasuni Z (restriction removed) or the Yasuni R.
Re: Mikuni vm20 and vm22
Posted: Tue May 20, 2025 3:15 pm
by jk50
Scooterworks sport exhaust at the moment. I should put a vacuum guage on it and see how much vacuum it has at WOT.
Re: Mikuni vm20 and vm22
Posted: Wed May 21, 2025 4:02 pm
by jk50
Re: Mikuni vm20 and vm22
Posted: Wed May 21, 2025 6:26 pm
by sc00ter
NICE find! That makes life much easier than swapping out intakes. It also let's you choose what choke set-up you wanna run!