AMF ss250 and Mikunis

Wolf Wizard /

So I have an old Arimachi AMF Harley ss250. I got it as a roller with everything stripped off of it and in a box. over the last two years I've been buying parts and slowly reconstructing it. De-rusted the tank, and por 15'd, new petcock, New NOS wiring harness, new battery, and I'm ordering a new CDI unit soon. My main concern is the carb was one of the few things not in the box. I've looked all over for a stock one but they are always in "unknown" (probably busted) condition on ebay for like 100 bucks which to me is sketchy. The stock carb is a 32 PHB(E) AD. But I mean in the spirit of mopeds apparently if you throw a mikuni at a two stroke it will run with minor tuning. so I was wondering which mikuni carbs are meant for two strokes i know there are different kinds with different atomizers and such, but I've always done dellorto carbs on my mopeds, so looking for carb suggestions.

any info greatly appreciated thanks guys!

Re: AMF ss250 and Mikunis

I'm not a big fan of mikuni, not the easiest carb to dial in. Gotta have all the jets, needles, atomizers ect. to make it work properly. I would get a dellorto vhst or vhsb, they are really nice carbs and are designed for 125-300cc two strokes.

Re: AMF ss250 and Mikunis

i've put mikunis on everything from four stroke honda road bikes, big 2t dirtbikes, you name it. I've never changed a needle, slide or atomizer on any of them. Just pilot and main and they always run good.

I had one of those big dellortos (factory carb) on a 600 KTM four stroke and it was a total piece of shit. really hard starting, in fact i sold it because it was so annoying to start it that i didn't want to take it places, the guy i sold it to replaced it with a TMX pumper and it turned into a one kick bike just like that.

when i'm putting weird different carbs on different bikes i usually start by finding a similar bike that uses a readily available carb. So that means like 2 stroke, air cooled, same age range, reed valve, etc. Then either use an OEM carb from that bike, if its easy to find, or a repop of an OE carb, or look at what people with that bike are upgrading to and get one of them. When i put PE20's on my CB175 race bike they literally ran with the jets that came in them right out of the box. I think i ended up going down like two sizes and never changed the needle or pilot.

Soooo for your SS250, i think thats a reed valve air cooled 2 stroke? I would look at a DT250 yamaha- i happen to have one- it uses a Mikuni VM that is like 30ish mm. The factory carb isn't marked since its OEM.

You could probably run either a PE, PWK or VM 28, 30, or 32 with nearly out of the box jetting. I like the VM's just because i have tons of jets for them and they always run pretty ok for me. The OKO PE clone carbs are also pretty good and real cheap. The PWK's aren't much more and flatslide so in theory a lil' bit more performancey but probably wont matter.

TL;DR i'd buy one of those 32 mm china pwk clones and make it work.

Re: AMF ss250 and Mikunis

Wolf Wizard /

i have a huge stock pile of dellorto needles and mains for the phbg series. you both gave some really good pointers there and ill have to do a little research checking into each, though the idea of a new carb does sound nice to me than a used carb from a different bike. thanks guys!

Re: AMF ss250 and Mikunis

Ktm600 is a real dick to start no matter what if its not tuned right. Probably just needed a larger choke jet. Pwk is an ok choice, but I would say don't get the China one. The polini pwk series that they sell on treats are super nice and the parts are cheap. You can call me a purist, but I dont like the idea of a Japanese clone carb on a street tuned Italian race bike.

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